|  | Home | Documentation | README.md Source File updated Sat Aug 22 2020 by Robert van Engelen |

- Main Page
- Classes
- Files

- File List
- File Members

README.md
Go to the documentation of this file.
1
2 C and C++ XML Data Bindings {#mainpage}
3 ===========================
4
5 [TOC]
6
7 Introduction {#intro}
8 ============
9
10 This article presents a detailed overview of the gSOAP XML data bindings for C
11 and C++. The XML data bindings for C and C++ are extensively used with gSOAP
12 Web services to serialize C and C++ data in XML as part of the SOAP/XML Web
13 services payloads. Also REST XML with gSOAP relies on XML serialization of C
14 and C++ data via XML data bindings.
15
16 The major advantage of XML data bindings is that your application data is
17 always **type safe** in C and C++ by binding XML schema types to C/C++ types.
18 So integers in XML are bound to C integers, strings in XML are bound to C or
19 C++ strings, complex types in XML are bound to C structs or C++ classes, and so
20 on. The structured data you create and accept will fit the data model and is
21 **static type safe**. In other words, by leveraging strong typing in C/C++,
22 your XML data meets **XML schema validation requirements** and satisfies **XML
23 interoperability requirements**.
24
25 In fact, gSOAP data bindings are more powerful than simply representing C/C++
26 data in XML. The gSOAP tools implement true and tested **structure-preserving
27 serialization** of C/C++ data in XML, including the serialization of cyclic
28 graph structures with id-ref XML attributes. The gSOAP tools also generate
29 routines for deep copying and deep deletion of C/C++ data structures to
30 simplify memory management. In addition, C/C++ structures are deserialized
31 into managed memory, managed by the gSOAP `soap` context.
32
33 At the end of this article two examples are given to illustrate the application
34 of XML data bindings. The first simple example <i>`address.cpp`</i> shows how to use
35 wsdl2h to bind an XML schema to C++. The C++ application reads and writes an
36 XML file into and from a C++ "address book" data structure as a simple example.
37 The C++ data structure is an STL vector of address objects. The second example
38 <i>`graph.cpp`</i> shows how C++ data can be accurately serialized as a tree, digraph,
39 and cyclic graph in XML. The digraph and cyclic graph serialization rules
40 implement SOAP 1.1/1.2 multi-ref encoding with id-ref attributes to link
41 elements through IDREF XML references, creating a an XML graph with pointers to
42 XML nodes that preserves the structural integrity of the serialized C++ data.
43
44 These examples demonstrate XML data bindings only for relatively simple data
45 structures and types. The gSOAP tools support more than just these type of
46 structures to serialize in XML. There are practically no limits to the
47 serialization of C and C++ data types in XML.
48
49 Also the support for XML schema (XSD) components is unlimited. The wsdl2h tool
50 maps schemas to C and C++ using built-in intuitive mapping rules, while
51 allowing the mappings to be customized using a <i>`typemap.dat`</i> file with mapping
52 instructions for wsdl2h.
53
54 The information in this article is applicable to gSOAP 2.8.26 and greater that
55 support C++11 features. However, C++11 is not required. The material and the
56 examples in this article use plain C and C++, until the point where we
57 introduce C++11 smart pointers and scoped enumerations. While most of the
58 examples in this article are given in C++, the concepts also apply to C with
59 the exception of containers, smart pointers, classes and their methods. None
60 of these exceptions limit the use of the gSOAP tools for C in any way.
61
62 The data binding concepts described in this article were first envisioned in
63 1999 by Prof. Robert van Engelen at the Florida State University. An
64 implementation was created in 2000, named "stub/skeleton compiler". The first
65 articles on its successor version "gSOAP" appeared in 2002. The principle of
66 mapping XSD components to C/C++ types and vice versa is now widely adopted in
67 systems and programming languages, including Java web services and by C# WCF.
68
69 We continue to be committed to our goal to empower C/C++ developers with
70 powerful autocoding tools for XML. Our commitment started in the very early
71 days of SOAP by actively participating in
72 [SOAP interoperability testing](http://www.whitemesa.com/interop.htm),
73 participating in the development and testing of the
74 [W3C XML Schema Patterns for Databinding Interoperability](http://www.w3.org/2002/ws/databinding),
75 and continues by contributing to the development of
76 [OASIS open standards](https://www.oasis-open.org) in partnership with leading
77 IT companies in the world.
78
79 🔝 [Back to table of contents](#)
80
81 Notational Conventions {#conventions}
82 ======================
83
84 The typographical conventions used by this document are:
85
86 * `Courier` denotes C and C++ source code.
87
88 * <i>`Courier`</i> denotes XML content, JSON content, file and path names, and URIs.
89
90 * <b>`Courier`</b> denotes HTTP content, text file content, and shell commands with command line options and arguments.
91
92 The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD",
93 "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to
94 be interpreted as described in RFC-2119.
95
96 🔝 [Back to table of contents](#)
97
98 Mapping WSDL and XML schemas to C/C++ {#tocpp}
99 =====================================
100
101 To convert WSDL and XML schemas (XSD files) to code, we use the wsdl2h command
102 on the command line (or command prompt), after opening a terminal. The wsdl2h
103 command generates the data binding interface code that is saved to a special
104 Web services and data bindings interface header file with extension <i>`.h`</i>
105 that contains the WSDL service declarations and the data binding interface
106 declarations in a familiar C/C++ format:
107
108 wsdl2h [options] -o file.h ... XSD and WSDL files ...
109
110 This command converts WSDL and XSD files to C++ (or pure C with
111 <b>`wsdl2h -c`</b>) and saves the data binding interface to a interface header
112 file <i>`file.h`</i> that uses familiar C/C++ syntax extended with `//gsoap`
113 [directives](#directives) and annotations. Notational conventions are used in
114 the data binding interface to declare serializable C/C++ types and functions
115 for Web service operations.
116
117 The WSDL 1.1/2.0, SOAP 1.1/1.2, and XSD 1.0/1.1 standards are supported by the
118 gSOAP tools. In addition, the most popular WS specifications are also
119 supported, including WS-Addressing, WS-ReliableMessaging, WS-Discovery,
120 WS-Security, WS-Policy, WS-SecurityPolicy, and WS-SecureConversation.
121
122 This article focusses mainly on XML data bindings. XML data bindings for C/C++
123 bind XML schema types to C/C++ types. So integers in XML are bound to C
124 integers, strings in XML are bound to C or C++ strings, complex types in XML
125 are bound to C structs or C++ classes, and so on.
126
127 A data binding is dual, meaning supporting a two way direction for development.
128 Either you start with WSDLs and/or XML schemas that are mapped to equivalent
129 C/C++ types, or you start with C/C++ types that are mapped to XSD types.
130 Either way, the end result is that you can serialize C/C++ types in XML such
131 that your XML is an instance of XML schema(s) and is validated against these
132 schema(s).
133
134 This covers all of the following standard XSD components with their optional
135 attributes and properties:
136
137 XSD component | attributes and properties
138 -------------- | -------------------------
139 schema | targetNamespace, version, elementFormDefault, attributeFormDefault, defaultAttributes
140 attribute | name, ref, type, use, default, fixed, form, targetNamespace, wsdl:arrayType
141 element | name, ref, type, default, fixed, form, nillable, abstract, substitutionGroup, minOccurs, maxOccurs, targetNamespace
142 simpleType | name
143 complexType | name, abstract, mixed, defaultAttributesApply
144 all | *n/a*
145 choice | minOccurs, maxOccurs
146 sequence | minOccurs, maxOccurs
147 group | name, ref, minOccurs, maxOccurs
148 attributeGroup | name, ref
149 any | minOccurs, maxOccurs
150 anyAttribute | *n/a*
151
152 And also the following standard XSD directives are covered:
153
154 directive | description
155 ---------- | -----------
156 import | Imports a schema into the importing schema for referencing
157 include | Include schema component definitions into a schema
158 override | Override by replacing schema component definitions
159 redefine | Extend or restrict schema component definitions
160 annotation | Annotates a component
161
162 The XSD facets and their mappings to C/C++ are:
163
164 XSD facet | maps to
165 -------------- | -------
166 enumeration | `enum`
167 simpleContent | class/struct wrapper with `__item` member
168 complexContent | class/struct
169 list | `enum*` bitmask (`enum*` enumerates a bitmask up to 64 bits)
170 extension | class/struct inheritance/extension
171 restriction | `typedef` and class/struct inheritance/redeclaration
172 length | `typedef` with restricted content length annotation
173 minLength | `typedef` with restricted content length annotation
174 maxLength | `typedef` with restricted content length annotation
175 minInclusive | `typedef` with numerical value range restriction annotation
176 maxInclusive | `typedef` with numerical value range restriction annotation
177 minExclusive | `typedef` with numerical value range restriction annotation
178 maxExclusive | `typedef` with numerical value range restriction annotation
179 precision | `typedef` with pattern annotation (pattern used for output, but input is not validated)
180 scale | `typedef` with pattern annotation (pattern used for output, but input is not validated)
181 totalDigits | `typedef` with pattern annotation (pattern used for output, but input is not validated)
182 fractionDigits | `typedef` with pattern annotation (pattern used for output, but input is not validated)
183 pattern | `typedef` with pattern annotation (define `soap::fsvalidate` callback to validate patterns)
184 union | string with union of value
185
186 All primitive XSD types are supported, including but not limited to the
187 following XSD types:
188
189 XSD type | maps to
190 ---------------- | -------
191 any/anyType | `_XML` string with literal XML content (or enable DOM with wsdl2h option `-d`)
192 anyURI | string (i.e. `char*`, `wchar_t*`, `std::string`, `std::wstring`)
193 string | string (i.e. `char*`, `wchar_t*`, `std::string`, `std::wstring`)
194 boolean | `bool` (C++) or `enum xsd__boolean` (C)
195 byte | `char` (i.e. `int8_t`)
196 short | `short` (i.e. `int16_t`)
197 int | `int` (i.e. `int32_t`)
198 long | `LONG64` (i.e. `long long` and `int64_t`)
199 unsignedByte | `unsigned char` (i.e. `uint8_t`)
200 unsignedShort | `unsigned short` (i.e. `uint16_t`)
201 unsignedInt | `unsigned int` (i.e. `uint32_t`)
202 unsignedLong | `ULONG64` (i.e. `unsigned long long` and `uint64_t`)
203 float | `float`
204 double | `double`
205 integer | string or `#import "custom/int128.h"` to use 128 bit `xsd__integer`
206 decimal | string or `#import "custom/long_double.h"` to use `long double`
207 precisionDecimal | string
208 duration | string or `#import "custom/duration.h"` to use 64 bit `xsd__duration`
209 dateTime | `time_t` or `#import "custom/struct_tm.h"` to use `struct tm` for `xsd__dateTime`
210 time | string or `#import "custom/long_time.h"` to use 64 bit `xsd__time`
211 date | string or `#import "custom/struct_tm_date.h"` to use `struct tm` for `xsd__date`
212 hexBinary | special class/struct `xsd__hexBinary`
213 base64Binary | special class/struct `xsd__base64Binary`
214 QName | `_QName` string (URI normalization rules are applied)
215
216 All other primitive XSD types not listed above are mapped to strings, by
217 wsdl2h generating a `typedef` to string for these types. For example,
218 <i>`xsd:token`</i> is bound to a C++ or C string:
219
220 ~~~{.cpp}
221 typedef std::string xsd__token; // C++
222 typedef char *xsd__token; // C (wsdl2h option -c)
223 ~~~
224
225 This associates a compatible value space to the type with the appropriate XSD
226 type name used by the soapcpp2-generated serializers.
227
228 It is possible to remap types by adding the appropriate mapping rules to
229 <i>`typemap.dat`</i> as we will explain in more detail in the next section.
230
231 Imported custom serializers are intended to extend the C/C++ type bindings when
232 the default binding to string is not satisfactory to your taste and if the
233 target platform supports these C/C++ types. To add custom serializers to
234 <i>`typemap.dat`</i> for wsdl2h, see [adding custom serializers](#custom) below.
235
236 🔝 [Back to table of contents](#)
237
238 Using typemap.dat to customize data bindings {#typemap}
239 ============================================
240
241 Use a <i>`typemap.dat`</i> file to redefine namespace prefixes and to customize type
242 bindings for the the generated header files produced by the wsdl2h tool. The
243 <i>`typemap.dat`</i> is the default file processed by wsdl2h. Use <b>`wsdl2h -tfile.dat`</b>
244 option <b>`-tfile.dat`</b> to specify a different mapping file <i>`file.dat`</i>.
245
246 Declarations in <i>`typemap.dat`</i> can be broken up over multiple lines by
247 continuing on the next line by ending each line to be continued with a
248 backslash <b>`\`</b>. The limit is 4095 characters per line, whether the line is
249 broken up or not.
250
251 🔝 [Back to table of contents](#)
252
253 XML namespace bindings {#typemap1}
254 ----------------------
255
256 The wsdl2h tool generates C/C++ type declarations that use `ns1`, `ns2`, etc.
257 as schema-binding URI prefixes. These default prefixes are generated somewhat
258 arbitrarily for each schema targetNamespace URI, meaning that their ordering
259 may change depending on the WSDL and XSD order of processing with wsdl2h.
260
261 Therefore, it is **strongly recommended** to declare your own prefix for each
262 schema URI in <i>`typemap.dat`</i> to reduce maintaince effort of your code. This
263 is more robust when anticipating possible changes of the schema(s) and/or the
264 binding URI(s) and/or the tooling algorithms.
265
266 The first and foremost important thing to do is to define prefix-URI bindings
267 for our C/C++ code by adding the following line(s) to our <i>`typemap.dat`</i> or make
268 a copy of this file and add the line(s) that bind our choice of prefix name to
269 each URI:
270
271 prefix = "URI"
272
273 For example, to use `g` as a prefix for the "urn:graph" XML namespace:
274
275 g = "urn:graph"
276
277 This produces `g__name` C/C++ type names that are bound to the "urn:graph"
278 schema by association of `g` to the generated C/C++ types.
279
280 This means that <i>`<g:name xmlns:g="urn:graph">`</i> is parsed as an instance of a
281 `g__name` C/C++ type. Also <i>`<x:name xmlns:x="urn:graph">`</i> parses as an
282 instance of `g__name`, because the prefix <i>`x`</i> has the same URI value
283 <i>`urn:graph`</i>. Prefixes in XML have local scopes (like variables in a block).
284
285 The first run of wsdl2h will reveal the XML namespace URIs, so you do not need
286 to search WSDLs and XSD files for all of the target namespaces. Just copy them
287 from the generated header file after the first run into <i>`typemap.dat`</i> for
288 editing.
289
290 @note Only define a namespace prefix once in <i>`typemap.dat`</i>. That is, do not
291 use the same prefix for multiple XML namespace URIs. This is to avoid
292 namespace conflicts that may cause failed builds and failures in XML parsing
293 and XML schema validation.
294
295 🔝 [Back to table of contents](#)
296
297 XSD type bindings {#typemap2}
298 -----------------
299
300 Custom C/C++ type bindings can be declared in <i>`typemap.dat`</i> to associate C/C++
301 types with specific schema types. These type bindings have four parts:
302
303 prefix__type = declaration | use | ptruse
304
305 where
306
307 - <b>`prefix__type`</b> is the schema type to be customized (the <b>`prefix__type`</b> name
308 uses the common double underscore naming convention);
309
310 - <b>`declaration`</b> declares the C/C++ type in the wsdl2h-generated header file.
311 This part can be empty if no explicit declaration is needed;
312
313 - <b>`use`</b> is an optional part that specifies how the C/C++ type is used in the
314 code. When omitted, it is the same as <b>`prefix__type`</b>;
315
316 - <b>`ptruse`</b> is an optional part that specifies how the type is used as a pointer
317 type. By default it is the <b>`use`</b> type name with a <b>`*`</b> or C++11
318 <b>`std::shared_ptr<type>`</b> when enabled (see further below). If <b>`use`</b> is already a
319 pointer type by the presence of a <b>`*`</b> in the <b>`use`</b> part, then the default
320 <b>`ptruse`</b> type is the same as the <b>`use`</b> type (that is, no double
321 pointers <b>`**`</b> will be created in this case).
322
323 For example, to map <i>`xsd:duration`</i> to a `long long` (`LONG64`) type that holds
324 millisecond duration values, we can use the custom serializer declared in
325 <i>`gsoap/custom/duration.h`</i> by adding the following line to <i>`typemap.dat`</i>:
326
327 xsd__duration = #import "custom/duration.h"
328
329 Here, we omitted the second and third parts, because `xsd__duration` is the
330 name that wsdl2h uses for this type in our generated code so we should leave
331 the <b>`use`</b> part unspecified. The third part is omitted to let wsdl2h use
332 `xsd__duration *` for pointers or `std::shared_ptr<xsd__duration>` if smart
333 pointers are enabled.
334
335 To map <i>`xsd:string`</i> to `wchar_t*` wide strings for C source code output:
336
337 xsd__string = | wchar_t* | wchar_t*
338
339 For C++ we can use the `std::wstring` wide string:
340
341 xsd__string = | std::wstring
342
343 Note that the first part is empty, because these types do not require a
344 declaration. A <b>`ptruse`</b> part is also defined for `wchar_t*`, but this
345 is actually needed because the wsdl2h tool recognizes that the <b>`use`</b>
346 part `wchar_t*` is already a pointer. By contrast, when using 8-bit strings,
347 it is recommended to use the `SOAP_C_UTFSTRING` flag to enable UTF-8 formatted
348 strings.
349
350 When the auto-generated declaration should be preserved but the <b>`use`</b> or
351 <b>`ptruse`</b> parts replaced, then we use an ellipsis for the declaration part:
352
353 prefix__type = ... | use | ptruse
354
355 This is useful to map schema polymorphic types to C types for example, where we
356 need to be able to both handle a base type and its extensions as per schema
357 extensibility. Say we have a base type called <i>`ns:base`</i> that is extended, then
358 we can remap this to a C type that permits referening the extended types via a
359 `void*` as follows:
360
361 ns__base = ... | int __type_base; void*
362
363 such that `__type_base` and `void*` will be used to (de)serialize any data
364 type, including base and its derived types. The `__type_base` integer is set
365 to a `SOAP_TYPE_T` value to indicate what type of data the `void*` pointer
366 points to.
367
368 🔝 [Back to table of contents](#)
369
370 Custom serializers for XSD types {#custom}
371 --------------------------------
372
373 In the previous part we saw how a custom serializer is used to bind
374 <i>`xsd:duration`</i> to a `long long` (`LONG64` or `int64_t`) type to store millisecond
375 duration values:
376
377 xsd__duration = #import "custom/duration.h"
378
379 The `xsd__duration` type is an alias of `long long` (`LONG64` or `int64_t`).
380
381 While wsdl2h will use this binding declared in <i>`typemap.dat`</i>
382 automatically, you will also need to compile <i>`gsoap/custom/duration.c`</i>.
383 Each custom serializer has an interface header file to be imported into another
384 interface header file that declares the custom type for soapcpp2 and a
385 serializer implementation file written in C, which should be compiled with the
386 application. You can compile these in C++ (rename files to <i>`.cpp`</i> if
387 needed).
388
389 A custom serializer is declared in an interface header file for soapcpp2 using
390 `extern typedef`. The typedef name declared is serializable, whereas the
391 type on which it is based is not serializable. This declaration can be
392 combined with `volatile` when the type should not be redeclared, see
393 [volatile classes and structs](#toxsd9-2). For example, the custom serializer
394 for `struct tm` is the type `xsd__datetime` declared as follows in
395 `gsoap/custom/struct_tm.h`:
396
397 ~~~{.cpp}
398 extern typedef volatile struct tm
399 {
400 int tm_sec; ///< seconds (0 - 60)
401 int tm_min; ///< minutes (0 - 59)
402 int tm_hour; ///< hours (0 - 23)
403 int tm_mday; ///< day of month (1 - 31)
404 int tm_mon; ///< month of year (0 - 11)
405 int tm_year; ///< year - 1900
406 int tm_wday; ///< day of week (Sunday = 0) (NOT USED)
407 int tm_yday; ///< day of year (0 - 365) (NOT USED)
408 int tm_isdst; ///< is summer time in effect?
409 char* tm_zone; ///< abbreviation of timezone (NOT USED)
410 } xsd__dateTime;
411 ~~~
412
413 Another example is `xsd__duration` as a custom serializer for the C++11 type
414 `std::chrono::nanoseconds`:
415
416 ~~~{.cpp}
417 extern typedef class std::chrono::nanoseconds xsd__duration;
418 ~~~
419
420 Next, we present all pre-defined custom serializers that are available to you.
421
422 🔝 [Back to table of contents](#)
423
424 ### xsd:integer {#custom-1}
425
426 The wsdl2h tool maps <i>`xsd:integer`</i> to a string by default. To map <i>`xsd:integer`</i> to
427 the 128 bit big int type `__int128_t`:
428
429 xsd__integer = #import "custom/int128.h"
430
431 The `xsd__integer` type is an alias of `__int128_t`.
432
433 @warning Beware that the <i>`xsd:integer`</i> value space of integers is in principle
434 unbounded and values can be of arbitrary length. A value range fault
435 `SOAP_TYPE` (value exceeds native representation) or `SOAP_LENGTH` (value
436 exceeds range bounds) will be thrown by the deserializer if the value is out of
437 range.
438
439 Other XSD integer types that are restrictions of <i>`xsd:integer`</i>, are
440 <i>`xsd:nonNegativeInteger`</i> and <i>`xsd:nonPositiveInteger`</i>, which are further restricted
441 by <i>`xsd:positiveInteger`</i> and <i>`xsd:negativeInteger`</i>. To bind these types to
442 `__int128_t` add the following definitions to <i>`typemap.dat`</i>:
443
444 xsd__nonNegativeInteger = typedef xsd__integer xsd__nonNegativeInteger 0 : ;
445 xsd__nonPositiveInteger = typedef xsd__integer xsd__nonPositiveInteger : 0 ;
446 xsd__positiveInteger = typedef xsd__integer xsd__positiveInteger 1 : ;
447 xsd__negativeInteger = typedef xsd__integer xsd__negativeInteger : -1 ;
448
449 Or simply uncomment these definitions in <i>`typemap.dat`</i> when you are using the
450 latest gSOAP releases.
451
452 @note If `__int128_t` 128 bit integers are not supported on your platform and if it
453 is certain that <i>`xsd:integer`</i> values are within 64 bit value bounds for your
454 application's use, then you can map this type to `LONG64`:
455
456 xsd__integer = typedef LONG64 xsd__integer;
457
458 @note Again, a value range fault `SOAP_TYPE` or `SOAP_LENGTH` will be thrown by
459 the deserializer if the value is out of range.
460
461 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/int128.c`</i> with your project.
462
463 @see Section [numerical types](#toxsd5).
464
465 🔝 [Back to table of contents](#)
466
467 ### xsd:decimal {#custom-2}
468
469 The wsdl2h tool maps <i>`xsd:decimal`</i> to a string by default. To map <i>`xsd:decimal`</i> to
470 extended precision floating point:
471
472 xsd__decimal = #import "custom/long_double.h" | long double
473
474 By contrast to all other custom serializers, this serializer enables `long
475 double` natively without requiring a new binding name (`xsd__decimal` is NOT
476 defined).
477
478 If your system supports <i>`quadmath.h`</i> quadruple precision floating point
479 `__float128`, you can map <i>`xsd:decimal`</i> to `xsd__decimal` that is an alias of
480 `__float128`:
481
482 xsd__decimal = #import "custom/float128.h"
483
484 @warning Beware that <i>`xsd:decimal`</i> is in principle a decimal value with arbitraty
485 lengths. A value range fault `SOAP_TYPE` will be thrown by the deserializer if
486 the value is out of range.
487
488 In the XML payload the special values <i>`INF`</i>, <i>`-INF`</i>, <i>`NaN`</i>
489 represent plus or minus infinity and not-a-number, respectively.
490
491 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/long_double.c`</i> with your
492 project.
493
494 @see Section [numerical types](#toxsd5).
495
496 🔝 [Back to table of contents](#)
497
498 ### xsd:dateTime {#custom-3}
499
500 The wsdl2h tool maps <i>`xsd:dateTime`</i> to `time_t` by default.
501
502 The trouble with `time_t` when represented as 32 bit `long` integers is that it
503 is limited to dates between 1970 and 2038. A 64 bit `time_t` is safe to use if
504 the target platform supports it, but lack of 64 bit `time_t` portability may
505 still cause date range issues.
506
507 For this reason `struct tm` should be used to represent wider date ranges. This
508 custom serializer avoids using date and time information in `time_t`. You get
509 the raw date and time information. You only lose the day of the week
510 information. It is always Sunday (`tm_wday=0`).
511
512 To map <i>`xsd:dateTime`</i> to `xsd__dateTime` which is an alias of `struct tm`:
513
514 xsd__dateTime = #import "custom/struct_tm.h"
515
516 If the limited date range of `time_t` is not a problem but you want to increase
517 the time precision with fractional seconds, then we suggest to map <i>`xsd:dateTime`</i>
518 to `struct timeval`:
519
520 xsd__dateTime = #import "custom/struct_timeval.h"
521
522 If the limited date range of `time_t` is not a problem but you want to use the
523 C++11 time point type `std::chrono::system_clock::time_point` (which internally
524 uses `time_t`):
525
526 xsd__dateTime = #import "custom/chrono_time_point.h"
527
528 Again, we should make sure that the dates will not exceed the date range when
529 using the default `time_t` binding for <i>`xsd:dateTime`</i> or when binding
530 <i>`xsd:dateTime`</i> to `struct timeval` or to `std::chrono::system_clock::time_point`.
531 These are safe to use in applications that use <i>`xsd:dateTime`</i> to record date
532 stamps within a given window. Otherwise, we recommend the `struct tm` custom
533 serializer.
534
535 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/struct_tm.c`</i> with your
536 project.
537
538 You could even map <i>`xsd:dateTime`</i> to a plain string (use `char*` with C and
539 `std::string` with C++). For example:
540
541 xsd__dateTime = | char*
542
543 @see Section [date and time types](#toxsd7).
544
545 🔝 [Back to table of contents](#)
546
547 ### xsd:date {#custom-4}
548
549 The wsdl2h tool maps <i>`xsd:date`</i> to a string by default. We can map <i>`xsd:date`</i> to
550 `struct tm`:
551
552 xsd__date = #import "custom/struct_tm_date.h"
553
554 The `xsd__date` type is an alias of `struct tm`. The serializer ignores the
555 time part and the deserializer only populates the date part of the struct,
556 setting the time to 00:00:00. There is no unreasonable limit on the date range
557 because the year field is stored as an integer (`int`).
558
559 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/struct_tm_date.c`</i> with your
560 project.
561
562 @see Section [date and time types](#toxsd7).
563
564 🔝 [Back to table of contents](#)
565
566 ### xsd:time {#custom-5}
567
568 The wsdl2h tool maps <i>`xsd:time`</i> to a string by default. We can map <i>`xsd:time`</i> to
569 an `unsigned long long` (`ULONG64` or `uint64_t`) integer with microsecond time
570 precision:
571
572 xsd__time = #import "custom/long_time.h"
573
574 This type represents 00:00:00.000000 to 23:59:59.999999, from `0` to an upper
575 bound of `86399999999`. A microsecond resolution means that a 1 second
576 increment requires an increment of 1000000 in the integer value. The serializer
577 adds a UTC time zone.
578
579 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/long_time.c`</i> with your
580 project.
581
582 @see Section [date and time types](#toxsd7).
583
584 🔝 [Back to table of contents](#)
585
586 ### xsd:duration {#custom-6}
587
588 The wsdl2h tool maps <i>`xsd:duration`</i> to a string by default, unless <i>`xsd:duration`</i>
589 is mapped to a `long long` (`LONG64` or `int64_t`) type with with millisecond
590 (ms) time duration precision:
591
592 xsd__duration = #import "custom/duration.h"
593
594 The `xsd__duration` type is a 64 bit signed integer that can represent
595 106,751,991,167 days forwards (positive) and backwards (negative) in time in
596 increments of 1 ms (1/1000 of a second).
597
598 Rescaling of the duration value by may be needed when adding the duration value
599 to a `time_t` value, because `time_t` may or may not have a seconds resolution,
600 depending on the platform and possible changes to `time_t`.
601
602 Rescaling is done automatically when you add a C++11 `std::chrono::nanoseconds`
603 value to a `std::chrono::system_clock::time_point` value. To use
604 `std::chrono::nanoseconds` as <i>`xsd:duration`</i>:
605
606 xsd__duration = #import "custom/chrono_duration.h"
607
608 This type can represent 384,307,168 days (2^63 nanoseconds) forwards and
609 backwards in time in increments of 1 ns (1/1,000,000,000 of a second).
610
611 Certain observations with respect to receiving durations in years and months
612 apply to both of these serializer decoders for <i>`xsd:duration`</i>.
613
614 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/duration.c`</i> with your
615 project.
616
617 @see Section [time duration types](#toxsd8).
618
619 🔝 [Back to table of contents](#)
620
621 Custom Qt serializers for XSD types {#qt}
622 -----------------------------------
623
624 The gSOAP distribution includes several custom serializers for Qt types. Also
625 Qt container classes are supported, see
626 [the built-in typemap.dat variables $CONTAINER, $POINTER and $SIZE](#typemap5).
627
628 This feature requires gSOAP 2.8.34 or higher and Qt 4.8 or higher.
629
630 Each Qt custom serializer has an interface header file for soapcpp2 and a C++
631 implementation file to be compiled with your project.
632
633 Other Qt primitive types that are Qt `typedef`s of C/C++ types do not require a
634 custom serializer.
635
636 🔝 [Back to table of contents](#)
637
638 ### xsd:string {#qt-1}
639
640 To use Qt strings instead of C++ strings, add the following definition to
641 <i>`typemap.dat`</i>:
642
643 xsd__string = #import "custom/qstring.h"
644
645 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qstring.cpp`</i> with your
646 project.
647
648 🔝 [Back to table of contents](#)
649
650 ### xsd:base64Binary {#qt-2}
651
652 To use Qt byte arrays for <i>`xsd:base64Binary`</i> instead of the
653 `xsd__base64Binary` class, add the following definition to <i>`typemap.dat`</i>:
654
655 xsd__base64Binary = #import "custom/qbytearray_base64.h"
656
657 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qbytearray_base64.cpp`</i> with
658 your project.
659
660 🔝 [Back to table of contents](#)
661
662 ### xsd:hexBinary {#qt-3}
663
664 To use Qt byte arrays for <i>`xsd:hexBinary`</i> instead of the `xsd__base64Binary`
665 class, add the following definition to <i>`typemap.dat`</i>:
666
667 xsd__hexBinary = #import "custom/qbytearray_hex.h"
668
669 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qbytearray_hex.cpp`</i> with
670 your project.
671
672 🔝 [Back to table of contents](#)
673
674 ### xsd:dateTime {#qt-4}
675
676 To use Qt QDateTime for <i>`xsd:dateTime`</i>, add the following definition to
677 <i>`typemap.dat`</i>:
678
679 xsd__dateTime = #import "custom/datetime.h"
680
681 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qdatetime.cpp`</i> with
682 your project.
683
684 🔝 [Back to table of contents](#)
685
686 ### xsd:date {#qt-5}
687
688 To use Qt QDate for <i>`xsd:date`</i>, add the following definition to
689 <i>`typemap.dat`</i>:
690
691 xsd__date = #import "custom/qdate.h"
692
693 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qdate.cpp`</i> with your
694 project.
695
696 🔝 [Back to table of contents](#)
697
698 ### xsd:time {#qt-6}
699
700 To use Qt QDate for <i>`xsd:time`</i>, add the following definition to
701 <i>`typemap.dat`</i>:
702
703 xsd__time = #import "custom/qtime.h"
704
705 After running wsdl2h and soapcpp2, compile <i>`gsoap/custom/qtime.cpp`</i> with your
706 project.
707
708 🔝 [Back to table of contents](#)
709
710 Class/struct member additions {#typemap3}
711 -----------------------------
712
713 All generated classes and structs can be augmented with additional
714 members such as methods, constructors and destructors, and private members:
715
716 prefix__type = $ member-declaration
717
718 For example, we can add method declarations and private members to a class, say
719 `ns__record` as follows:
720
721 ns__record = $ ns__record(const ns__record &); // copy constructor
722 ns__record = $ void print(); // a print method
723 ns__record = $ private: int status; // a private member
724
725 Method declarations cannot include any code, because soapcpp2's input permits
726 only type declarations, not code.
727
728 🔝 [Back to table of contents](#)
729
730 Replacing XSD types by equivalent alternatives {#typemap4}
731 ----------------------------------------------
732
733 Type replacements can be given to replace one type entirely with another given
734 type:
735
736 prefix__type1 == prefix__type2
737
738 This replaces all `prefix__type1` by `prefix__type2` in the wsdl2h output.
739
740 @warning Do not agressively replace types, because this can cause XML schema
741 validation to fail when a value-type mismatch is encountered in the XML input.
742 Therefore, only replace similar types with other similar types that are wider
743 (e.g. `short` by `int` and `float` by `double`).
744
745 🔝 [Back to table of contents](#)
746
747 The built-in typemap.dat variables $CONTAINER, $POINTER and $SIZE {#typemap5}
748 -----------------------------------------------------------------
749
750 The <i>`typemap.dat`</i> <b>`$CONTAINER`</b> variable defines the container type to use in
751 the wsdl2h-generated declarations for C++, which is `std::vector` by default.
752 For example, to use `std::list` as the container in the wsdl2h-generated
753 declarations we add the following line to <i>`typemap.dat`</i>:
754
755 $CONTAINER = std::list
756
757 Also a Qt container can be used instead of the default `std::vector`, for
758 example `QVector`:
759
760 [
761 #include <QVector>
762 ]
763 $CONTAINER = QVector
764
765 To remove containers, use <b>`wsdl2h -s`</b>. This also removes `std::string`,
766 but you can re-introduce `std::string` with
767 <b>`xsd__string = | std::string`</b> in <i>`typemap.dat`</i>.
768
769 The <i>`typemap.dat`</i> <b>`$POINTER`</b> variable defines the smart pointer to use in the
770 wsdl2h-generated declarations for C++, which replaces the use of `*` pointers.
771 For example:
772
773 $POINTER = std::shared_ptr
774
775 Not all pointers in the generated output are replaced by smart pointers by
776 wsdl2h, such as pointers as union members and pointers as struct/class members
777 that point to arrays of values.
778
779 @note The standard smart pointer `std::shared_ptr` is generally safe to use.
780 Other smart pointers such as `std::unique_ptr` and `std::auto_ptr` may cause
781 compile-time errors when classes have smart pointer members but no copy
782 constructor (a default copy constructor). A copy constructor is required for
783 non-shared smart pointer copying or swapping.
784
785 Alternatives to `std::shared_ptr` of the form `NAMESPACE::shared_ptr` can be
786 assigned to <b>`$POINTER`</b> when the namespace `NAMESPACE` also implements
787 `NAMESPACE::make_shared` and when the shared pointer class provides `reset()`
788 and`get()` methods and the dereference operator. For example Boost
789 `boost::shared_ptr`:
790
791 [
792 #include <boost/shared_ptr.hpp>
793 ]
794 $POINTER = boost::shared_ptr
795
796 The user-defined content between <b>`[`</b> and <b>`]`</b> ensures that we include the Boost
797 header files that are needed to support `boost::shared_ptr` and
798 `boost::make_shared`.
799
800 The variable <b>`$SIZE`</b> defines the type of array sizes, which is `int` by
801 default. For example, to change array size types to `size_t`:
802
803 $SIZE = size_t
804
805 Permissible types are `int` and `size_t`. This variable does not affect the
806 size of dynamic arrays, `xsd__hexBinary` and `xsd__base64Binary` types, which
807 is always `int`.
808
809 🔝 [Back to table of contents](#)
810
811 User-defined content {#typemap6}
812 --------------------
813
814 Any other content to be generated by wsdl2h can be included in <i>`typemap.dat`</i> by
815 enclosing it within brackets <b>`[`</b> and <b>`]`</b> anywhere in the <i>`typemap.dat`</i> file.
816 Each of the two brackets must appear at the start of a new line.
817
818 For example, we can add an `#import "wsa5.h"` to the wsdl2h-generated output as
819 follows:
820
821 [
822 #import "import/wsa5.h"
823 ]
824
825 which emits the `#import "import/wsa5.h"` literally at the start of the
826 wsdl2h-generated header file.
827
828 🔝 [Back to table of contents](#)
829
830 Mapping C/C++ to XML schema {#toxsd}
831 ===========================
832
833 The soapcpp2 command generates the data binding implementation code from a data
834 binding interface <i>`file.h`</i>:
835
836 soapcpp2 [options] file.h
837
838 where <i>`file.h`</i> is a interface header file that declares the XML data
839 binding interface. The <i>`file.h`</i> is typically generated by wsdl2h, but
840 you can also declare one yourself. If so, add `//gsoap`
841 [directives](#directives) and declare in this file all our C/C++ types you want
842 to serialize in XML.
843
844 You can also declare functions that will be converted to Web service operations
845 by soapcpp2. Global function declarations define service operations, which are
846 of the form:
847
848 ~~~{.cpp}
849 int prefix__func(arg1, arg2, ..., argn, result);
850 ~~~
851
852 where `arg1`, `arg2`, ..., `argn` are formal argument declarations of the input
853 and `result` is a formal argument for the output, which must be a pointer or
854 reference to the result object to be populated. More information on declaring
855 and implementing service operation functions can be found in the
856 [gSOAP user guide.](../../guide/html/index.html)
857
858 🔝 [Back to table of contents](#)
859
860 Overview of serializable C/C++ types {#toxsd1}
861 ------------------------------------
862
863 The following C/C++ types are supported by soapcpp2 and mapped to XSD types
864 and constructs. See the subsections below for more details or follow the links.
865
866 🔝 [Back to table of contents](#)
867
868 ### List of Boolean types
869
870 Boolean Type | Notes
871 ----------------------------- | -----
872 `bool` | C++ bool
873 `enum xsd__boolean` | C alternative to C++ `bool` with `false_` and `true_`
874
875 @see Section [C++ bool and C alternative](#toxsd3).
876
877 🔝 [Back to table of contents](#)
878
879 ### List of enumeration and bitmask types
880
881 Enumeration Type | Notes
882 ----------------------------- | -----
883 `enum` | enumeration
884 `enum class` | C++11 scoped enumeration, requires `soapcpp2 -c++11`
885 `enum*` | a bitmask that enumerates values 1, 2, 4, 8, ...
886 `enum* class` | C++11 scoped enumeration bitmask, requires `soapcpp2 -c++11`
887
888 @see Section [enumerations and bitmasks](#toxsd4).
889
890 🔝 [Back to table of contents](#)
891
892 ### List of numerical types
893
894 Numerical Type | Notes
895 ----------------------------- | -----
896 `char` | byte
897 `short` | 16 bit integer
898 `int` | 32 bit integer
899 `long` | 32 bit integer
900 `LONG64` | 64 bit integer
901 `xsd__integer` | 128 bit integer, use `#import "custom/int128.h"`
902 `long long` | same as `LONG64`
903 `unsigned char` | unsigned byte
904 `unsigned short` | unsigned 16 bit integer
905 `unsigned int` | unsigned 32 bit integer
906 `unsigned long` | unsigned 32 bit integer
907 `ULONG64` | unsigned 64 bit integer
908 `unsigned long long` | same as `ULONG64`
909 `int8_t` | same as `char`
910 `int16_t` | same as `short`
911 `int32_t` | same as `int`
912 `int64_t` | same as `LONG64`
913 `uint8_t` | same as `unsigned char`
914 `uint16_t` | same as `unsigned short`
915 `uint32_t` | same as `unsigned int`
916 `uint64_t` | same as `ULONG64`
917 `size_t` | transient type (not serializable)
918 `float` | 32 bit float
919 `double` | 64 bit float
920 `long double` | extended precision float, use `#import "custom/long_double.h"`
921 `xsd__decimal` | `quadmath.h` library 128 bit quadruple precision float, use `#import "custom/float128.h"`
922 `typedef` | declares a type name, with optional value range and string length bounds
923
924 @see Section [numerical types](#toxsd5).
925
926 🔝 [Back to table of contents](#)
927
928 ### List of string types
929
930 String Type | Notes
931 ----------------------------- | -----
932 `char*` | string (may contain UTF-8 with flag `SOAP_C_UTFSTRING`)
933 `wchar_t*` | wide string
934 `std::string` | C++ string (may contain UTF-8 with flag `SOAP_C_UTFSTRING`)
935 `std::wstring` | C++ wide string
936 `char[N]` | fixed-size string, requires `soapcpp2 -b`
937 `_QName` | normalized QName content
938 `_XML` | literal XML string content with wide characters in UTF-8
939 `typedef` | declares a new string type name, may restrict string length
940
941 @see Section [string types](#toxsd6).
942
943 🔝 [Back to table of contents](#)
944
945 ### List of date and time types
946
947 Date and Time Type | Notes
948 --------------------------------------- | -----
949 `time_t` | date and time point since epoch
950 `struct tm` | date and time point, use `#import "custom/struct_tm.h"`
951 `struct tm` | date point, use `#import "custom/struct_tm_date.h"`
952 `struct timeval` | date and time point, use `#import "custom/struct_timeval.h"`
953 `unsigned long long` | time point in microseconds, use `#import "custom/long_time.h"`
954 `std::chrono::system_clock::time_point` | date and time point, use `#import "custom/chrono_time_point.h"`
955
956 @see Section [date and time types](#toxsd7).
957
958 🔝 [Back to table of contents](#)
959
960 ### List of time duration types
961
962 Time Duration Type | Notes
963 ----------------------------- | -----
964 `long long` | duration in milliseconds, use `#import "custom/duration.h"`
965 `std::chrono::nanoseconds` | duration in nanoseconds, use `#import "custom/chrono_duration.h"`
966
967 @see Section [time duration types](#toxsd8).
968
969 🔝 [Back to table of contents](#)
970
971 ### List of classes, structs, unions, pointers, containers, and arrays
972
973 Classes, Structs, and Members | Notes
974 ----------------------------- | -----
975 `class` | C++ class with single inheritance only
976 `struct` | C struct or C++ struct without inheritance
977 `std::shared_ptr<T>` | C++11 smart shared pointer
978 `std::unique_ptr<T>` | C++11 smart pointer
979 `std::auto_ptr<T>` | C++ smart pointer
980 `std::deque<T>` | use `#import "import/stldeque.h"`
981 `std::list<T>` | use `#import "import/stllist.h"`
982 `std::vector<T>` | use `#import "import/stlvector.h"`
983 `std::set<T>` | use `#import "import/stlset.h"`
984 `template<T> class` | a container with `begin()`, `end()`, `size()`, `clear()`, and `insert()` methods
985 `T*` | pointer to data of type `T`
986 `T*` | as a class or struct member: points to data of type `T` or array of `T` with member `__size`
987 `T[N]` | as a class or struct member: fixed-size array of type `T`
988 `union` | as a class or struct member: requires a variant selector member `__union`
989 `void*` | as a class or struct member: requires a `__type` member to indicate the type of object pointed to
990
991 @see Section [classes and structs](#toxsd9).
992
993 🔝 [Back to table of contents](#)
994
995 ### List of special classes and structs
996
997 Special Classes and Structs | Notes
998 ----------------------------- | -----
999 Special Array class/struct | single and multidimensional SOAP Arrays
1000 Special Wrapper class/struct | complexTypes with simpleContent, wraps `__item` member
1001 `xsd__hexBinary` | binary content
1002 `xsd__base64Binary` | binary content and optional DIME/MIME/MTOM attachments
1003 `xsd__anyType` | DOM elements, use `#import "dom.h"`
1004 `@xsd__anyAttribute` | DOM attributes, use `#import "dom.h"`
1005
1006 @see Section [special classes and structs](#toxsd10).
1007
1008 🔝 [Back to table of contents](#)
1009
1010 Colon notation versus name prefixing with XML tag name translation {#toxsd2}
1011 ------------------------------------------------------------------
1012
1013 To bind C/C++ type names to XSD types, a simple form of name prefixing is used
1014 by the gSOAP tools by prepending the XML namespace prefix to the C/C++ type
1015 name with a pair of undescrores. This also ensures that name clashes cannot
1016 occur when multiple WSDL and XSD files are converted to C/C++. Also, C++
1017 namespaces are not sufficiently rich to capture XML schema namespaces
1018 accurately, for example when class members are associated with schema elements
1019 defined in another XML namespace and thus the XML namespace scope of the
1020 member's name is relevant, not just its type.
1021
1022 However, from a C/C++ centric point of view this can be cumbersome. Therefore,
1023 colon notation is an alternative to physically augmenting C/C++ names with
1024 prefixes.
1025
1026 For example, the following class uses colon notation to bind the `record` class
1027 to the <i>`urn:types`</i> schema:
1028
1029 ~~~{.cpp}
1030 //gsoap ns schema namespace: urn:types
1031 class ns:record // binding 'ns:' to a type name
1032 {
1033 public:
1034 std::string name;
1035 uint64_t SSN;
1036 ns:record *spouse; // using 'ns:' with the type name
1037 ns:record(); // using 'ns:' here too
1038 ~ns:record(); // and here
1039 };
1040 ~~~
1041
1042 The colon notation is stripped away by soapcpp2 when generating the data
1043 binding implementation code for our project. So the final code just uses
1044 `record` to identify this class and its constructor/destructor.
1045
1046 When using colon notation make sure to be consistent and not use colon notation
1047 mixed with prefixed forms. The qualified name `ns:record` differs from `ns__record`,
1048 because `ns:record` is compiled to an unqualified `record` name in the source
1049 code output by the soapcpp2 tool.
1050
1051 Colon notation also facilitates overruling the elementFormDefault and
1052 attributeFormDefault declaration that is applied to local elements and
1053 attributes, when declared as members of classes, structs, and unions. For more
1054 details, see [qualified and unqualified members](#toxsd9-6).
1055
1056 A C/C++ identifier name (a type name, member name, function name, or parameter
1057 name) is translated to an XML tag name by the following rules:
1058
1059 - Two leading underscores indicates that the identifier name has no XML tag
1060 name, i.e. this name is not visible in XML and is not translated.
1061
1062 - A leading underscore is removed, but the underscore indicates that: **a**) a
1063 struct/class member name or parameter name has a wildcard XML tag name (i.e.
1064 matches any XML tag), or **b**) a type name that has a
1065 [document root element definition](#toxsd9-7).
1066
1067 - Trailing underscores are removed (i.e. trailing underscores can be used to
1068 avoid name clashes with keywords).
1069
1070 - Underscores within names are translated to hyphens (hyphens are more common
1071 in XML tag names).
1072
1073 - `_USCORE` is translated to an underscore in the translated XML tag name.
1074
1075 - `_DOT` is translated to a dot (<i>`.`</i>) in the translated XML tag name.
1076
1077 - `_xHHHH` is translated to the Unicode character with code point HHHH (hex).
1078
1079 - C++11 Unicode identifier name characters in UTF-8 are translated as-is.
1080
1081 For example, the C/C++ namespace qualified identifier name `s_a__my_way` is
1082 translated to the XML tag name <i>`s-a:my-way`</i> by translating the prefix `s_a`
1083 and the local name `my_way`.
1084
1085 Struct/class member and parameter name translation can be overruled by using
1086 [backtick XML tags](#toxsd9-5-1) (with gSOAP 2.8.30 and greater).
1087
1088 🔝 [Back to table of contents](#)
1089
1090 C++ bool and C alternative {#toxsd3}
1091 --------------------------
1092
1093 The C++ `bool` type is bound to built-in XSD type <i>`xsd:boolean`</i>.
1094
1095 The C alternative is to define an enumeration:
1096
1097 ~~~{.cpp}
1098 enum xsd__boolean { false_, true_ };
1099 ~~~
1100
1101 or by defining an enumeration in C with pseudo-scoped enumeration constants:
1102
1103 ~~~{.cpp}
1104 enum xsd__boolean { xsd__boolean__false, xsd__boolean__true };
1105 ~~~
1106
1107 The XML value space of these types is <i>`false`</i> and <i>`true`</i>, but also accepted
1108 are <i>`0`</i> and <i>`1`</i> values for <i>`false`</i> and <i>`true`</i>, respectively.
1109
1110 To prevent name clashes, `false_` and `true_` have a trailing underscore in
1111 their `enum` symbols. Trailing underscores are removed from the XML value space.
1112
1113 🔝 [Back to table of contents](#)
1114
1115 Enumerations and bitmasks {#toxsd4}
1116 -------------------------
1117
1118 Enumerations are mapped to XSD simpleType enumeration restrictions of
1119 <i>`xsd:string`</i>, <i>`xsd:QName`</i>, and <i>`xsd:long`</i>.
1120
1121 Consider for example:
1122
1123 ~~~{.cpp}
1124 enum ns__Color { RED, WHITE, BLUE };
1125 ~~~
1126
1127 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1128 schema:
1129
1130 <div class="alt">
1131 ~~~{.xml}
1132 <simpleType name="Color">
1133 <restriction base="xsd:string">
1134 <enumeration value="RED"/>
1135 <enumeration value="WHITE"/>
1136 <enumeration value="BLUE"/>
1137 </restriction>
1138 </simpleType>
1139 ~~~
1140 </div>
1141
1142 Enumeration name constants can be pseudo-scoped to prevent name clashes,
1143 because enumeration name constants have a global scope in C and C++:
1144
1145 ~~~{.cpp}
1146 enum ns__Color { ns__Color__RED, ns__Color__WHITE, ns__Color__BLUE };
1147 ~~~
1148
1149 You can also use C++11 scoped enumerations to prevent name clashes:
1150
1151 ~~~{.cpp}
1152 enum class ns__Color : int { RED, WHITE, BLUE };
1153 ~~~
1154
1155 Here, the enumeration class base type `: int` is optional. In place of `int`
1156 in the example above, we can also use `int8_t`, `int16_t`, `int32_t`, or
1157 `int64_t`.
1158
1159 The XML value space of the enumertions defined above is <i>`RED`</i>, <i>`WHITE`</i>, and
1160 <i>`BLUE`</i>.
1161
1162 Prefix-qualified enumeration name constants are mapped to simpleType
1163 restrictions of <i>`xsd:QName`</i>, for example:
1164
1165 ~~~{.cpp}
1166 enum ns__types { xsd__int, xsd__float };
1167 ~~~
1168
1169 which maps to a simpleType restriction of <i>`xsd:QName`</i> in the soapcpp2-generated
1170 schema:
1171
1172 <div class="alt">
1173 ~~~{.xml}
1174 <simpleType name="types">
1175 <restriction base="xsd:QName">
1176 <enumeration value="xsd:int"/>
1177 <enumeration value="xsd:float"/>
1178 </restriction>
1179 </simpleType>
1180 ~~~
1181 </div>
1182
1183 Enumeration name constants can be pseudo-numeric as follows:
1184
1185 ~~~{.cpp}
1186 enum ns__Primes { _3 = 3, _5 = 5, _7 = 7, _11 = 11 };
1187 ~~~
1188
1189 which maps to a simpleType restriction of <i>`xsd:long`</i>:
1190
1191 <div class="alt">
1192 ~~~{.xml}
1193 <simpleType name="Color">
1194 <restriction base="xsd:long">
1195 <enumeration value="3"/>
1196 <enumeration value="5"/>
1197 <enumeration value="7"/>
1198 <enumeration value="11"/>
1199 </restriction>
1200 </simpleType>
1201 ~~~
1202 </div>
1203
1204 The XML value space of this type is <i>`3`</i>, <i>`5`</i>, <i>`7`</i>, and <i>`11`</i>.
1205
1206 Besides (pseudo-) scoped enumerations, another way to prevent name clashes
1207 accross enumerations is to start an enumeration name constant with one
1208 underscore or followed it by any number of underscores, which makes it
1209 unique. The leading and trailing underscores are removed from the XML value
1210 space.
1211
1212 ~~~{.cpp}
1213 enum ns__ABC { A, B, C };
1214 enum ns__BA { B, A }; // BAD: B = 1 but B is already defined as 2
1215 enum ns__BA_ { B_, A_ }; // OK
1216 ~~~
1217
1218 The gSOAP soapcpp2 tool permits reusing enumeration name constants across
1219 (non-scoped) enumerations as long as these values are assigned the same
1220 constant. Therefore, the following is permitted:
1221
1222 ~~~{.cpp}
1223 enum ns__Primes { _3 = 3, _5 = 5, _7 = 7, _11 = 11 };
1224 enum ns__Throws { _1 = 1, _2 = 2, _3 = 3, _4 = 4, _5 = 5, _6 = 6 };
1225 ~~~
1226
1227 A bitmask type is an `enum*` "product enumeration" with a geometric,
1228 power-of-two sequence of values assigned to the enumeration constants:
1229
1230 ~~~{.cpp}
1231 enum* ns__Options { SSL3, TLS10, TLS11, TLS12, TLS13 };
1232 ~~~
1233
1234 where the product enum assigns 1 to `SSL3`, 2 to `TLS10`, 4 to `TLS11`, 8
1235 to `TLS12`, and 16 to `TLS13`, which allows these enumeration constants to be
1236 used in composing bitmasks with `|` (bitwise or) `&` (bitwise and), and `~`
1237 (bitwise not):
1238
1239 ~~~{.cpp}
1240 enum ns__Options options = (enum ns__Options)(SSL3 | TLS10 | TLS11 | TLS12 | TLS13);
1241 if (options & SSL3) // if SSL3 is an option, warn and remove from options
1242 {
1243 warning();
1244 options &= ~SSL3;
1245 }
1246 ~~~
1247
1248 The bitmask type maps to a simpleType list restriction of <i>`xsd:string`</i> in the
1249 soapcpp2-generated XML schema:
1250
1251 <div class="alt">
1252 ~~~{.xml}
1253 <simpleType name="Options">
1254 <list>
1255 <restriction base="xsd:string">
1256 <enumeration value="SSL3"/>
1257 <enumeration value="TLS10"/>
1258 <enumeration value="TLS11"/>
1259 <enumeration value="TLS12"/>
1260 <enumeration value="TLS13"/>
1261 </restriction>
1262 </list>
1263 </simpleType>
1264 ~~~
1265 </div>
1266
1267 The XML value space of this type consists of all 16 possible subsets of the
1268 four values, represented by an XML string with space-separated values. For
1269 example, the bitmask `TLS10 | TLS11 | TLS12` equals 14 and is represented by
1270 the XML text <i>`TLS10 TLS11 TLS12`</i>.
1271
1272 You can also use C++11 scoped enumerations with bitmasks using `enum*` product
1273 enumerations:
1274
1275 ~~~{.cpp}
1276 enum* class ns__Options { SSL3, TLS10, TLS11, TLS12, TLS13 };
1277 ~~~
1278
1279 The base type of a scoped enumeration bitmask, when explicitly given, is
1280 ignored. The base type is either `int` or `int64_t`, depending on the number
1281 of constants enumerated in the bitmask.
1282
1283 To convert `enum` name constants and bitmasks to a string, we use the
1284 auto-generated function for enum `T`:
1285
1286 ~~~{.cpp}
1287 const char *soap_T2s(struct soap*, enum T val)
1288 ~~~
1289
1290 The string returned is stored in an internal buffer of the current `soap`
1291 context, so you should copy it to keep it from being overwritten. For example,
1292 use `char *soap_strdup(struct soap*, const char*)`.
1293
1294 To convert a string to an `enum` constant or bitmask, we use the auto-generated
1295 function
1296
1297 ~~~{.cpp}
1298 int soap_s2T(struct soap*, const char *str, enum T *val)
1299 ~~~
1300
1301 This function takes the name (or names, space-separated for bitmasks) of
1302 the enumeration constant in a string `str`. Names should be given without the
1303 pseudo-scope prefix and without trailing underscores. The function sets `val`
1304 to the corresponding integer enum constant or to a bitmask. The function
1305 returns `SOAP_OK` (zero) on success or an error if the string is not a valid
1306 enumeration name.
1307
1308 🔝 [Back to table of contents](#)
1309
1310 Numerical types {#toxsd5}
1311 ---------------
1312
1313 Integer and floating point types are mapped to the equivalent built-in XSD
1314 types with the same sign and bit width.
1315
1316 The `size_t` type is transient (not serializable) because its width is platform
1317 dependent. We recommend to use `uint64_t` instead.
1318
1319 The XML value space of integer types are their decimal representations without
1320 loss of precision.
1321
1322 The XML value space of floating point types are their decimal representations.
1323 The decimal representations are formatted with the printf format string `"%.9G"`
1324 for floats and the printf format string `"%.17lG"` for double. To change the
1325 format strings, we can assign new strings to the following `soap` context
1326 members:
1327
1328 ~~~{.cpp}
1329 soap.float_format = "%g";
1330 soap.double_format = "%lg";
1331 soap.long_double_format = "%Lg";
1332 ~~~
1333
1334 Decimal representations may result in a loss of precision of the least
1335 significant decimal. Therefore, the format strings that are used by default
1336 are sufficiently precise to avoid loss, but this may result in long decimal
1337 fractions in the XML value space.
1338
1339 The `long double` extended floating point type requires a custom serializer:
1340
1341 ~~~{.cpp}
1342 #import "custom/long_double.h"
1343 ... // use long double
1344 ~~~
1345
1346 You can now use `long double`, which has a serializer that serializes this type
1347 as <i>`xsd:decimal`</i>. Compile and link your code with the file
1348 <i>`gsoap/custom/long_double.c`</i>.
1349
1350 The value space of floating point values includes the special values
1351 <i>`INF`</i>, <i>`-INF`</i>, and <i>`NaN`</i>. You can check a value for plus
1352 or minus infinity and not-a-number as follows:
1353
1354 ~~~{.cpp}
1355 soap_isinf(x) && x > 0 // is x INF?
1356 soap_isinf(x) && x < 0 // is x -INF?
1357 soap_isnan(x) // is x NaN?
1358 ~~~
1359
1360 To assign these values, use:
1361
1362 ~~~{.cpp}
1363 // x is float // x is double, long double, or __float128
1364 x = FLT_PINFY; x = DBL_PINFTY;
1365 x = FLT_NINFY; x = DBL_NINFTY;
1366 x = FLT_NAN; x = DBL_NAN;
1367 ~~~
1368
1369 If your system supports `__float128` then you can also use this 128 bit
1370 floating point type with a custom serializer:
1371
1372 ~~~{.cpp}
1373 #import "custom/float128.h"
1374 ... // use xsd__decimal
1375 ~~~
1376
1377 Then use the `xsd__decimal` alias of `__float128`, which has a serializer. Do
1378 not use `__float128` directly, which is transient (not serializable).
1379
1380 To check for <i>`INF`</i>, <i>`-INF`</i>, and <i>`NaN`</i> of a `__float128`
1381 value use:
1382
1383 ~~~{.cpp}
1384 isinfq(x) && x > 0 // is x INF?
1385 isinfq(x) && x < 0 // is x -INF?
1386 isnanq(x) // is x NaN?
1387 ~~~
1388
1389 The range of a `typedef`-defined numerical type can be restricted using the range
1390 `:` operator with inclusive lower and upper bounds. For example:
1391
1392 ~~~{.cpp}
1393 typedef int ns__narrow -10 : 10;
1394 ~~~
1395
1396 This maps to a simpleType restriction of <i>`xsd:int`</i> in the soapcpp2-generated
1397 schema:
1398
1399 <div class="alt">
1400 ~~~{.xml}
1401 <simpleType name="narrow">
1402 <restriction base="xsd:int">
1403 <minInclusive value="-10"/>
1404 <maxInclusive value="10"/>
1405 </restriction>
1406 </simpleType>
1407 ~~~
1408 </div>
1409
1410 The lower and upper bound of a range are optional. When omitted, values are
1411 not bound from below or from above, respectively.
1412
1413 The range of a floating point `typedef`-defined type can be restricted within
1414 floating point constant bounds.
1415
1416 Also with a floating point `typedef` a `printf`-format pattern can be given of the
1417 form `"%[width][.precision]f"` to format decimal values using the given width
1418 and precision fields:
1419
1420 ~~~{.cpp}
1421 typedef float ns__PH "%5.2f" 0.0 : 14.0;
1422 ~~~
1423
1424 This maps to a simpleType restriction of <i>`xsd:float`</i> in the soapcpp2-generated
1425 schema:
1426
1427 <div class="alt">
1428 ~~~{.xml}
1429 <simpleType name="PH">
1430 <restriction base="xsd:float">
1431 <totalDigits value="5"/>
1432 <fractionDigits value="2"/>
1433 <minInclusive value="0"/>
1434 <maxInclusive value="14"/>
1435 </restriction>
1436 </simpleType>
1437 ~~~
1438 </div>
1439
1440 For exclusive bounds, we use the `<` operator instead of the `:` range
1441 operator:
1442
1443 ~~~{.cpp}
1444 typedef float ns__epsilon 0.0 < 1.0;
1445 ~~~
1446
1447 Values `eps` of `ns__epsilon` are restricted between `0.0 < eps < 1.0`.
1448
1449 This maps to a simpleType restriction of <i>`xsd:float`</i> in the soapcpp2-generated
1450 schema:
1451
1452 <div class="alt">
1453 ~~~{.xml}
1454 <simpleType name="epsilon">
1455 <restriction base="xsd:float">
1456 <minExclusive value="0"/>
1457 <maxExclusive value="1"/>
1458 </restriction>
1459 </simpleType>
1460 ~~~
1461 </div>
1462
1463 To make just one of the bounds exclusive, while keeping the other bound
1464 inclusive, we add a `<` on the left or on the right side of the range ':'
1465 operator. For example:
1466
1467 ~~~{.cpp}
1468 typedef float ns__pos 0.0 < : ; // 0.0 < pos
1469 typedef float ns__neg : < 0.0 ; // neg < 0.0
1470 ~~~
1471
1472 It is valid to make both left and right side exclusive with `< : <` which is in
1473 fact identical to the exlusive range `<` operator:
1474
1475 ~~~{.cpp}
1476 typedef float ns__epsilon 0.0 < : < 1.0; // 0.0 < eps < 1.0
1477 ~~~
1478
1479 It helps to think of the `:` as a placeholder of the value between the two
1480 bounds, which is easier to memorize than the shorthand forms of bounds from
1481 which the `:` is removed:
1482
1483 | bounds | validation check | shorthand |
1484 | ------------ | ---------------- | ----------- |
1485 | `1 : ` | 1 <= x | `1 ` |
1486 | `1 : 10 ` | 1 <= x <= 10 | |
1487 | ` : 10 ` | x <= 10 | |
1488 | `1 < : < 10` | 1 < x < 10 | `1 < 10 ` |
1489 | `1 : < 10` | 1 <= x < 10 | |
1490 | ` : < 10` | x < 10 | ` < 10 ` |
1491 | `1 < : ` | 1 < x | `1 < ` |
1492 | `1 < : 10 ` | 1 < x <= 10 | |
1493
1494 Besides `float`, also `double` and `long double` values can be restricted. For
1495 example, consider a nonzero probability extended floating point precision type:
1496
1497 ~~~{.cpp}
1498 #import "custom/long_double.h"
1499 typedef long double ns__probability "%16Lg" 0.0 < : 1.0;
1500 ~~~
1501
1502 Value range restrictions are validated by the parser for all inbound XML data.
1503 A type fault `SOAP_TYPE` will be thrown by the deserializer if the value is out
1504 of range.
1505
1506 Finally, if your system supports `__int128_t` then you can also use this 128
1507 bit integer type with a custom serializer:
1508
1509 ~~~{.cpp}
1510 #import "custom/int128.h"
1511 ... // use xsd__integer
1512 ~~~
1513
1514 Use the `xsd__integer` alias of `__int128_t`, which has a serializer. Do not
1515 use `__int128_t` directly, which is transient (not serializable).
1516
1517 To convert numeric values to a string, we use the auto-generated function for
1518 numeric type `T`:
1519
1520 ~~~{.cpp}
1521 const char *soap_T2s(struct soap*, T val)
1522 ~~~
1523
1524 For numeric types `T`, the string returned is stored in an internal buffer of
1525 the current `soap` context, so you should copy it to keep it from being
1526 overwritten. For example, use `char *soap_strdup(struct soap*, const char*)`.
1527
1528 To convert a string to a numeric value, we use the auto-generated function
1529
1530 ~~~{.cpp}
1531 int soap_s2T(struct soap*, const char *str, T *val)
1532 ~~~
1533
1534 where `T` is for example `int`, `LONG64`, `float`, `decimal` (the custom
1535 serializer name of `long double`) or `xsd__integer` (the custom serializer name
1536 of `__int128_t`). The function `soap_s2T` returns `SOAP_OK` on success or an
1537 error when the value is not numeric. For floating point types, `"INF"`, `"-INF"`
1538 and `"NaN"` are valid strings to convert to numbers.
1539
1540 🔝 [Back to table of contents](#)
1541
1542 String types {#toxsd6}
1543 ------------
1544
1545 String types are mapped to the built-in <i>`xsd:string`</i> and <i>`xsd:QName`</i> XSD types.
1546
1547 The wide strings `wchar_t*` and `std::wstring` may contain Unicode that is
1548 preserved in the XML value space.
1549
1550 Strings `char*` and `std::string` can only contain extended Latin, but we can
1551 store UTF-8 content that is preserved in the XML value space when the `soap`
1552 context is initialized with the flag `SOAP_C_UTFSTRING`.
1553
1554 @warning Beware that many XML 1.0 parsers reject all control characters (those
1555 between `#x1` and `#x1F`) except for `#x9`, `#xA`, and `#xD`. With the
1556 newer XML 1.1 version parsers (including gSOAP) you should be fine.
1557
1558 The length of a string of a `typedef`-defined string type can be restricted:
1559
1560 ~~~{.cpp}
1561 typedef std::string ns__password 6 : 16;
1562 ~~~
1563
1564 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1565 schema:
1566
1567 <div class="alt">
1568 ~~~{.xml}
1569 <simpleType name="password">
1570 <restriction base="xsd:string">
1571 <minLength value="6"/>
1572 <maxLength value="16"/>
1573 </restriction>
1574 </simpleType>
1575 ~~~
1576 </div>
1577
1578 String length restrictions are validated by the parser for inbound XML data.
1579 A value length fault `SOAP_LENGTH` will be thrown by the deserializer if the
1580 string is too long or too short.
1581
1582 In addition, an XSD regex pattern restriction can be associated with a string
1583 typedef:
1584
1585 ~~~{.cpp}
1586 typedef std::string ns__password "([a-zA-Z]|[0-9]|-)+" 6 : 16;
1587 ~~~
1588
1589 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1590 schema:
1591
1592 <div class="alt">
1593 ~~~{.xml}
1594 <simpleType name="password">
1595 <restriction base="xsd:string">
1596 <pattern value="([a-zA-Z0-9]|-)+"/>
1597 <minLength value="6"/>
1598 <maxLength value="16"/>
1599 </restriction>
1600 </simpleType>
1601 ~~~
1602 </div>
1603
1604 Pattern restrictions are validated by the parser for inbound XML data only if
1605 the `soap::fsvalidate` and `soap::fwvalidate` callbacks are defined.
1606
1607 Exclusive length bounds can be used with strings:
1608
1609 ~~~{.cpp}
1610 typedef std::string ns__string255 : < 256; // same as 0 : 255
1611 ~~~
1612
1613 Fixed-size strings (`char[N]`) are rare occurrences in the wild, but apparently
1614 still used in some projects to store strings. To facilitate fixed-size string
1615 serialization, use <b>`soapcpp2 -b`</b> option <b>`-b`</b>. For example:
1616
1617 ~~~{.cpp}
1618 typedef char ns__buffer[10]; // requires soapcpp2 option -b
1619 ~~~
1620
1621 which maps to a simpleType restriction of <i>`xsd:string`</i> in the soapcpp2-generated
1622 schema:
1623
1624 <div class="alt">
1625 ~~~{.xml}
1626 <simpleType name="buffer">
1627 <restriction base="xsd:string">
1628 <maxLength value="9"/>
1629 </restriction>
1630 </simpleType>
1631 ~~~
1632 </div>
1633
1634 Fixed-size strings must contain NUL-terminated text and should not contain raw
1635 binary data. Also, the length limitation is more restrictive for UTF-8 content
1636 (enabled with the `SOAP_C_UTFSTRING`) that requires multibyte character
1637 encodings. As a consequence, UTF-8 content may be truncated to fit.
1638
1639 Raw binary data can be stored in a `xsd__base64Binary` or `xsd__hexBinary`
1640 structure, or transmitted as a MIME attachment.
1641
1642 The built-in `_QName` type is a regular C string type (`char*`) that maps to
1643 <i>`xsd:QName`</i> but has the added advantage that it holds normalized qualified names.
1644 There are actually two forms of normalized QName content, to ensure any QName
1645 is represented accurately:
1646
1647 ~~~{.cpp}
1648 "prefix:name"
1649 "\"URI\":name"
1650 ~~~
1651
1652 The first form of string is used when the prefix (and the binding URI) is
1653 defined in the namespace table and is bound to a URI (see the .nsmap file).
1654 The second form is used when the URI is not defined in the namespace table and
1655 therefore no prefix is available to bind and normalize the URI to.
1656
1657 A `_QName` string may contain a sequence of space-separated QName values, not
1658 just one, and all QName values are normalized to the format shown above.
1659
1660 To define a `std::string` base type for <i>`xsd:QName`</i>, we use a `typedef`:
1661
1662 ~~~{.cpp}
1663 typedef std::string xsd__QName;
1664 ~~~
1665
1666 The `xsd__QName` string content is normalized, just as with the `_QName`
1667 normalization.
1668
1669 To serialize strings that contain literal XML content to be reproduced in the
1670 XML value space, use the built-in `_XML` string type, which is a regular C
1671 string type (`char*`) that maps to plain XML CDATA.
1672
1673 To define a `std::string` base type for literal XML content, use a `typedef`:
1674
1675 ~~~{.cpp}
1676 typedef std::string XML;
1677 ~~~
1678
1679 Strings can hold any of the values of the XSD built-in primitive types. We can
1680 use a string `typedef` to declare the use of the string type as a XSD built-in
1681 type:
1682
1683 ~~~{.cpp}
1684 typedef std::string xsd__token;
1685 ~~~
1686
1687 You must ensure that the string values we populate in this type conform to the
1688 XML standard, which in case of <i>`xsd:token`</i> is the lexical and value spaces of
1689 <i>`xsd:token`</i> are the sets of all strings after whitespace replacement of any
1690 occurrence of `#x9`, `#xA` , and `#xD` by `#x20` and collapsing.
1691
1692 As of version 2.8.49, the gSOAP parser will automatically collapse or replace
1693 the white space content when receiving data for XSD types that require white
1694 space collapsed or replaced. This normalization is applied to strings
1695 directly. The decision to collapse or replace is based on the `typedef` name
1696 corresponding to the built-in string-based XSD type.
1697
1698 To copy `char*` or `wchar_t*` strings with a context that manages the allocated
1699 memory, use functions
1700
1701 ~~~{.cpp}
1702 char *soap_strdup(struct soap*, const char*)
1703 wchar_t *soap_wstrdup(struct soap*, const wchar_t*)
1704 ~~~
1705
1706 To convert a wide string to a UTF-8 encoded string, use function
1707
1708 ~~~{.cpp}
1709 const char* SOAP_FMAC2 soap_wchar2s(struct soap*, const wchar_t *s)
1710 ~~~
1711
1712 The function allocates and returns a string, with its memory being managed by
1713 the context.
1714
1715 To convert a UTF-8 encoded string to a wide string, use function
1716
1717 ~~~{.cpp}
1718 int soap_s2wchar(struct soap*, const char *from, wchar_t **to, long minlen, long maxlen)
1719 ~~~
1720
1721 where `to` is set to point to an allocated `wchar_t*` string. Pass `-1` for
1722 `minlen` and `maxlen` to ignore length constraints on the target string. The
1723 function returns `SOAP_OK` or an error when the length constraints are not met.
1724
1725 🔝 [Back to table of contents](#)
1726
1727 Date and time types {#toxsd7}
1728 -------------------
1729
1730 The C/C++ `time_t` type is mapped to the built-in <i>`xsd:dateTime`</i> XSD type that
1731 represents a date and time within a time zone (typically UTC).
1732
1733 The XML value space contains ISO 8601 Gregorian time instances of the form
1734 <i>`[-]CCYY-MM-DDThh:mm:ss.sss[Z|(+|-)hh:mm]`</i>, where <i>`Z`</i> is the UTC time zone
1735 or a time zone offset <i>`(+|-)hh:mm]`</i> from UTC is used.
1736
1737 A `time_t` value is considered and represented in UTC by the serializer.
1738
1739 Because the `time_t` value range is restricted to dates after 01/01/1970 and
1740 before 2038 assuming `time_t` is a `long` 32 bit, care must be taken to ensure
1741 the range of <i>`xsd:dateTime`</i> values in XML exchanges do not exceed the `time_t`
1742 range.
1743
1744 This restriction does not hold for `struct tm` (<i>`time.h`</i> library), which we can use
1745 to store and exchange a date and time in UTC without date range restrictions.
1746 The serializer uses the `struct tm` members directly for the XML value space of
1747 <i>`xsd:dateTime`</i>:
1748
1749 ~~~{.cpp}
1750 struct tm
1751 {
1752 int tm_sec; // seconds (0 - 60)
1753 int tm_min; // minutes (0 - 59)
1754 int tm_hour; // hours (0 - 23)
1755 int tm_mday; // day of month (1 - 31)
1756 int tm_mon; // month of year (0 - 11)
1757 int tm_year; // year - 1900
1758 int tm_wday; // day of week (Sunday = 0) (NOT USED)
1759 int tm_yday; // day of year (0 - 365) (NOT USED)
1760 int tm_isdst; // is summer time in effect?
1761 char* tm_zone; // abbreviation of timezone (NOT USED)
1762 };
1763 ~~~
1764
1765 You will lose the day of the week information. It is always Sunday
1766 (`tm_wday=0`) and the day of the year is not set either. The time zone is UTC.
1767
1768 This `struct tm` type is mapped to the built-in <i>`xsd:dateTime`</i> XSD type and
1769 serialized with the custom serializer <i>`gsoap/custom/struct_tm.h`</i> that declares a
1770 `xsd__dateTime` type:
1771
1772 ~~~{.cpp}
1773 #import "custom/struct_tm.h" // import typedef struct tm xsd__dateTime;
1774 ... // use xsd__dateTime
1775 ~~~
1776
1777 Compile and link your code with <i>`gsoap/custom/struct_tm.c`</i>.
1778
1779 The `struct timeval` (<i>`sys/time.h`</i> library) type is mapped to the
1780 built-in <i>`xsd:dateTime`</i> XSD type and serialized with the custom serializer
1781 <i>`gsoap/custom/struct_timeval.h`</i> that declares a `xsd__dateTime` type:
1782
1783 ~~~{.cpp}
1784 #import "custom/struct_timeval.h" // import typedef struct timeval xsd__dateTime;
1785 ... // use xsd__dateTime
1786 ~~~
1787
1788 Compile and link your code with <i>`gsoap/custom/struct_timeval.c`</i>.
1789
1790 The same value range restrictions apply to `struct timeval` as they apply to
1791 `time_t`. The added benefit of `struct timeval` is the addition of a
1792 microsecond-precise clock:
1793
1794 ~~~{.cpp}
1795 struct timeval
1796 {
1797 time_t tv_sec; // seconds since Jan. 1, 1970
1798 suseconds_t tv_usec; // and microseconds
1799 };
1800 ~~~
1801
1802 A C++11 `std::chrono::system_clock::time_point` type is mapped to the built-in
1803 <i>`xsd:dateTime`</i> XSD type and serialized with the custom serializer
1804 <i>`gsoap/custom/chrono_time_point.h`</i> that declares a `xsd__dateTime` type:
1805
1806 ~~~{.cpp}
1807 #import "custom/chrono_time_point.h" // import typedef std::chrono::system_clock::time_point xsd__dateTime;
1808 ... // use xsd__dateTime
1809 ~~~
1810
1811 Compile and link your code with <i>`gsoap/custom/chrono_time_point.cpp`</i>.
1812
1813 The `struct tm` type is mapped to the built-in <i>`xsd:date`</i> XSD type and serialized
1814 with the custom serializer <i>`gsoap/custom/struct_tm_date.h`</i> that declares a
1815 `xsd__date` type:
1816
1817 ~~~{.cpp}
1818 #import "custom/struct_tm_date.h" // import typedef struct tm xsd__date;
1819 ... // use xsd__date
1820 ~~~
1821
1822 Compile and link your code with <i>`gsoap/custom/struct_tm_date.c`</i>.
1823
1824 The XML value space of <i>`xsd:date`</i> are Gregorian calendar dates of the form
1825 <i>`[-]CCYY-MM-DD[Z|(+|-)hh:mm]`</i> with a time zone.
1826
1827 The serializer ignores the time part and the deserializer only populates the
1828 date part of the struct, setting the time to 00:00:00. There is no unreasonable
1829 limit on the date range because the year field is stored as an integer (`int`).
1830
1831 An `unsigned long long` (`ULONG64` or `uint64_t`) type that contains a 24 hour
1832 time in microseconds UTC is mapped to the built-in <i>`xsd:time`</i> XSD type and
1833 serialized with the custom serializer <i>`gsoap/custom/long_time.h`</i> that declares a
1834 `xsd__time` type:
1835
1836 ~~~{.cpp}
1837 #import "custom/long_time.h" // import typedef unsigned long long xsd__time;
1838 ... // use xsd__time
1839 ~~~
1840
1841 Compile and link your code with <i>`gsoap/custom/long_time.c`</i>.
1842
1843 This type represents `00:00:00.000000` to `23:59:59.999999`, from 0 to an
1844 upper bound of 86,399,999,999. A microsecond resolution means that a 1 second
1845 increment requires an increment of 1,000,000 in the integer value.
1846
1847 The XML value space of <i>`xsd:time`</i> are points in time recurring each day of the
1848 form <i>`hh:mm:ss.sss[Z|(+|-)hh:mm]`</i>, where <i>`Z`</i> is the UTC time zone or a time
1849 zone offset from UTC is used. The `xsd__time` value is always considered and
1850 represented in UTC by the serializer.
1851
1852 To convert date and/or time values to a string, we use the auto-generated
1853 function for type `T`:
1854
1855 ~~~{.cpp}
1856 const char *soap_T2s(struct soap*, T val)
1857 ~~~
1858
1859 For date and time types `T`, the string returned is stored in an internal
1860 buffer of the current `soap` context, so you should copy it to keep it from being
1861 overwritten. For example, use `char *soap_strdup(struct soap*, const char*)`.
1862
1863 To convert a string to a date/time value, we use the auto-generated function
1864
1865 ~~~{.cpp}
1866 int soap_s2T(struct soap*, const char *str, T *val)
1867 ~~~
1868
1869 where `T` is for example `dateTime` (for `time_t`), `xsd__dateTime` (for
1870 `struct tm`, `struct timeval`, or `std::chrono::system_clock::time_point`).
1871 The function `soap_s2T` returns `SOAP_OK` on success or an error when the value
1872 is not a date/time.
1873
1874 🔝 [Back to table of contents](#)
1875
1876 Time duration types {#toxsd8}
1877 -------------------
1878
1879 The XML value space of <i>`xsd:duration`</i> are values of the form <i>`PnYnMnDTnHnMnS`</i>
1880 where the capital letters are delimiters. Delimiters may be omitted when the
1881 corresponding member is not used.
1882
1883 A `long long` (`LONG64` or `int64_t`) type that contains a duration (time
1884 lapse) in milliseconds is mapped to the built-in <i>`xsd:duration`</i> XSD type and
1885 serialized with the custom serializer <i>`gsoap/custom/duration.h`</i> that declares a
1886 `xsd__duration` type:
1887
1888 ~~~{.cpp}
1889 #import "custom/duration.h" // import typedef long long xsd__duration;
1890 ... // use xsd__duration
1891 ~~~
1892
1893 Compile and link your code with <i>`gsoap/custom/duration.c`</i>.
1894
1895 The duration type `xsd__duration` can represent 106,751,991,167 days forward
1896 and backward with millisecond precision.
1897
1898 Durations that exceed a month are always output in days, rather than months to
1899 avoid days-per-month conversion inacurracies.
1900
1901 Durations that are received in years and months instead of total number of days
1902 from a reference point are not well defined, since there is no accepted
1903 reference time point (it may or may not be the current time). The decoder
1904 simple assumes that there are 30 days per month. For example, conversion of
1905 "P4M" gives 120 days. Therefore, the durations "P4M" and "P120D" are assumed
1906 to be identical, which is not necessarily true depending on the reference point
1907 in time.
1908
1909 Rescaling of the duration value by may be needed when adding the duration value
1910 to a `time_t` value, because `time_t` may or may not have a seconds resolution,
1911 depending on the platform and possible changes to `time_t`.
1912
1913 Rescaling is done automatically when you add a C++11 `std::chrono::nanoseconds`
1914 value to a `std::chrono::system_clock::time_point` value. To use
1915 `std::chrono::nanoseconds` as <i>`xsd:duration`</i>:
1916
1917 ~~~{.cpp}
1918 #import "custom/chrono_duration.h" // import typedef std::chrono::duration xsd__duration;
1919 ... // use xsd__duration
1920 ~~~
1921
1922 Compile and link your code with <i>`gsoap/custom/chrono_duration.cpp`</i>.
1923
1924 This type can represent 384,307,168 days (2^63 nanoseconds) forwards and
1925 backwards in time in increments of 1 ns (1/1000000000 second).
1926
1927 The same observations with respect to receiving durations in years and months
1928 apply to this serializer's decoder.
1929
1930 To convert duration values to a string, we use the auto-generated function
1931
1932 ~~~{.cpp}
1933 const char *soap_xsd__duration2s(struct soap*, xsd__duration val)
1934 ~~~
1935
1936 The string returned is stored in an internal buffer, so you should copy it to
1937 keep it from being overwritten, Use `soap_strdup(struct soap*, const char*)`
1938 for example to copy this string.
1939
1940 To convert a string to a duration value, we use the auto-generated function
1941
1942 ~~~{.cpp}
1943 int soap_s2xsd__dateTime(struct soap*, const char *str, xsd__dateTime *val)
1944 ~~~
1945
1946 The function returns `SOAP_OK` on success or an error when the value is not a
1947 duration.
1948
1949 🔝 [Back to table of contents](#)
1950
1951 Classes and structs {#toxsd9}
1952 -------------------
1953
1954 Classes and structs are mapped to XSD complexTypes. The XML value space
1955 consists of XML elements with attributes and subelements, possibly constrained
1956 by XML schema validation rules that enforce element and attribute occurrence
1957 contraints, numerical value range constraints, and string length and pattern
1958 constraints.
1959
1960 Classes that are declared with the gSOAP tools are limited to single
1961 inheritence only. The soapcpp2 tool does not allow structs to be inherited.
1962
1963 The class and struct name is bound to an XML namespace by means of the prefix
1964 naming convention or by using [colon notation](#toxsd1):
1965
1966 ~~~{.cpp}
1967 //gsoap ns schema namespace: urn:types
1968 class ns__record
1969 {
1970 public:
1971 std::string name;
1972 uint64_t SSN;
1973 ns__record *spouse;
1974 ns__record();
1975 ~ns__record();
1976 protected:
1977 struct soap *soap;
1978 };
1979 ~~~
1980
1981 In the example above, we also added a context pointer to the `soap` context that
1982 manages this instance. It is set when the instance is created in the engine's
1983 context, for example when deserialized and populated by the engine.
1984
1985 The class maps to a complexType in the soapcpp2-generated XML schema:
1986
1987 <div class="alt">
1988 ~~~{.xml}
1989 <complexType name="record">
1990 <sequence>
1991 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
1992 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
1993 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" nillable="true"/>
1994 </sequence>
1995 </complexType>
1996 ~~~
1997 </div>
1998
1999 The following sections apply to both structs and classes. Structs require the
2000 use of the `struct` keyword with the struct name, otherwise soapcpp2 will throw
2001 a syntax error. As is often done in C, use a `typedef` to declare a `struct`
2002 that can be used without the `struct` keyword.
2003
2004 🔝 [Back to table of contents](#)
2005
2006 ### Serializable versus transient types and data members {#toxsd9-1}
2007
2008 Public data members of a class or struct are serializable when their types are
2009 serializable. Private and protected members are transient and not
2010 serializable.
2011
2012 Also `const` and `static` members are not serializable, with the exception of
2013 `const char*` and `const wchar_t*`. Types and specific class/struct members
2014 can be made transient with the `extern` qualifier for types and by marking
2015 members with `[` and `]`:
2016
2017 ~~~{.cpp}
2018 extern class std::ostream; // declare std::ostream transient
2019 class ns__record
2020 {
2021 public:
2022 [ int num; ] // not serialized: member is marked transient with [ ]
2023 std::ostream out; // not serialized: std:ostream is transient
2024 static const int MAX = 1024; // not serialized: static const member
2025 private:
2026 std::string id; // not serialized: private member
2027 };
2028 ~~~
2029
2030 By declaring `std::ostream` transient with `extern` you can use this type
2031 wherever you need it without soapcpp2 complaining that this class and any other
2032 class or type declared as `extern` is not defined. Do not use `extern` with
2033 `typedef`, because this declares a custom serializer, see
2034 [adding custom serializers](#custom).
2035
2036 Marking members transient with `[` and `]` makes them transient (and visually
2037 makes them stand out). This has otherwise no effect on the generated code for
2038 the class or struct to be used in your application code.
2039
2040 🔝 [Back to table of contents](#)
2041
2042 ### Derived types in C++ {#toxsd9-1-1}
2043
2044 Extensible and restricted types in XML schemas are derived types from single
2045 simple and complex base types. XML schema derived types are naturally
2046 represented by C++ derived classes using single inheritance. Besides the
2047 concept of extensions versus restrictions, there are two kinds of derived
2048 types: complexTypes with simpleContent, meaning types with XML CDATA values,
2049 and complexTypes with complexContent, meaning types with sub-elements. Both
2050 are permitted to have one or more XML attributes.
2051
2052 A complexType with simpleContent is defined as a wrapper to contain XML CDATA
2053 values and any number of attributes, see
2054 [wrapper class/struct with simpleContent](#toxsd10-4).
2055 Wrapper class/struct types can form a hierarchy of derived types in C++ using
2056 inheritance. For example:
2057
2058 ~~~{.cpp}
2059 class xsd__anyType
2060 {
2061 public:
2062 std::string __item; // string to hold any simpleContent
2063 };
2064 class ns__data : public xsd__anyType
2065 {
2066 public:
2067 @ std::string value 1; // extends xsd:anyType with a required attribute
2068 };
2069 ~~~
2070
2071 The `ns__data` class maps to a complexType in the soapcpp2-generated XML schema:
2072
2073 <div class="alt">
2074 ~~~{.xml}
2075 <complexType name="string">
2076 <simpleContent>
2077 <extension base="xsd:string">
2078 <attribute name="value" type="xsd:string" use="required"/>
2079 </extension>
2080 </simpleContent>
2081 </complexType>
2082 ~~~
2083 </div>
2084
2085 The XML value space consists of an element with the string contents an optional
2086 attribute:
2087
2088 <div class="alt">
2089 ~~~{.xml}
2090 <ns:data value="abc">xyz</ns:data>
2091 ~~~
2092 </div>
2093
2094 By contrast, a complexType with complexContent typically extends a given base
2095 complexType. For example:
2096
2097 ~~~{.cpp}
2098 class ns__base
2099 {
2100 public:
2101 std::string name 1;
2102 int number 1;
2103 };
2104 class ns__derived : public ns__base
2105 {
2106 public:
2107 @ std::string value 1; // extends ns:base with an attribute
2108 std::string text 1; // extends ns:base with an element
2109 };
2110 ~~~
2111
2112 The `ns__base` and `ns__derived` classes maps to complexTypes in the soapcpp2-generated XML schema:
2113
2114 <div class="alt">
2115 ~~~{.xml}
2116 <complexType name="base">
2117 <sequence>
2118 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
2119 <element name="number" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2120 </sequence>
2121 </complexType>
2122 <complexType name="derived">
2123 <complexContent>
2124 <extension base="ns:base">
2125 <sequence>
2126 <element name="text" type="xsd:string" minOccurs="1" maxOccurs="1"/>
2127 </sequence>
2128 </extension>
2129 </complexContent>
2130 <attribute name="value" type="xsd:string" use="required"/>
2131 </complexType>
2132 ~~~
2133 </div>
2134
2135 The XML value space of `ns__derived` consists of three requires child elements
2136 and an optional attribute:
2137
2138 <div class="alt">
2139 ~~~{.xml}
2140 <ns:derived value="abc">
2141 <name>def</name>
2142 <number>123</number>
2143 <text>xyz</text>
2144 </ns:derived>
2145 ~~~
2146 </div>
2147
2148 Derived types can be used for two main purposes in XML schema by extending or
2149 restricting base types. One purpose is to reuse a base type when defining a
2150 derived type, such that common parts do not need to be replicated. The second
2151 purpose is to be able to use a derived type in place of a base type in XML, which
2152 is indicated by an <i>`xsi:type`</i> attribute with the qualified name of the
2153 derived type. Consider for example the following class that uses the
2154 previously declared base types `xsd__anyType` and `ns__base`:
2155
2156 ~~~{.cpp}
2157 class ns__record
2158 {
2159 public:
2160 xsd__anyType *base1 1; // required element
2161 ns__base *base2 1; // required element
2162 };
2163 ~~~
2164
2165 We can assign base type values to the `ns_record` members:
2166
2167 ~~~{.cpp}
2168 ns__record record;
2169 record.base1 = soap_new_xsd__anyType(soap);
2170 record.base2 = soap_new_ns__base(soap);
2171 soap_write_ns__record(soap, &record);
2172 ~~~
2173
2174 This produces the following XML fragment populated with default values (empty
2175 text for strings and zeros for numbers), where element <i>`base1`</i> has a
2176 simpleContent value and element <i>`base2`</i> has two child elements:
2177
2178 <div class="alt">
2179 ~~~{.xml}
2180 <ns:record>
2181 <base1></base1>
2182 <base2>
2183 <name></name>
2184 <number>0</number>
2185 </base2>
2186 </ns:record>
2187 ~~~
2188 </div>
2189
2190 We can also assign derived type values to the `ns_record` members:
2191
2192 ~~~{.cpp}
2193 ns__record record;
2194 record.base1 = soap_new_ns__data(soap);
2195 record.base2 = soap_new_ns__derived(soap);
2196 soap_write_ns__record(soap, &record);
2197 ~~~
2198
2199 This produces the following XML fragment populated with default values (empty
2200 text for strings and zeros for numbers), where element <i>`base1`</i> has
2201 schema type <i>`ns:data`</i> with simpleContent and an attribute, and
2202 <i>`base2`</i> has schema type <i>`ns:derived`</i> with three child elements
2203 and an attribute:
2204
2205 <div class="alt">
2206 ~~~{.xml}
2207 <ns:record>
2208 <base1 xsi:type="ns:data" value=""></base1>
2209 <base2 xsi:type="ns:derived" value="">
2210 <name></name>
2211 <number>0</number>
2212 <text></text>
2213 </base2>
2214 </ns:record>
2215 ~~~
2216 </div>
2217
2218 Deserialization automatically allocates and assigns a `ns__base` class instance to a
2219 `ns__base` pointer when deserializing the <i>`ns:base`</i> schema type and allocates and
2220 assigns a `ns__derived` class instance to a `ns__base` pointer when deserializing the
2221 <i>`ns:derived`</i> type when an element with <i>`xsi:type="ns:derived"`</i> is
2222 parsed. All classes are extended by soapcpp2 by a `soap_type()` method that
2223 returns the unique `SOAP_TYPE_T` value of the class `T`. This makes it easy to
2224 check whether the deserialized data contains a derived type to implement
2225 type-safe code, for example:
2226
2227 ~~~{.cpp}
2228 ns__record record;
2229 soap_read_ns__record(soap, &record);
2230 if (record.base1->soap_type() == SOAP_TYPE_ns__data)
2231 std::cout << "Derived ns:data "
2232 << dynamic_cast<ns__data*>(record.base1)->value
2233 << std::endl;
2234 else
2235 std::cout << "Base xsd:anyType" << std::endl;
2236 if (record.base2->soap_type() == SOAP_TYPE_ns__derived)
2237 std::cout << "Derived ns:derived "
2238 << dynamic_cast<ns__derived*>(record.base2)->value
2239 << std::endl;
2240 else
2241 std::cout << "Base ns:base" << std::endl;
2242 ~~~
2243
2244 This example should use the `SOAP_XML_STRICT` mode flag to initialize the
2245 `soap` context to ensure that all required values are present in the
2246 deserialized structures.
2247
2248 🔝 [Back to table of contents](#)
2249
2250 ### Derived types in C {#toxsd9-1-2}
2251
2252 While single inheritance works well in C++ to represent derived types as we
2253 discussed in the previous section, this will obviously not work in C. Two
2254 methods to serialize derived types in C are presented here. The first method
2255 uses `void*` to serialize anything. The second method is more accurate and is
2256 relatively new in gSOAP.
2257
2258 To serialize any type is possible with [tagged void pointer members](#toxsd9-12) to
2259 serialize data pointed to by a `void*` member, which can be any serializable
2260 type, such as derived types. For `void*` deserialization to work the XML
2261 parsed must contain an <i>`xsi:type`</i> attribute with a schema type. Only
2262 then can the deserializer instantiate the corresponding serializable C/C++
2263 type. Base types serialized do not require an <i>`xsi:type`</i> to indicate
2264 the base schema type, so this approach is not guaranteed to work and requires a
2265 workaround with an anonymous wrapper struct/class that contains both the base
2266 type and a `void*`. For example:
2267
2268 ~~~{.cpp}
2269 struct ns__base // a base type
2270 {
2271 char *name 1;
2272 int number 1;
2273 };
2274 struct ns__derived // extends ns__base with two additional members
2275 {
2276 char *name 1;
2277 int number 1;
2278 char *text 1;
2279 @ char *value 1;
2280 };
2281 struct __ns__base // a wrapper, not visible in XML
2282 {
2283 int __type; // the SOAP_TYPE_T pointed to by __self
2284 void *__self; // points to any type
2285 struct ns__base *__self; // wraps ns__base for the current element tag
2286 }
2287 class ns__record
2288 {
2289 struct __ns__base base;
2290 };
2291 ~~~
2292
2293 The `__ns__base` wrapper wraps the `ns__base` type to (de)serialize the
2294 <i>`base`</i> element that has no <i>`xsi:type`</i> attribute and uses `void*`
2295 to (de)serialize the <i>`base`</i> element that has <i>`xsi:type`</i>
2296 attribute. This works fine at the XML parsing level, but the generated
2297 XML schema components do not accurately represent the derived type, because it
2298 lacks the extension/restriction of the derived type (and the `__ns__base`
2299 wrapper is invisible).
2300
2301 Using `void*` to represent derived types in a base type wrapper is not very
2302 accurate because we can serialize anything, not just derived types of a given
2303 base type. The wrapper may also hold two values: the base type value and a
2304 derived type value. Furthermore, using arrays or containers that hold base and
2305 derived types becomes quite tricky because an array item could hold both the
2306 base and derived type.
2307
2308 As of gSOAP version 2.8.75, `wsdl2h -F` option `-F` generates base type structs
2309 extended with transient pointer members to its derived types. To serialize the
2310 base type itself, all of the pointer members are NULL. If one of the pointer
2311 members points to a derived type the derived type is serialized instead.
2312 Deserialization is automatic, in that the base type is deserialized if the
2313 element has no <i>`xsi:type`</i> attribute or the attribute is the base schema
2314 type, and a derived type is deserialized if the element has an
2315 <i>`xsi>type`</i> attribute with the derived schema type.
2316
2317 This method is fully automated for the wsdl2h tool to generate an interface
2318 header file for soapcpp2 with the type derivations in C. To use this method to
2319 generate code from WSDLs and XSDs, use `wsdl2h -F` option `-F`. This also
2320 works in C++ if desired, but C++ inheritance works fine without this method.
2321
2322 Using this method with soapcpp2 alone using a manually-specified interface
2323 header file produces the specified type inheritance in the soapcpp2-generated
2324 WSDL and XML schema files as complexType extensions.
2325
2326 The soapcpp2 tool warns if a derived type has multiple base types. At most one
2327 base type for a derived type may be specified.
2328
2329 This method with transient pointers to derived types makes it easy to use base
2330 and derived types in C:
2331
2332 ~~~{.cpp}
2333 struct ns__base // a base type
2334 {
2335 char *name 1;
2336 int number 1;
2337 [ struct ns__derived *ns__derived; ] // points to derived type if non-NULL
2338 };
2339 struct ns__derived // extends ns__base with two additional members
2340 {
2341 char *name 1;
2342 int number 1;
2343 char *text 1;
2344 @ char *value 1;
2345 };
2346 struct ns__record
2347 {
2348 struct ns__base base; // contains base type or derived type value
2349 };
2350 ~~~
2351
2352 The `ns__base` struct includes the special member `ns__derived` that points to
2353 a `ns__derived` value. This special member must be:
2354
2355 - a transient member (i.e. non-serializable) by placing the declaration within
2356 `[` and `]`, and
2357 - the member name must match the type name (to be more precise, at least the
2358 initial part of the member name must match the type name as in the example
2359 `ns__derived_` works too).
2360
2361 To serialize the `ns__base` value requires the `ns__derived` member to be NULL.
2362 To serialize the `ns__derived` value requires the `ns__derived` member to point
2363 to the `ns__derived` value to serialize and the `ns__base` members are
2364 irrelevant.
2365
2366 We can assign the base type value to the `ns_record::base` member:
2367
2368 ~~~{.cpp}
2369 struct ns__record record;
2370 soap_default_ns__record(soap, &record);
2371 soap_write_ns__record(soap, &record);
2372 ~~~
2373
2374 This produces the following XML fragment populated with default values (empty
2375 text for strings and zeros for numbers), where element <i>`base`</i> has two
2376 child elements:
2377
2378 <div class="alt">
2379 ~~~{.xml}
2380 <ns:record>
2381 <base>
2382 <name></name>
2383 <number>0</number>
2384 </base>
2385 </ns:record>
2386 ~~~
2387 </div>
2388
2389 We can also assign the derived type value to the `ns_record::base` member:
2390
2391 ~~~{.cpp}
2392 struct ns__record record;
2393 soap_default_ns__record(soap, &record);
2394 record.base.ns__derived = soap_new_ns__derived(soap, -1);
2395 soap_write_ns__record(soap, &record);
2396 ~~~
2397
2398 This produces the following XML fragment populated with default values (empty
2399 text for strings and zeros for numbers), where element <i>`base`</i> has schema
2400 type <i>`ns:derived`</i> with three child elements and an attribute:
2401
2402 <div class="alt">
2403 ~~~{.xml}
2404 <ns:record>
2405 <base xsi:type="ns:derived" value="">
2406 <name></name>
2407 <number>0</number>
2408 <text></text>
2409 </base>
2410 </ns:record>
2411 ~~~
2412 </div>
2413
2414 Deserialization automatically assigns values to the base members for the
2415 `ns__base` type and populates the `ns__derived` member when a derived type with
2416 <i>`xsi:type="ns:derived"`</i> is parsed. This makes it easy to decompose the
2417 deserialized data:
2418
2419 ~~~{.cpp}
2420 struct ns__record record;
2421 soap_read_ns__record(soap, &record);
2422 if (record.ns__derived)
2423 printf("Derived type with name=%s number=%d text=%s value=%s\n",
2424 record.ns__derived->name,
2425 record.ns__derived->number,
2426 record.ns__derived->text,
2427 record.ns__derived->value);
2428 else
2429 printf("Base type with name=%s number=%d\n",
2430 record.name,
2431 record.number);
2432 ~~~
2433
2434 This example requires the `SOAP_XML_STRICT` mode flag to initialize the `soap`
2435 context to ensure that all required values are present in the deserialized
2436 structures, otherwise the `char*` strings may be NULL since XML validation
2437 constraints are not enforced on the XML input.
2438
2439 Deeper levels of simulated inheritance are possible, for example:
2440
2441 ~~~{.cpp}
2442 struct ns__base // a base type
2443 {
2444 char *name 1;
2445 int number 1;
2446 [ struct ns__derived *ns__derived; ] // points to derived type if non-NULL
2447 };
2448 struct ns__derived // extends ns__base with two additional members
2449 {
2450 char *name 1;
2451 int number 1;
2452 char *text 1;
2453 @ char *value 1;
2454 [ struct ns__derived_derived *ns__derived_derived; ] // points to derived_derived type if non-NULL
2455 };
2456 struct ns__derived_derived // extends ns__derived with an additional member
2457 {
2458 char *name 1;
2459 int number 1;
2460 char *text 1;
2461 @ char *value 1;
2462 @ char *type 1;
2463 };
2464 ~~~
2465
2466 This requires two pointer traversals from the base type `ns__base` via
2467 `ns__derived` to reach `ns__derived_derived`.
2468
2469 🔝 [Back to table of contents](#)
2470
2471 ### Volatile classes and structs {#toxsd9-2}
2472
2473 Classes and structs can be declared `volatile` in the interface header file for
2474 soapcpp2, which only has meaning for the gSOAP tools. This annotation means
2475 that these types are already declared elsewhere in your project's source code
2476 and you do not want soapcpp2 to generate code with a second declaration of
2477 these types.
2478
2479 For example, `struct tm` is declared in the <i>`time.h`</i> library. You can
2480 make it serializable and include a partial list of data members that you want
2481 to serialize:
2482
2483 ~~~{.cpp}
2484 volatile struct tm
2485 {
2486 int tm_sec; // seconds (0 - 60)
2487 int tm_min; // minutes (0 - 59)
2488 int tm_hour; // hours (0 - 23)
2489 int tm_mday; // day of month (1 - 31)
2490 int tm_mon; // month of year (0 - 11)
2491 int tm_year; // year - 1900
2492 };
2493 ~~~
2494
2495 You can declare classes and structs `volatile` for any such types you want to
2496 serialize by only providing the public data members you want to serialize.
2497
2498 In addition, [colon notation](#toxsd2) is a simple and effective way to bind an
2499 existing class or struct to a schema. For example, you can change the `tm` name
2500 as follows without affecting the code that uses `struct tm` generated by
2501 soapcpp2:
2502
2503 ~~~{.cpp}
2504 volatile struct ns:tm { ... }
2505 ~~~
2506
2507 This struct maps to a complexType in the soapcpp2-generated XML schema:
2508
2509 <div class="alt">
2510 ~~~{.xml}
2511 <complexType name="tm">
2512 <sequence>
2513 <element name="tm-sec" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2514 <element name="tm-min" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2515 <element name="tm-hour" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2516 <element name="tm-mday" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2517 <element name="tm-mon" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2518 <element name="tm-year" type="xsd:int" minOccurs="1" maxOccurs="1"/>
2519 </sequence>
2520 </complexType>
2521 ~~~
2522 </div>
2523
2524 🔝 [Back to table of contents](#)
2525
2526 ### Mutable classes and structs {#toxsd9-3}
2527
2528 Classes and structs can be declared `mutable` with the gSOAP tools. This means
2529 that their definition can be spread out over the source code. This promotes the
2530 concept of a class or struct as a *row of named values*, also known as a *named
2531 tuple*, that can be extended at compile time in your source code with additional
2532 members. Because these types differ from the traditional object-oriented
2533 principles and design concepts of classes and objects, constructors and
2534 destructors cannot be defined (also because we cannot guarantee merging these
2535 into one such that all members will be initialized). A default constructor,
2536 copy constructor, assignment operation, and destructor will be assigned
2537 automatically by soapcpp2.
2538
2539 ~~~{.cpp}
2540 mutable struct ns__tuple
2541 {
2542 @ std::string id;
2543 };
2544
2545 mutable struct ns__tuple
2546 {
2547 std::string name;
2548 std::string value;
2549 };
2550 ~~~
2551
2552 The members are collected into one definition generated by soapcpp2. Members
2553 may be repeated from one definition to another, but only if their associated
2554 types are identical. So, for example, a third extension with a `value` member
2555 with a different type fails:
2556
2557 ~~~{.cpp}
2558 mutable struct ns__tuple
2559 {
2560 float value; // BAD: value is already declared std::string
2561 };
2562 ~~~
2563
2564 The `mutable` concept has proven to be very useful when declaring and
2565 collecting SOAP Headers for multiple services, which are collected into one
2566 `struct SOAP_ENV__Header` by the soapcpp2 tool.
2567
2568 🔝 [Back to table of contents](#)
2569
2570 ### Default and fixed member values {#toxsd9-4}
2571
2572 Class and struct data members in C and C++ may be declared with an optional
2573 default initialization value that is provided "inline" with the declaration of
2574 the member:
2575
2576 ~~~{.cpp}
2577 class ns__record
2578 {
2579 public:
2580 std::string name = "Joe";
2581 ...
2582 };
2583 ~~~
2584
2585 Alternatively, use C++11 default initialization syntax:
2586
2587 ~~~{.cpp}
2588 class ns__record
2589 {
2590 public:
2591 std::string name { "Joe" };
2592 ...
2593 };
2594 ~~~
2595
2596 These initializations are made by the default constructor that is added by
2597 soapcpp2 to each class and struct (in C++ only). A constructor is only added
2598 when a default constructor is not already defined with the class declaration.
2599
2600 You can explicitly (re)initialize an object with these initial values by using
2601 the soapcpp2 auto-generated functions:
2602
2603 - `void T::soap_default(struct soap*)` for `class T` (C++ only)
2604
2605 - `void soap_default_T(struct soap*, T*)` for `struct T` (C and C++).
2606
2607 If `T` is a struct or class that has a `soap` pointer member to a `::soap`
2608 context then this pointer member will be set to the first argument passed to
2609 these functions to initialize their `soap` pointer member.
2610
2611 Default value initializations can be provided for members that have primitive
2612 types (`bool`, `enum`, `time_t`, numeric and string types).
2613
2614 Default value initializations of pointer members is permitted, but the effect
2615 is different. To conform to XML schema validation, an attribute member that is
2616 a pointer to a primitive type will be assigned the default value when parsed
2617 from XML. An element member that is a pointer to a primitive type will be
2618 assigned when the element is empty when parsed from XML.
2619
2620 As of gSOAP 2.8.48 and greater, a fixed value can be assigned with a `==`. A
2621 fixed value is also verified by the parser's validator.
2622
2623 Default and fixed values for members with or without pointers are best
2624 explained with the following two example fragments.
2625
2626 A record class with default values for `std::string` (or `std::wstring`)
2627 attributes and elements is declared as follows:
2628
2629 ~~~{.cpp}
2630 class ns__record_with_default
2631 {
2632 public:
2633 @ std::string a = "A"; // optional XML attribute with default value "A"
2634 @ std::string b 1 = "B"; // required XML attribute with default value "B"
2635 @ std::string *c = "C"; // optional XML attribute with default value "C"
2636 std::string d 0 = "D"; // optional XML element with default value "D"
2637 std::string e = "E"; // required XML element with default value "E"
2638 std::string *f = "F"; // optional XML element with default value "F"
2639 ...
2640 };
2641 ~~~
2642
2643 Also `std::unique_ptr` and `std::shared_ptr` may be used instead of a regular
2644 pointer to strings.
2645
2646 With C `char*` (or `const char*`, `const wchar_t*`) strings in a struct, this
2647 becomes:
2648
2649 ~~~{.cpp}
2650 struct ns__record_with_default
2651 {
2652 @ char* a = "A"; // optional XML attribute with default value "A"
2653 @ char* b 1 = "B"; // required XML attribute with default value "B"
2654 char* e 1 = "E"; // required XML element with default value "E"
2655 char* f = "F"; // optional XML element with default value "F"
2656 ...
2657 };
2658 ~~~
2659
2660 By contrast to `std::string e`, `char* e` must be marked `1` to make it
2661 required, because pointer members are optional by default.
2662
2663 Attributes are considered optional by default, unless marked as required with
2664 the occurrence constraint `1`. Elements are considered required unless the
2665 member type is a pointer or if the member is marked optional with occurrence
2666 constraint `0`.
2667
2668 Instead of default values, fixed values indicate that the attribute or element
2669 must contain that value, and only that value, when provided in XML. A fixed
2670 value is specified with a `==`.
2671
2672 Attributes with default or fixed values may be omitted in XML. When absent,
2673 the default/fixed value is used at the receiving side, i.e. the deserializer
2674 assigns the default/fixed value when the attribute is absent. Therefore, there
2675 is no need to make attributes with default/fixed values pointer based, because
2676 there is no way to distinguish an omitted attribute from a populated attribute
2677 on the receiving side. The `c` member in the example above can be a
2678 non-pointer for this reason. The wsdl2h tool does not generate pointers for
2679 attributes with default/fixed values.
2680
2681 Elements with default or fixed values may be optional and the use of
2682 default/fixed values with elements differs from attributes. The default/fixed
2683 value of an element is only used for elements that are empty in the XML payload
2684 received. Omitted optional elements in the XML payload received are simply
2685 absent; no default/fixed value is assigned.
2686
2687 @note gSOAP 2.8.106 and greater treat `char*` and `wchar_t*` with explicit
2688 default and fixed values differently than previous versions. Versions prior to
2689 2.8.106 assign the default value when the corresponding XML element is absent,
2690 whereas 2.8.106 and greater assign NULL when the XML element is absent, exactly
2691 as documented in this updated version of this document. To revert to the old
2692 behavior, use <b>`soapcpp2 -z4`</b> option <b>`-z4`</b>. The change affects
2693 members `char* f` and `char* l` (see below).
2694
2695 A record class (can be a struct in C) with fixed values for attributes and
2696 elements is declared as follows:
2697
2698 ~~~{.cpp}
2699 class ns__record_with_fixed
2700 {
2701 public:
2702 @ std::string g == "G"; // optional XML attribute with fixed value "G"
2703 @ std::string h 1 == "H"; // required XML attribute with fixed value "H"
2704 @ std::string *i == "I"; // optional XML attribute with fixed value "I"
2705 std::string j 0 == "J"; // optional XML element with fixed value "J"
2706 std::string k == "K"; // required XML element with fixed value "K"
2707 std::string *l == "L"; // optional XML element with fixed value "L"
2708 ...
2709 };
2710 ~~~
2711
2712 With C `char*` (or `const char*`, `const wchar_t*`) strings in a struct, this
2713 becomes:
2714
2715 ~~~{.cpp}
2716 struct ns__record_with_fixed
2717 {
2718 @ char* g == "G"; // optional XML attribute with fixed value "G"
2719 @ char* h 1 == "H"; // required XML attribute with fixed value "H"
2720 char* k 1 == "K"; // required XML element with fixed value "K"
2721 char* l == "L"; // optional XML element with fixed value "L"
2722 ...
2723 };
2724 ~~~
2725
2726 The XML schema validation rules for the examples above are as follows:
2727
2728 Member | Notes
2729 ------ | ---------------------------------------------------------------------
2730 `a` | attribute may appear once; if it does not appear its value is "A", otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns the default value "A")
2731 `b` | has no effect when parsing XML (but note: instantiating `ns__record_with_default` assigns the default value "B")
2732 `c` | attribute may appear once; if it does not appear its value is "C", otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns NULL)
2733 `d` | element may appear once; if it does not appear or if it is empty, its value is "D"; otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns the default value "D")
2734 `e` | has no effect when parsing XML (but note: instantiating `ns__record_with_default` assigns the default value "E")
2735 `f` | element may appear once; if it does not appear it is not provided; if it does appear and it is empty, its value is "F"; otherwise its value is that given (also note: instantiating `ns__record_with_default` assigns NULL)
2736 `g` | attribute may appear once; if it does not appear its value is "G", if it does not appear its value is "G" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "G")
2737 `h` | attribute must appear once, its value must be "H" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "H")
2738 `i` | attribute may appear once; if it does not appear its value is "I", if it does not appear its value is "I" (also note: instantiating `ns__record_with_fixed` assigns NULL)
2739 `j` | element may appear once, if it does not appear it is not provided; if it does appear and it is empty, its value is "J"; if it does appear and it is not empty, its value must be "J" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "J")
2740 `k` | element must appear once, its value must be "K" (also note: instantiating `ns__record_with_fixed` assigns the fixed value "K")
2741 `l` | element may appear once, if it does not appear it is not provided; if it does appear and it is empty, its value is "J"; if it does appear and it is not empty, its value must be "J" (also note: instantiating `ns__record_with_fixed` assigns NULL)
2742
2743 Members of type `char[N]` (fixed length string) can have default and fixed
2744 values, when <b>`soapcpp2 -b`</b> option <b>`-b`</b> is used. Also `char**`
2745 (pointer to a string) members can have default and fixed values. However,
2746 members of this type will be initialized to NULL. The default/fixed values
2747 will be assigned with the same rules as for `char*` when deserialized from XML.
2748
2749 @see Section [operations on classes and structs](#toxsd9-14).
2750
2751 🔝 [Back to table of contents](#)
2752
2753 ### Attribute members {#toxsd9-5}
2754
2755 Class and struct data members are declared as XML attributes by annotating
2756 their type with a `@` qualifier:
2757
2758 ~~~{.cpp}
2759 class ns__record
2760 {
2761 public:
2762 @ std::string name; // required (non-pointer means required)
2763 @ uint64_t SSN; // required (non-pointer means required)
2764 ns__record *spouse; // optional (pointer means minOccurs=0)
2765 };
2766 ~~~
2767
2768 This class maps to a complexType in the soapcpp2-generated XML schema:
2769
2770 <div class="alt">
2771 ~~~{.xml}
2772 <complexType name="record">
2773 <sequence>
2774 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" nillable="true"/>
2775 </sequence>
2776 <attribute name="name" type="xsd:string" use="required"/>
2777 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2778 </complexType>
2779 ~~~
2780 </div>
2781
2782 An example XML instance of `ns__record` is:
2783
2784 <div class="alt">
2785 ~~~{.xml}
2786 <ns:record xmlns:ns="urn:types" name="Joe" SSN="1234567890">
2787 <spouse name="Jane" SSN="1987654320">
2788 </spouse>
2789 </ns:record>
2790 ~~~
2791 </div>
2792
2793 Attribute data members are restricted to primitive types (`bool`, `enum`,
2794 `time_t`, numeric and string types), `xsd__hexBinary`, `xsd__base64Binary`, and
2795 custom serializers, such as `xsd__dateTime`. Custom serializers for types that
2796 may be used as attributes should define `soap_s2T` and `soap_T2s` functions that
2797 convert values of type `T` to strings and back.
2798
2799 Attribute data members can be pointers and smart pointers to these types, which
2800 permits attributes to be optional.
2801
2802 🔝 [Back to table of contents](#)
2803
2804 ### Backtick XML tags {#toxsd9-5-1}
2805
2806 The XML tag name of a class/struct member is the name of the member with the
2807 usual XML tag translation, see [colon notation](#toxsd2).
2808
2809 To override the standard translation of identifier names to XML tag names of
2810 attributes and elements, add the XML tag name in backticks (requires gSOAP
2811 2.8.30 or greater):
2812
2813 ~~~{.cpp}
2814 class ns__record
2815 {
2816 public:
2817 @ std::string name `full-name`;
2818 @ uint64_t SSN `tax-id`;
2819 ns__record *spouse `married-to`;
2820 };
2821 ~~~
2822
2823 This class maps to a complexType in the soapcpp2-generated XML schema:
2824
2825 <div class="alt">
2826 ~~~{.xml}
2827 <complexType name="record">
2828 <sequence>
2829 <element name="married-to" type="ns:record" minOccurs="0" maxOccurs="1"/>
2830 </sequence>
2831 <attribute name="full-name" type="xsd:string" use="required"/>
2832 <attribute name="tax-id" type="xsd:unsignedLong" use="required"/>
2833 </complexType>
2834 ~~~
2835 </div>
2836
2837 An example XML instance of `ns__record` is:
2838
2839 <div class="alt">
2840 ~~~{.xml}
2841 <ns:record xmlns:ns="urn:types" full-name="Joe" tax-id="1234567890">
2842 <married-to full-name="Jane" tax-id="1987654320">
2843 </married-to>
2844 </ns:record>
2845 ~~~
2846 </div>
2847
2848 A backtick XML tag name may contain any non-empty sequence of ASCII and UTF-8
2849 characters except white space and the backtick character. A backtick tag can
2850 be combined with member constraints and default member initializers:
2851
2852 ~~~{.cpp}
2853 @ uint64_t SSN `tax-id` 0:1 = 999;
2854 ~~~
2855
2856 🔝 [Back to table of contents](#)
2857
2858 ### Qualified and unqualified members {#toxsd9-6}
2859
2860 Class, struct, and union data members are mapped to namespace qualified or
2861 unqualified tag names of local elements and attributes. If a data member has
2862 no prefix then the default form of qualification is applied based on the
2863 element/attribute form that is declared with the XML schema of the class, struct,
2864 or union type. If the member name has a namespace prefix by colon notation,
2865 then the prefix overrules the default (un)qualified form. Therefore,
2866 [colon notation](#toxsd2) is an effective mechanism to control qualification of
2867 tag names of individual members of classes, structs, and unions.
2868
2869 The XML schema elementFormDefault and attributeFormDefault declarations control
2870 the tag name qualification of local elements and attributes, respectively.
2871
2872 - "unqualified" indicates that local elements/attributes are not qualified with
2873 the namespace prefix.
2874
2875 - "qualified" indicates that local elements/attributes must be qualified with
2876 the namespace prefix.
2877
2878 Individual schema declarations of local elements and attributes may overrule
2879 this by using the form declaration in an XML schema and by using colon notation
2880 to add namespace prefixes to class, struct, and union members in the header
2881 file for soapcpp2.
2882
2883 Consider for example an `ns__record` class in the `ns` namespace in which local
2884 elements are qualified and local attributes are unqualified by default:
2885
2886 ~~~{.cpp}
2887 //gsoap ns schema namespace: urn:types
2888 //gsoap ns schema elementForm: qualified
2889 //gsoap ns schema attributeForm: unqualified
2890 class ns__record
2891 {
2892 public:
2893 @ std::string name;
2894 @ uint64_t SSN;
2895 ns__record *spouse;
2896 };
2897 ~~~
2898
2899 This class maps to a complexType in the soapcpp2-generated XML schema with
2900 targetNamespace "urn:types", elementFormDefault qualified and
2901 attributeFormDefault unqualified:
2902
2903 <div class="alt">
2904 ~~~{.xml}
2905 <schema targetNamespace="urn:types"
2906 ...
2907 elementFormDefault="qualified"
2908 attributeFormDefault="unqualified"
2909 ... >
2910 <complexType name="record">
2911 <sequence>
2912 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1"/>
2913 </sequence>
2914 <attribute name="name" type="xsd:string" use="required"/>
2915 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2916 </complexType>
2917 </schema>
2918 ~~~
2919 </div>
2920
2921 An example XML instance of `ns__record` is:
2922
2923 <div class="alt">
2924 ~~~{.xml}
2925 <ns:record xmlns:ns="urn:types" name="Joe" SSN="1234567890">
2926 <ns:spouse> name="Jane" SSN="1987654320">
2927 </ns:spouse>
2928 </ns:record>
2929 ~~~
2930 </div>
2931
2932 Here the root element <i>`<ns:record>`</i> is qualified because it is a root
2933 element of the XML schema with target namespace "urn:types". Its local element
2934 <i>`<ns:spouse>`</i> is namespace qualified because the elementFormDefault of
2935 local elements is qualified. Attributes are unqualified.
2936
2937 The default namespace (un)qualification of local elements and attributes can be
2938 overruled by adding a prefix to the member name by using colon notation:
2939
2940 ~~~{.cpp}
2941 //gsoap ns schema namespace: urn:types
2942 //gsoap ns schema elementForm: qualified
2943 //gsoap ns schema attributeForm: unqualified
2944 class ns__record
2945 {
2946 public:
2947 @ std::string ns:name; // 'ns:' qualified
2948 @ uint64_t SSN;
2949 ns__record *:spouse; // ':' unqualified (empty prefix)
2950 };
2951 ~~~
2952
2953 The colon notation for member <i>`ns:name`</i> forces qualification of its attribute
2954 tag in XML. The colon notation for member <i>`:spouse`</i> removes qualification from
2955 its local element tag:
2956
2957 <div class="alt">
2958 ~~~{.xml}
2959 <schema targetNamespace="urn:types"
2960 ...
2961 elementFormDefault="unqualified"
2962 attributeFormDefault="unqualified"
2963 ... >
2964 <complexType name="record">
2965 <sequence>
2966 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1" form="unqualified"/>
2967 </sequence>
2968 <attribute name="name" type="xsd:string" use="required" form="qualified"/>
2969 <attribute name="SSN" type="xsd:unsignedLong" use="required"/>
2970 </complexType>
2971 </schema>
2972 ~~~
2973 </div>
2974
2975 XML instances of `ns__record` have unqualified spouse elements and qualified
2976 ns:name attributes:
2977
2978 <div class="alt">
2979 ~~~{.xml}
2980 <ns:record xmlns:ns="urn:types" ns:name="Joe" SSN="1234567890">
2981 <spouse> ns:name="Jane" SSN="1987654320">
2982 </spouse>
2983 </ns:record>
2984 ~~~
2985 </div>
2986
2987 Members of a class or struct can also be prefixed using the `prefix__name`
2988 convention or using colon notation `prefix:name`. However, this has a
2989 different effect by referring to global (root) elements and attributes, see
2990 [document root element definitions](#toxsd9-7).
2991
2992 [Backtick XML tags](#toxsd9-5-1) can be used in place of the member name
2993 annotations and will achieve the same effect as described when these tag names
2994 are (un)qualified (requires gSOAP 2.8.30 or greater).
2995
2996 @note You must declare a target namespace with a `//gsoap ns schema namespace:`
2997 directive to enable the `elementForm` and `attributeForm` directives in order
2998 to generate valid XML schemas with soapcpp2. See [directives](#directives) for
2999 more details.
3000
3001 🔝 [Back to table of contents](#)
3002
3003 ### Defining document root elements {#toxsd9-7}
3004
3005 To define and reference XML document root elements we use type names that start
3006 with an underscore:
3007
3008 ~~~{.cpp}
3009 class _ns__record
3010 ~~~
3011
3012 Alternatively, we can use a `typedef` to define a document root element with a
3013 given type:
3014
3015 ~~~{.cpp}
3016 typedef ns__record _ns__record;
3017 ~~~
3018
3019 This `typedef` maps to a global root element that is added to the
3020 soapcpp2-generated XML schema:
3021
3022 <div class="alt">
3023 ~~~{.xml}
3024 <element name="record" type="ns:record"/>
3025 ~~~
3026 </div>
3027
3028 An example XML instance of `_ns__record` is:
3029
3030 <div class="alt">
3031 ~~~{.xml}
3032 <ns:record xmlns:ns="urn:types">
3033 <name>Joe</name>
3034 <SSN>1234567890</SSN>
3035 <spouse>
3036 <name>Jane</name>
3037 <SSN>1987654320</SSN>
3038 </spouse>
3039 </ns:record>
3040 ~~~
3041 </div>
3042
3043 Global-level element/attribute definitions are also referenced and/or added to
3044 the generated XML schema when serializable data members reference these by
3045 their qualified name:
3046
3047 ~~~{.cpp}
3048 typedef std::string _ns__name 1 : 100;
3049 class _ns__record
3050 {
3051 public:
3052 @ _QName xsi__type; // built-in XSD attribute xsi:type
3053 _ns__name ns__name; // ref to global ns:name element
3054 uint64_t SSN;
3055 _ns__record *spouse;
3056 };
3057 ~~~
3058
3059 These types map to the following comonents in the soapcpp2-generated XML
3060 schema:
3061
3062 <div class="alt">
3063 ~~~{.xml}
3064 <simpleType name="name">
3065 <restriction base="xsd:string">
3066 <minLength value="1"/>
3067 <maxLength value="100"/>
3068 </restriction>
3069 </simpleType>
3070 <element name="name" type="ns:name"/>
3071 <complexType name="record">
3072 <sequence>
3073 <element ref="ns:name" minOccurs="1" maxOccurs="1"/>
3074 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3075 <element name="spouse" type="ns:record" minOccurs="0" maxOccurs="1"/>
3076 </sequence>
3077 <attribute ref="xsi:type" use="optional"/>
3078 </complexType>
3079 <element name="record" type="ns:record"/>
3080 ~~~
3081 </div>
3082
3083 Use only use qualified member names when their types match the global-level
3084 element types that they refer to. For example:
3085
3086 ~~~{.cpp}
3087 typedef std::string _ns__name; // global element ns:name of type xsd:string
3088 class _ns__record
3089 {
3090 public:
3091 int ns__name; // BAD: global element ns:name is NOT type int
3092 _ns__record ns__record; // OK: ns:record is a global-level root element
3093 ...
3094 };
3095 ~~~
3096
3097 Therefore, we recommend to use qualified member names only when necessary to
3098 refer to standard XSD elements and attributes, such as `xsi__type`, and
3099 `xsd__lang`.
3100
3101 By contrast, colon notation has the desired effect to (un)qualify local tag
3102 names by overruling the default element/attribute namespace qualification, see
3103 [qualified and unqualified members](#toxsd9-6).
3104
3105 As an alternative to prefixing member names, use the backtick tag (requires
3106 gSOAP 2.8.30 or greater):
3107
3108 ~~~{.cpp}
3109 typedef std::string _ns__name 1 : 100;
3110 class _ns__record
3111 {
3112 public:
3113 @ _QName t <i>`xsi:type`</i>; // built-in XSD attribute xsi:type
3114 _ns__name s <i>`ns:name`</i>; // ref to global ns:name element
3115 uint64_t SSN;
3116 _ns__record *spouse;
3117 };
3118 ~~~
3119
3120 🔝 [Back to table of contents](#)
3121
3122 ### (Smart) pointer members and their occurrence constraints {#toxsd9-8}
3123
3124 A public pointer-typed data member is serialized by following its (smart)
3125 pointer(s) to the value pointed to. To serialize pointers to dynamic arrays of
3126 data, please see the next section on
3127 [container and array members and their occurrence constraints](#toxsd9-9).
3128
3129 Pointers that are NULL and smart pointers that are empty are serialized to
3130 produce omitted element and attribute values, unless an element is required
3131 and is nillable (struct/class members marked with `nullptr`) in which case the
3132 element is rendered as an empty element with <i>`xsi:nil="true"`</i>.
3133
3134 To control the occurrence requirements of pointer-based data members,
3135 occurrence constraints are associated with data members in the form of a range
3136 `minOccurs : maxOccurs`. For non-repeatable (meaning, not a container or array)
3137 data members, there are only three reasonable occurrence constraints:
3138
3139 - `0:0` means that this element or attribute is prohibited.
3140
3141 - `0:1` means that this element or attribute is optional.
3142
3143 - `1:1` means that this element or attribute is required.
3144
3145 Pointer-based data members have a default `0:1` occurrence constraint, making
3146 them optional, and their XML schema local element/attribute definition is
3147 marked as nillable. Non-pointer data members have a default `1:1` occurence
3148 constraint, making them required.
3149
3150 A `nullptr` occurrence constraint may be applicable to required elements that
3151 are nillable pointer types, thus `nullptr 1:1`. This indicates that the
3152 element is nillable (can be `NULL` or `nullptr`). A pointer data member that
3153 is explicitly marked as required and nillable with `nullptr 1:1` will be
3154 serialized as an element with an <i>`xsi:nil`</i> attribute, thus effectively
3155 revealing the NULL property of its value.
3156
3157 A non-pointer data member that is explicitly marked as optional with `0:1` will
3158 be set to its default value when no XML value is presented to the deserializer.
3159 A default value can be assigned to a data member that has a primitive type or
3160 is a (smart) pointer to primitive type.
3161
3162 Consider for example:
3163
3164 ~~~{.cpp}
3165 class ns__record
3166 {
3167 public:
3168 std::shared_ptr<std::string> name; // optional (pointer means minOccurs=0)
3169 uint64_t SSN 0:1 = 999; // force optional with default 999
3170 ns__record *spouse nullptr 1:1; // force required and nillabe when absent
3171 };
3172 ~~~
3173
3174 This class maps to a complexType in the soapcpp2-generated XML schema:
3175
3176 <div class="alt">
3177 ~~~{.xml}
3178 <complexType name="record">
3179 <sequence>
3180 <element name="name" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3181 <element name="SSN" type="xsd:unsignedLong" minOccurs="0" maxOccurs="1" default="999"/>
3182 <element name="spouse" type="ns:record" minOccurs="1" maxOccurs="1" nillable="true"/>
3183 </sequence>
3184 </complexType>
3185 ~~~
3186 </div>
3187
3188 An example XML instance of `ns__record` with its `name` string value set to
3189 `Joe`, `SSN` set to its default, and `spouse` set to NULL:
3190
3191 <div class="alt">
3192 ~~~{.xml}
3193 <ns:record xmlns:ns="urn:types" ...>
3194 <name>Joe</name>
3195 <SSN>999</SSN>
3196 <spouse xsi:nil="true"/>
3197 </ns:record>
3198 ~~~
3199 </div>
3200
3201 @note In general, a smart pointer is simply declared as a `volatile` template
3202 in a interface header file for soapcpp2:
3203 ~~~{.cpp}
3204 volatile template <class T> class NAMESPACE::shared_ptr;
3205 ~~~
3206
3207 @note The soapcpp2 tool generates code that uses `NAMESPACE::shared_ptr` and
3208 `NAMESPACE::make_shared` to create shared pointers to objects, where
3209 `NAMESPACE` is any valid C++ namespace such as `std` and `boost` if you have
3210 Boost installed.
3211
3212 🔝 [Back to table of contents](#)
3213
3214 ### Container and array members and their occurrence constraints {#toxsd9-9}
3215
3216 Class and struct data member types that are containers `std::deque`,
3217 `std::list`, `std::vector` and `std::set` are serialized as a collection of
3218 the values they contain. You can also serialize dynamic arrays, which is the
3219 alternative for C to store collections of data. Let's start with STL containers.
3220
3221 You can use `std::deque`, `std::list`, `std::vector`, and `std::set` containers
3222 by importing:
3223
3224 ~~~{.cpp}
3225 #import "import/stl.h" // import all containers
3226 #import "import/stldeque.h" // import deque
3227 #import "import/stllist.h" // import list
3228 #import "import/stlvector.h" // import vector
3229 #import "import/stlset.h" // import set
3230 ~~~
3231
3232 For example, to use a vector data mamber to store names in a record:
3233
3234 ~~~{.cpp}
3235 #import "import/stlvector.h"
3236 class ns__record
3237 {
3238 public:
3239 std::vector<std::string> names;
3240 uint64_t SSN;
3241 };
3242 ~~~
3243
3244 To limit the number of names in the vector within reasonable bounds, occurrence
3245 constraints are associated with the container. Occurrence constraints are of
3246 the form `minOccurs : maxOccurs`:
3247
3248 ~~~{.cpp}
3249 #import "import/stlvector.h"
3250 class ns__record
3251 {
3252 public:
3253 std::vector<std::string> names 1:10;
3254 uint64_t SSN;
3255 };
3256 ~~~
3257
3258 This class maps to a complexType in the soapcpp2-generated XML schema:
3259
3260 <div class="alt">
3261 ~~~{.xml}
3262 <complexType name="record">
3263 <sequence>
3264 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="10"/>
3265 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3266 </sequence>
3267 </complexType>
3268 ~~~
3269 </div>
3270
3271 @note In general, a container is simply declared as a template in an interface
3272 header file for soapcpp2. All class templates are considered containers
3273 (except when declared `volatile`, see smart pointers). For example,
3274 `std::vector` is declared in <i>`gsoap/import/stlvector.h`</i> as:
3275 ~~~{.cpp}
3276 template <class T> class std::vector;
3277 ~~~
3278
3279 @note You can define and use your own containers. The soapcpp2 tool generates
3280 code that uses the following members of the `template <typename T> class C`
3281 container:
3282 ~~~{.cpp}
3283 void C::clear()
3284 C::iterator C::begin()
3285 C::const_iterator C::begin() const
3286 C::iterator C::end()
3287 C::const_iterator C::end() const
3288 size_t C::size() const
3289 C::iterator C::insert(C::iterator pos, const T& val)
3290 ~~~
3291
3292 @note For more details see the example `simple_vector` container with
3293 documentation in the package under <i>`gsoap/samples/template`</i>.
3294
3295 Because C does not support a container template library, we can use a
3296 dynamically-sized array of values. This array is declared as a size-pointer
3297 pair of members within a struct or class. The array size information is stored
3298 in a special size tag member with the name `__size` or `__sizeX`, where `X` can
3299 be any name, or by an `$int` member to identify the member as a special size
3300 tag:
3301
3302 ~~~{.cpp}
3303 struct ns__record
3304 {
3305 $ int sizeofnames; // array size
3306 char* *names; // array of char* names
3307 uint64_t SSN;
3308 };
3309 ~~~
3310
3311 This struct maps to a complexType in the soapcpp2-generated XML schema:
3312
3313 <div class="alt">
3314 ~~~{.xml}
3315 <complexType name="record">
3316 <sequence>
3317 <element name="name" type="xsd:string" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
3318 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3319 </sequence>
3320 </complexType>
3321 ~~~
3322 </div>
3323
3324 To limit the number of names in the array within reasonable bounds, occurrence
3325 constraints are associated with the array size member. Occurrence constraints
3326 are of the form `minOccurs : maxOccurs`:
3327
3328 ~~~{.cpp}
3329 struct ns__record
3330 {
3331 $ int sizeofnames 1:10; // array size 1..10
3332 char* *names; // array of one to ten char* names
3333 uint64_t SSN;
3334 };
3335 ~~~
3336
3337 This struct maps to a complexType in the soapcpp2-generated XML schema:
3338
3339 <div class="alt">
3340 ~~~{.xml}
3341 <complexType name="record">
3342 <sequence>
3343 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="10" nillable="true"/>
3344 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3345 </sequence>
3346 </complexType>
3347 ~~~
3348 </div>
3349
3350 Arrays can also be declared as nested elements, similar to SOAP-encoded dynamic arrays, and these arrays can be used with or without SOAP applications. This requires a separate struct or class with the name of the SOAP array, which should not be qualified with a namespace prefix:
3351
3352 ~~~{.cpp}
3353 struct ArrayOfstring
3354 {
3355 char* *__ptr 1:100; // array of 1..100 strings
3356 int __size; // array size
3357 };
3358 struct ns__record
3359 {
3360 struct ArrayOfstring names; // array of char* names
3361 uint64_t SSN;
3362 };
3363 ~~~
3364
3365 The `ns__record` struct maps to a complexType that references the <i>`ArrayOfstring`</i> complexType with an sequence of 1 to 100 <i>`item`</i> elements:
3366
3367 <div class="alt">
3368 ~~~{.xml}
3369 <complexType name="ArrayOfstring">
3370 <sequence>
3371 <element name="item" type="xsd:string" minOccurs="1" maxOccurs="100"/>
3372 </sequence>
3373 </complexType>
3374 <complexType name="record">
3375 <sequence>
3376 <element name="names" type="ns:ArrayOfstring" minOccurs="1" maxOccurs="1"/>
3377 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3378 </sequence>
3379 </complexType>
3380 ~~~
3381 </div>
3382
3383 To change the <i>`item`</i> element name in the WSDL, XML schema, and XML messages, use `__ptrName` where `Name` is the name you want to use.
3384
3385 @note When <b>`soapcpp2 -e`</b> option <b>`-e`</b> is used, the <i>`ArrayOfstring`</i> becomes a SOAP-encoded array for SOAP 1.1/1.2 RPC encoded messaging:
3386 <div class="alt">
3387 ~~~{.xml}
3388 <import namespace="http://schemas.xmlsoap.org/soap/encoding/"/>
3389 <complexType name="ArrayOfstring">
3390 <complexContent>
3391 <restriction base="SOAP-ENC:Array">
3392 <sequence>
3393 <element name="item" type="xsd:string" minOccurs="1" maxOccurs="100"/>
3394 </sequence>
3395 <attribute ref="SOAP-ENC:arrayType" WSDL:arrayType="xsd:string[]"/>
3396 </restriction>
3397 </complexContent>
3398 </complexType>
3399 <complexType name="record">
3400 <sequence>
3401 <element name="names" type="ns:ArrayOfstring" minOccurs="1" maxOccurs="1"/>
3402 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3403 </sequence>
3404 </complexType>
3405 ~~~
3406 </div>
3407
3408 Fixed-size arrays can be used to store a fixed number of values:
3409
3410 ~~~{.cpp}
3411 struct ns__record
3412 {
3413 char* names[10]; // array of 10 char* names
3414 uint64_t SSN;
3415 };
3416 ~~~
3417
3418 The fixed-size array is similar to a SOAP-encoded array, which can be used with or without SOAP applications. This struct maps to a complexType that references a <i>`Array10Ofstring`</i> complexType with ten <i>`item`</i> elements:
3419
3420 <div class="alt">
3421 ~~~{.xml}
3422 <complexType name="record">
3423 <sequence>
3424 <element name="names" type="ns:Array10Ofstring" minOccurs="1" maxOccurs="1"/>
3425 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3426 </sequence>
3427 </complexType>
3428 <complexType name="Array10Ofstring">
3429 <sequence>
3430 <element name="item" type="xsd:string" minOccurs="0" maxOccurs="10"/>
3431 </sequence>
3432 </complexType>
3433 ~~~
3434 </div>
3435
3436 @note When <b>`soapcpp2 -e`</b> option <b>`-e`</b> is used, the <i>`Array10Ofstring`</i> becomes a SOAP-encoded array for SOAP 1.1/1.2 RPC encoded messaging, see previous note.
3437
3438 🔝 [Back to table of contents](#)
3439
3440 ### Sequencing with hidden members {#toxsd9-10}
3441
3442 A member becomes a hidden XML element, i.e. not visibly rendered in XML, when
3443 its name starts with a double underscore. This makes it possible to sequence a
3444 collection of data members, basically by forming a sequence of elements that
3445 can be optional or repeated together.
3446
3447 To create a sequence of members that are optional, use a pointer-based hidden
3448 member that is a struct with the collection of members to sequence:
3449
3450 ~~~{.cpp}
3451 struct ns__record
3452 {
3453 std::string name; // required name
3454 struct __ns__optional
3455 {
3456 uint64_t SSN; // SSN in optional group
3457 std::string phone; // phone number in optional group
3458 } *__optional; // optional group
3459 };
3460 ~~~
3461
3462 Here we used a hidden struct type `__ns__optional` which starts with a double
3463 underscore, because we do not want to define a new global type for the XML
3464 schema we generate. We just need a unique name for a structure that sequences
3465 the two members.
3466
3467 This struct maps to a complexType in the soapcpp2-generated XML schema:
3468
3469 <div class="alt">
3470 ~~~{.xml}
3471 <complexType name="record">
3472 <sequence>
3473 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3474 <sequence minOccurs="0" maxOccurs="1">
3475 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3476 <element name="phone" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3477 </sequence>
3478 </sequence>
3479 </complexType>
3480 ~~~
3481 </div>
3482
3483 The `name` member is a required element of the <i>`ns:record`</i> complexType.
3484 The <i>`ns:record`</i> complexType has an optional sequence of `SSN` and
3485 `phone` elements.
3486
3487 To create repetitions of a sequence of members, use an array as follows:
3488
3489 ~~~{.cpp}
3490 struct ns__record
3491 {
3492 std::string name; // required name
3493 $ int sizeofarray; // size of group array
3494 struct __ns__array
3495 {
3496 uint64_t SSN; // SSN in group
3497 std::string phone; // phone number in group
3498 } *__array; // group array
3499 };
3500 ~~~
3501
3502 This struct maps to a complexType in the soapcpp2-generated XML schema:
3503
3504 <div class="alt">
3505 ~~~{.xml}
3506 <complexType name="record">
3507 <sequence>
3508 <element name="name" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3509 <sequence minOccurs="0" maxOccurs="unbounded">
3510 <element name="SSN" type="xsd:unsignedLong" minOccurs="1" maxOccurs="1"/>
3511 <element name="phone" type="xsd:string" minOccurs="1" maxOccurs="1"/>
3512 </sequence>
3513 </sequence>
3514 </complexType>
3515 ~~~
3516 </div>
3517
3518 The `name` member is a required element of the <i>`ns:record`</i> complexType.
3519 The <i>`ns:record`</i> complexType has a potentially unbounded sequence of
3520 `SSN` and `phone` elements. You can specify array bounds instead of zero to
3521 unbounded, see [container and array members and their occurrence constraints](#toxsd9-9).
3522
3523 The XML value space consists of a sequence of SSN and phone elements:
3524
3525 <div class="alt">
3526 ~~~{.xml}
3527 <ns:record>
3528 <name>numbers</name>
3529 <SSN>1234567890</SSN>
3530 <phone>555-123-4567</phone>
3531 <SSN>1987654320</SSN>
3532 <phone>555-789-1234</phone>
3533 <SSN>2345678901</SSN>
3534 <phone>555-987-6543</phone>
3535 </ns:record>
3536 ~~~
3537 </div>
3538
3539 🔝 [Back to table of contents](#)
3540
3541 ### Tagged union members {#toxsd9-11}
3542
3543 A union member in a class or in a struct cannot be serialized unless a
3544 discriminating *variant selector* member is provided that tells the serializer
3545 which union field to serialize. This effectively creates a *tagged union*.
3546
3547 The variant selector is associated with the union as a selector-union pair of members.
3548 The variant selector is a member with the name `__union` or `__unionX`, where
3549 `X` can be any name, or by an `$int` member to identify the member as a variant
3550 selector tag:
3551
3552 ~~~{.cpp}
3553 class ns__record
3554 {
3555 public:
3556 $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3557 union ns__choice
3558 {
3559 float x;
3560 int n;
3561 char *s;
3562 } u;
3563 std::string name;
3564 };
3565 ~~~
3566
3567 The variant selector values are auto-generated based on the union name `choice`
3568 and the names of its members `x`, `n`, and `s`:
3569
3570 - `xORnORs = SOAP_UNION_ns__choice_x` when `u.x` is valid.
3571
3572 - `xORnORs = SOAP_UNION_ns__choice_n` when `u.n` is valid.
3573
3574 - `xORnORs = SOAP_UNION_ns__choice_s` when `u.s` is valid.
3575
3576 - `xORnORs = 0` when none are valid (should only be used with great care,
3577 because XSD validation may fail when content is required but absent).
3578
3579 This class maps to a complexType with a sequence and choice in the
3580 soapcpp2-generated XML schema:
3581
3582 <div class="alt">
3583 ~~~{.xml}
3584 <complexType name="record">
3585 <sequence>
3586 <choice>
3587 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3588 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3589 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3590 </choice>
3591 <element name="names" type="xsd:string" minOccurs="1" maxOccurs="1" nillable="true"/>
3592 </sequence>
3593 </complexType>
3594 ~~~
3595 </div>
3596
3597 An STL container or dynamic array of a union requires wrapping the variant
3598 selector and union member in a struct:
3599
3600 ~~~{.cpp}
3601 class ns__record
3602 {
3603 public:
3604 std::vector<
3605 struct ns__data // data with a choice of x, n, or s
3606 {
3607 $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3608 union ns__choice
3609 {
3610 float x;
3611 int n;
3612 char *s;
3613 } u;
3614 }> data; // vector with data
3615 };
3616 ~~~
3617
3618 and an equivalent definition with a dynamic array instead of a `std::vector`
3619 (you can use this in C with structs):
3620
3621 ~~~{.cpp}
3622 class ns__record
3623 {
3624 public:
3625 $ int sizeOfdata; // size of dynamic array
3626 struct ns__data // data with a choice of x, n, or s
3627 {
3628 $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3629 union ns__choice
3630 {
3631 float x;
3632 int n;
3633 char *s;
3634 } u;
3635 } *data; // points to the data array of length sizeOfdata
3636 };
3637 ~~~
3638
3639 This maps to two complexTypes in the soapcpp2-generated XML schema:
3640
3641 <div class="alt">
3642 ~~~{.xml}
3643 <complexType name="data">
3644 <choice>
3645 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3646 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3647 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3648 </choice>
3649 </complexType>
3650 <complexType name="record">
3651 <sequence>
3652 <element name="data" type="ns:data" minOccurs="0" maxOccurs="unbounded"/>
3653 </sequence>
3654 </complexType>
3655 ~~~
3656 </div>
3657
3658 The XML value space consists of a sequence of item elements each wrapped in an
3659 data element:
3660
3661 <div class="alt">
3662 ~~~{.xml}
3663 <ns:record xmlns:ns="urn:types" ...>
3664 <data>
3665 <n>123</n>
3666 </data>
3667 <data>
3668 <x>3.1</x>
3669 </data>
3670 <data>
3671 <s>hello</s>
3672 </data>
3673 <data>
3674 <s>world</s>
3675 </data>
3676 </ns:record>
3677 ~~~
3678 </div>
3679
3680 To remove the wrapping data element, simply rename the wrapping struct to
3681 `__ns__data` and the member to `__data` to make this member invisible to the
3682 serializer. The double underscore prefix naming convention is used for the
3683 struct name and member name. Also use a dynamic array instead of a STL
3684 container (so you can also use this approach in C with structs):
3685
3686 ~~~{.cpp}
3687 class ns__record
3688 {
3689 public:
3690 $ int sizeOfdata; // size of dynamic array
3691 struct __ns__data // contains choice of x, n, or s
3692 {
3693 $ int xORnORs; // variant selector with values SOAP_UNION_fieldname
3694 union ns__choice
3695 {
3696 float x;
3697 int n;
3698 char *s;
3699 } u;
3700 } *__data; // points to the data array of length sizeOfdata
3701 };
3702 ~~~
3703
3704 This maps to a complexType in the soapcpp2-generated XML schema:
3705
3706 <div class="alt">
3707 ~~~{.xml}
3708 <complexType name="record">
3709 <sequence minOccurs="0" maxOccurs="unbounded">
3710 <choice>
3711 <element name="x" type="xsd:float" minOccurs="1" maxOccurs="1"/>
3712 <element name="n" type="xsd:int" minOccurs="1" maxOccurs="1"/>
3713 <element name="s" type="xsd:string" minOccurs="0" maxOccurs="1" nillable="true"/>
3714 </choice>
3715 </sequence>
3716 </complexType>
3717 ~~~
3718 </div>
3719
3720 The XML value space consists of a sequence of <i>`<x>`</i>, <i>`<n>`</i>, and/or <i>`<s>`</i>
3721 elements:
3722
3723 <div class="alt">
3724 ~~~{.xml}
3725 <ns:record xmlns:ns="urn:types" ...>
3726 <n>123</n>
3727 <x>3.1</x>
3728 <s>hello</s>
3729 <s>world</s>
3730 </ns:record>
3731 ~~~
3732 </div>
3733
3734 Please note that structs, classes, and unions are unnested by soapcpp2 (as in
3735 the C standard of nested structs and unions). Therefore, the `ns__choice`
3736 union in the `ns__record` class is redeclared at the top level despite its
3737 nesting within the `ns__record` class. This means that you will have to choose
3738 a unique name for each nested struct, class, and union.
3739
3740 🔝 [Back to table of contents](#)
3741
3742 ### Tagged void pointer members {#toxsd9-12}
3743
3744 To serialize data pointed to by `void*` requires run-time type information that
3745 tells the serializer what type of data to serialize by means of a *tagged void
3746 pointer*. This type information is stored in a special type tag member of a
3747 struct/class with the name `__type` or `__typeX`, where `X` can be any name, or
3748 alternatively by an `$int` special member of any name as a type tag:
3749
3750 ~~~{.cpp}
3751 class ns__record
3752 {
3753 public:
3754 $ int typeOfdata; // type tag with values SOAP_TYPE_T
3755 void *data; // points to some data of type T
3756 };
3757 ~~~
3758
3759 A type tag member has nonzero values `SOAP_TYPE_T` where `T` is the name of a
3760 struct/class or the name of a primitive type, such as `int`, `std__string` (for
3761 `std::string`), `string` (for `char*`).
3762
3763 This class maps to a complexType with a sequence in the soapcpp2-generated
3764 XML schema:
3765
3766 <div class="alt">
3767 ~~~{.xml}
3768 <complexType name="record">
3769 <sequence>
3770 <element name="data" type="xsd:anyType" minOccurs="0" maxOccurs="1"/>
3771 </sequence>
3772 </complexType>
3773 ~~~
3774 </div>
3775
3776 The XML value space consists of the XML value space of the type with the
3777 addition of an <i>`xsi:type`</i> attribute to the enveloping element:
3778
3779 <div class="alt">
3780 ~~~{.xml}
3781 <ns:record xmlns:ns="urn:types" ...>
3782 <data xsi:type="xsd:int">123</data>
3783 </ns:record>
3784 ~~~
3785 </div>
3786
3787 This <i>`xsi:type`</i> attribute is important for the receiving end to distinguish
3788 the type of data to instantiate. The receiver cannot deserialize the data
3789 without an <i>`xsd:type`</i> attribute.
3790
3791 You can find the `SOAP_TYPE_T` name of each serializable type in the
3792 auto-generated <i>`soapStub.h`</i> file.
3793
3794 Also all serializable C++ classes have a virtual `int T::soap_type()` member
3795 that returns their `SOAP_TYPE_T` value that you can use.
3796
3797 When the `void*` pointer is NULL or when `typeOfdata` is zero, the data is not
3798 serialized.
3799
3800 An STL container or dynamic array of `void*` pointers to <i>`xsd:anyType`</i> data
3801 requires wrapping the type tag and `void*` members in a struct:
3802
3803 ~~~{.cpp}
3804 class ns__record
3805 {
3806 public:
3807 std::vector<
3808 struct ns__data // data with an xsd:anyType item
3809 {
3810 $ int typeOfitem; // type tag with values SOAP_TYPE_T
3811 void *item; // points to some item of type T
3812 }> data; // vector with data
3813 };
3814 ~~~
3815
3816 and an equivalent definition with a dynamic array instead of a `std::vector`
3817 (you can use this in C with structs):
3818
3819 ~~~{.cpp}
3820 class ns__record
3821 {
3822 public:
3823 $ int sizeOfdata; // size of dynamic array
3824 struct ns__data // data with an xsd:anyType item
3825 {
3826 $ int typeOfitem; // type tag with values SOAP_TYPE_T
3827 void *item; // points to some item of type T
3828 } *data; // points to the data array of length sizeOfdata
3829 };
3830 ~~~
3831
3832 This maps to two complexTypes in the soapcpp2-generated XML schema:
3833
3834 <div class="alt">
3835 ~~~{.xml}
3836 <complexType name="data">
3837 <sequence>
3838 <element name="item" type="xsd:anyType" minOccurs="1" maxOccurs="1" nillable="true"/>
3839 </sequence>
3840 </complexType>
3841 <complexType name="record">
3842 <sequence>
3843 <element name="data" type="ns:data" minOccurs="0" maxOccurs="unbounded"/>
3844 </sequence>
3845 </complexType>
3846 ~~~
3847 </div>
3848
3849 The XML value space consists of a sequence of item elements each wrapped in a
3850 data element:
3851
3852 <div class="alt">
3853 ~~~{.xml}
3854 <ns:record xmlns:ns="urn:types" ...>
3855 <data>
3856 <item xsi:type="xsd:int">123</item>
3857 </data>
3858 <data>
3859 <item xsi:type="xsd:double">3.1</item>
3860 </data>
3861 <data>
3862 <item xsi:type="xsd:string">abc</item>
3863 </data>
3864 </ns:record>
3865 ~~~
3866 </div>
3867
3868 To remove the wrapping data elements, simply rename the wrapping struct and
3869 member to `__data` to make this member invisible to the serializer with the
3870 double underscore prefix naming convention. Also use a dynamic array instead
3871 of a STL container (you can use this in C with structs):
3872
3873 ~~~{.cpp}
3874 class ns__record
3875 {
3876 public:
3877 $ int sizeOfdata; // size of dynamic array
3878 struct __data // contains xsd:anyType item
3879 {
3880 $ int typeOfitem; // type tag with values SOAP_TYPE_T
3881 void *item; // points to some item of type T
3882 } *__data; // points to the data array of length sizeOfdata
3883 };
3884 ~~~
3885
3886 This maps to a complexType in the soapcpp2-generated XML schema:
3887
3888 <div class="alt">
3889 ~~~{.xml}
3890 <complexType name="record">
3891 <sequence minOccurs="0" maxOccurs="unbounded">
3892 <element name="item" type="xsd:anyType" minOccurs="1" maxOccurs="1"/>
3893 </sequence>
3894 </complexType>
3895 ~~~
3896 </div>
3897
3898 The XML value space consists of a sequence of data elements:
3899
3900 <div class="alt">
3901 ~~~{.xml}
3902 <ns:record xmlns:ns="urn:types" ...>
3903 <item xsi:type="xsd:int">123</item>
3904 <item xsi:type="xsd:double">3.1</item>
3905 <item xsi:type="xsd:string">abc</item>
3906 </ns:record>
3907 ~~~
3908 </div>
3909
3910 Again, please note that structs, classes, and unions are unnested by soapcpp2
3911 (as in the C standard of nested structs and unions). Therefore, the `__data`
3912 struct in the `ns__record` class is redeclared at the top level despite its
3913 nesting within the `ns__record` class. This means that you will have to choose
3914 a unique name for each nested struct, class, and union.
3915
3916 @see Section [XSD type bindings](#typemap2).
3917
3918 🔝 [Back to table of contents](#)
3919
3920 ### Adding get and set methods {#toxsd9-13}
3921
3922 A public `get` method may be added to a class or struct, which will be
3923 triggered by the deserializer. This method will be invoked right after the
3924 instance is populated by the deserializer. The `get` method can be used to
3925 update or verify deserialized content. It should return `SOAP_OK` or set
3926 `soap::error` to a nonzero error code and return it.
3927
3928 A public `set` method may be added to a class or struct, which will be
3929 triggered by the serializer. The method will be invoked just before the
3930 instance is serialized. Likewise, the `set` method should return `SOAP_OK` or
3931 set set `soap::error` to a nonzero error code and return it.
3932
3933 For example, adding a `set` and `get` method to a class declaration:
3934
3935 ~~~{.cpp}
3936 class ns__record
3937 {
3938 public:
3939 int set(struct soap*); // triggered before serialization
3940 int get(struct soap*); // triggered after deserialization
3941 ...
3942 };
3943 ~~~
3944
3945 To add these and othe rmethods to classes and structs with wsdl2h and
3946 <i>`typemap.dat`</i>, please see [class/struct member additions](#typemap3).
3947
3948 🔝 [Back to table of contents](#)
3949
3950 ### Operations on classes and structs {#toxsd9-14}
3951
3952 The following functions/macros are generated by soapcpp2 for each type `T`,
3953 which should make it easier to send, receive, and copy XML data in C and in
3954 C++:
3955
3956 - `int soap_write_T(struct soap*, T*)` writes an instance of `T` to a file via
3957 file descriptor `int soap::sendfd)` or to a stream via `std::ostream
3958 *soap::os` (C++ only) or saves into a NUL-terminated string by setting
3959 `const char **soap::os` to a string pointer to be set (C only). Returns
3960 `SOAP_OK` on success or an error code, also stored in `soap::error`.
3961
3962 - `int soap_read_T(struct soap*, T*)` reads an instance of `T` from a file via
3963 file descriptor `int soap::recvfd)` or from a stream via `std::istream
3964 *soap::is` (C++ only) or reads from a NUL-termianted string `const char
3965 *soap::is` (C only). Returns `SOAP_OK` on success or an error code, also
3966 stored in `soap::error`.
3967
3968 - `void soap_default_T(struct soap*, T*)` sets an instance `T` to its default
3969 value, resetting members of a struct to their initial values (for classes we
3970 use method `T::soap_default`, see below). If `T` is a struct that has a
3971 `soap` pointer member to a `::soap` context then this pointer member will be
3972 set to the first argument passed to this function to initialize its `soap`
3973 pointer member.
3974
3975 - `T * soap_dup_T(struct soap*, T *dst, const T *src)` (requires <b>`soapcpp2 -Ec`</b>)
3976 deep copy `src` into `dst`, replicating all deep cycles and shared pointers
3977 when a managing `soap` context is provided as argument. When `dst` is NULL,
3978 allocates space for `dst` and returns a pointer to the allocated copy. Deep
3979 copy results in a tree when the `soap` context is NULL, but the presence of
3980 deep cycles will lead to non-termination. Use flag `SOAP_XML_TREE` with
3981 managing context to copy into a tree without cycles and pointers to shared
3982 objects. Returns `dst` or allocated copy when `dst` is NULL.
3983
3984 - `void soap_del_T(const T*)` (requires <b>`soapcpp2 -Ed`</b>) deletes all
3985 heap-allocated members of this object by deep deletion ONLY IF this object
3986 and all of its (deep) members are not managed by a `soap` context AND the deep
3987 structure is a tree (no cycles and co-referenced objects by way of multiple
3988 (non-smart) pointers pointing to the same data). Can be safely used after
3989 `T * soap_dup_T(NULL, NULL, const T*)` to delete the deep copy returned.
3990 Does not delete the object itself.
3991
3992 When in C++ mode, soapcpp2 tool adds several methods to classes in addition to
3993 adding a default constructor and destructor (when these were not explicitly
3994 declared).
3995
3996 The public methods added to a class `T`:
3997
3998 - `virtual int T::soap_type(void)` returns a unique type ID (`SOAP_TYPE_T`).
3999 This numeric ID can be used to distinguish base from derived instances.
4000
4001 - `virtual void T::soap_default(struct soap*)` sets all data members to
4002 default values. If class `T` has a `soap` pointer member to a `::soap`
4003 context then this pointer member will be set to the argument passed to this
4004 function to initialize its `soap` pointer member.
4005
4006 - `virtual void T::soap_serialize(struct soap*) const` serializes object to
4007 prepare for SOAP 1.1/1.2 encoded output (or with `SOAP_XML_GRAPH`) by
4008 analyzing its (cyclic) structures.
4009
4010 - `virtual int T::soap_put(struct soap*, const char *tag, const char *type) const`
4011 emits object in XML, compliant with SOAP 1.1 encoding style, return error
4012 code or `SOAP_OK`. Requires `soap_begin_send(soap)` and
4013 `soap_end_send(soap)`.
4014
4015 - `virtual int T::soap_out(struct soap*, const char *tag, int id, const char *type) const`
4016 emits object in XML, with tag and optional id attribute and <i>`xsi:type`</i>,
4017 return error code or `SOAP_OK`. Requires `soap_begin_send(soap)` and
4018 `soap_end_send(soap)`.
4019
4020 - `virtual void * T::soap_get(struct soap*, const char *tag, const char *type)`
4021 Get object from XML, compliant with SOAP 1.1 encoding style, return pointer
4022 to object or NULL on error. Requires `soap_begin_recv(soap)` and
4023 `soap_end_recv(soap)`.
4024
4025 - `virtual void *soap_in(struct soap*, const char *tag, const char *type)`
4026 Get object from XML, with matching tag and type (NULL matches any tag and
4027 type), return pointer to object or NULL on error. Requires
4028 `soap_begin_recv(soap)` and `soap_end_recv(soap)`
4029
4030 - `virtual T * T::soap_alloc(void) const` returns a new object of type `T`,
4031 default initialized and not managed by a `soap` context.
4032
4033 - `virtual T * T::soap_dup(struct soap*) const` (requires <b>`soapcpp2 -Ec`</b>)
4034 returns a duplicate of this object by deep copying, replicating all deep
4035 cycles and shared pointers when a managing `soap` context is provided as
4036 argument. Deep copy is a tree when argument is NULL, but the presence of
4037 deep cycles will lead to non-termination. Use flag `SOAP_XML_TREE` with the
4038 managing context to copy into a tree without cycles and pointers to shared
4039 objects.
4040
4041 - `virtual void T::soap_del() const` (rquires <b>`soapcpp2 -Ed`</b>) deletes all
4042 heap-allocated members of this object by deep deletion ONLY IF this object
4043 and all of its (deep) members are not managed by a `soap` context AND the deep
4044 structure is a tree (no cycles and co-referenced objects by way of multiple
4045 (non-smart) pointers pointing to the same data). Can be safely used after
4046 `soap_dup(NULL)` to delete the deep copy. Does not delete the object itself.
4047
4048 Also, there are four variations of `soap_new_T` for
4049 class/struct/template type `T` that soapcpp2 auto-generates to create instances
4050 on a context-managed heap:
4051
4052 - `T * soap_new_T(struct soap*)` returns a new instance of `T` with default data
4053 member initializations that are set with the soapcpp2 auto-generated `void
4054 T::soap_default(struct soap*)` method), but ONLY IF the soapcpp2
4055 auto-generated default constructor is used that invokes `soap_default()` and
4056 was not replaced by a user-defined default constructor.
4057
4058 - `T * soap_new_T(struct soap*, int n)` returns an array of `n` new instances of
4059 `T`. Similar to the above, instances are initialized.
4060
4061 - `T * soap_new_req_T(struct soap*, ...)` returns a new instance of `T` and sets
4062 the required data members to the values specified in `...`. The required data
4063 members are those with nonzero minOccurs, see the subsections on
4064 [(smart) pointer members and their occurrence constraints](#toxsd9-8) and
4065 [container and array members and their occurrence constraints](#toxsd9-9).
4066
4067 - `T * soap_new_set_T(struct soap*, ...)` returns a new instance of `T` and sets
4068 the public/serializable data members to the values specified in `...`.
4069
4070 The above functions can be invoked with a NULL `soap` context, but we will be
4071 responsible to use `delete T` to remove this instance from the unmanaged heap.
4072
4073 The allocation functions return NULL when memory allocation failed.
4074
4075 🔝 [Back to table of contents](#)
4076
4077 Special classes and structs {#toxsd10}
4078 ---------------------------
4079
4080 The following applies to both structs and classes. The examples show classes
4081 in C++. For C, use structs and omit the C++ features. Structs also require
4082 the use of the `struct` keyword, otherwise soapcpp2 will throw a syntax error.
4083
4084 ### SOAP-encoded arrays {#toxsd10-1}
4085
4086 A class or struct with the following layout is a one-dimensional SOAP-encoded
4087 array type:
4088
4089 ~~~{.cpp}
4090 class ArrayOfT
4091 {
4092 public:
4093 T *__ptr; // array pointer
4094 int __size; // array size
4095 };
4096 ~~~
4097
4098 where `T` is the array element type. A multidimensional SOAP Array is:
4099
4100 ~~~{.cpp}
4101 class ArrayOfT
4102 {
4103 public:
4104 T *__ptr; // array pointer
4105 int __size[N]; // array size of each dimension
4106 };
4107 ~~~
4108
4109 where `N` is the constant number of dimensions. The pointer points to an array
4110 of `__size[0]*__size[1]* ... * __size[N-1]` elements.
4111
4112 This maps to a complexType restriction of SOAP-ENC:Array in the
4113 soapcpp2-generated XML schema:
4114
4115 <div class="alt">
4116 ~~~{.xml}
4117 <complexType name="ArrayOfT">
4118 <complexContent>
4119 <restriction base="SOAP-ENC:Array">
4120 <sequence>
4121 <element name="item" type="T" minOccurs="0" maxOccurs="unbounded" nillable="true"/>
4122 </sequence>
4123 <attribute ref="SOAP-ENC:arrayType" WSDL:arrayType="ArrayOfT[]"/>
4124 </restriction>
4125 </complexContent>
4126 </complexType>
4127 ~~~
4128 </div>
4129
4130 The name of the class can be arbitrary. We often use `ArrayOfT` without a
4131 prefix to distinguish arrays from other classes and structs.
4132
4133 With SOAP 1.1 encoding, an optional offset member can be added that controls
4134 the start of the index range for each dimension:
4135
4136 ~~~{.cpp}
4137 class ArrayOfT
4138 {
4139 public:
4140 T *__ptr; // array pointer
4141 int __size[N]; // array size of each dimension
4142 int __offset[N]; // array offsets to start each dimension
4143 };
4144 ~~~
4145
4146 For example, we can define a matrix of floats as follows:
4147
4148 ~~~{.cpp}
4149 class Matrix
4150 {
4151 public:
4152 double *__ptr;
4153 int __size[2];
4154 };
4155 ~~~
4156
4157 The following code populates the matrix and serializes it in XML:
4158
4159 ~~~{.cpp}
4160 soap *soap = soap_new1(SOAP_XML_INDENT);
4161 Matrix A;
4162 double a[6] = { 1, 2, 3, 4, 5, 6 };
4163 A.__ptr = a;
4164 A.__size[0] = 2;
4165 A.__size[1] = 3;
4166 soap_write_Matrix(soap, &A);
4167 ~~~
4168
4169 Matrix A is serialized as an array with 2x3 values:
4170
4171 <div class="alt">
4172 ~~~{.xml}
4173 <SOAP-ENC:Array SOAP-ENC:arrayType="xsd:double[2,3]" ...>
4174 <item>1</item>
4175 <item>2</item>
4176 <item>3</item>
4177 <item>4</item>
4178 <item>5</item>
4179 <item>6</item>
4180 </SOAP-ENC:Array>
4181 ~~~
4182 </div>
4183
4184 🔝 [Back to table of contents](#)
4185
4186 ### XSD hexBinary and base64Binary types {#toxsd10-2}
4187
4188 A special case of a one-dimensional array is used to define <i>`xsd:hexBinary`</i> and
4189 <i>`xsd:base64Binary`</i> types when the pointer type is `unsigned char`:
4190
4191 ~~~{.cpp}
4192 class xsd__hexBinary
4193 {
4194 public:
4195 unsigned char *__ptr; // points to raw binary data
4196 int __size; // size of data
4197 };
4198 ~~~
4199
4200 and
4201
4202 ~~~{.cpp}
4203 class xsd__base64Binary
4204 {
4205 public:
4206 unsigned char *__ptr; // points to raw binary data
4207 int __size; // size of data
4208 };
4209 ~~~
4210
4211 To create a new binary type, use either one of the following three forms that
4212 declare a new `ns__binary` type that is a <i>`simpleType`</i> restriction of
4213 <i>`xsd:base64Binary`</i>:
4214
4215 ~~~{.cpp}
4216 typedef xsd__base64Binary ns__binary;
4217 ~~~
4218 ~~~{.cpp}
4219 class ns__binary : public xsd__base64Binary
4220 {
4221 ... // attribute members (@) and class methods
4222 };
4223 ~~~
4224 ~~~{.cpp}
4225 class ns__binary
4226 {
4227 public:
4228 unsigned char *__ptr; // points to raw binary data
4229 int __size; // size of data
4230 ... // attribute members (@) and class methods (optional)
4231 };
4232 ~~~
4233
4234 Here, `xsd__base64Binary` is reused in the first two cases, where
4235 `xsd__base64Binary` is declared as shown above.
4236
4237 @see [DIME/MIME/MTOM attachment binary types](#toxsd10-3)
4238
4239 🔝 [Back to table of contents](#)
4240
4241 ### DIME/MIME/MTOM attachment binary types {#toxsd10-3}
4242
4243 A class or struct with a binary content layout can be extended to support
4244 attachments. The following struct or class type can be used as DIME, MIME, and
4245 MTOM attachment and also be used for <i>`xsd:base64Binary`</i> type values:
4246
4247 ~~~{.cpp}
4248 class xsd__base64Binary
4249 {
4250 public:
4251 unsigned char *__ptr; // points to raw binary data
4252 int __size; // size of data
4253 char *id; // NULL to generate an id, or set to a unique UUID
4254 char *type; // MIME type of the data
4255 char *options; // optional description of MIME attachment
4256 };
4257 ~~~
4258
4259 When the `id`, `type`, or `options` members are non-NULL, an attachment will be
4260 used instead of base64 XML content. DIME attachments are the default. To
4261 switch to MIME use the `SOAP_ENC_MIME` context flag. To switch to MTOM use the
4262 `SOAP_ENC_MTOM` context flag.
4263
4264 MTOM is typically used with XOP <i>`<xop:Include>`</i> elements, which is
4265 preferred and declared as follows:
4266
4267 ~~~{.cpp}
4268 //gsoap xop schema import: http://www.w3.org/2004/08/xop/include
4269 class _xop__Include
4270 {
4271 public:
4272 unsigned char *__ptr; // points to raw binary data
4273 int __size; // size of data
4274 char *id; // NULL to generate an id, or set to a unique UUID
4275 char *type; // MIME type of the data
4276 char *options; // optional description of MIME attachment
4277 };
4278 ~~~
4279
4280 Attachments are beyond the scope of this article. See the
4281 [gSOAP user guide.](../../guide/html/index.html) for more details.
4282
4283 🔝 [Back to table of contents](#)
4284
4285 ### Wrapper class/struct with simpleContent {#toxsd10-4}
4286
4287 A class or struct with the following layout is a complexType that wraps
4288 simpleContent:
4289
4290 ~~~{.cpp}
4291 class ns__simple
4292 {
4293 public:
4294 T __item; // primitive type for the simpleContent
4295 ... // attribute members (@) and class methods (optional)
4296 };
4297 ~~~
4298
4299 The type `T` is a primitive type (`bool`, `enum`, `time_t`, numeric and string
4300 types), `xsd__hexBinary`, `xsd__base64Binary`, and custom serializers, such as
4301 `xsd__dateTime`.
4302
4303 This maps to a complexType with simpleContent in the soapcpp2-generated XML
4304 schema:
4305
4306 <div class="alt">
4307 ~~~{.xml}
4308 <complexType name="simple">
4309 <simpleContent>
4310 <extension base="T"/>
4311 </simpleContent>
4312 </complexType>
4313 ~~~
4314 </div>
4315
4316 A wrapper class/struct may include any number of members that are declared as
4317 attributes with `@`, which should be placed after the `__item` member.
4318
4319 🔝 [Back to table of contents](#)
4320
4321 ### DOM anyType and anyAttribute {#toxsd10-5}
4322
4323 Use of a DOM is optional and enabled by `#import "dom.h"` to use the DOM
4324 `xsd__anyType` element node and `xsd__anyAttribute` attribute node:
4325
4326 ~~~{.cpp}
4327 #import "dom.h"
4328
4329 class ns__record
4330 {
4331 public:
4332 @ xsd__anyAttribute attributes; // optional DOM attributes
4333 xsd__anyType *name; // optional DOM element (pointer means minOccurs=0)
4334 xsd__anyType address; // required DOM element (minOccurs=1)
4335 xsd__anyType email 0; // optional DOM element (minOccurs=0)
4336 ... // other members
4337 };
4338 ~~~
4339
4340 where `name` contains XML stored in a DOM node set and `attributes` is a list
4341 of all visibly rendered attributes. The name `attributes` is arbitrary and any
4342 name will suffice.
4343
4344 You should place the `xsd__anyType` members at the end of the struct or class.
4345 This ensures that the DOM members are populated last as a "catch all". A
4346 member name starting with double underscore is a wildcard member. These
4347 members are placed at the end of a struct or class automatically by soapcpp2.
4348
4349 An `#import "dom.h"` import is automatically added by <b>`wsdl2h -d`</b> with
4350 option <b>`-d`</b> to bind <i>`xsd:anyType`</i> to DOM nodes, and also to
4351 populate <i>`xsd:any`</i>, <i>`xsd:anyAttribute`</i> and <i>`xsd:mixed`</i> XML
4352 content:
4353
4354 ~~~{.cpp}
4355 #import "dom.h"
4356
4357 class ns__record
4358 {
4359 public:
4360 @ xsd__anyAttribute __anyAttribute; // optional DOM attributes
4361 std::vector<xsd__anyType> __any 0; // optional DOM elements (minOccurs=0)
4362 xsd__anyType __mixed 0; // optional mixed content (minOccurs=0)
4363 ... // other members
4364 };
4365 ~~~
4366
4367 where the members prefixed with `__` are "invisible" to the XML parser, meaning
4368 that these members are not bound to XML tag names.
4369
4370 In C you can use a dynamic arrary instead of `std::vector`:
4371
4372 ~~~{.cpp}
4373 #import "dom.h"
4374
4375 struct ns__record
4376 {
4377 @ xsd__anyAttribute __anyAttribute; // optional DOM attributes
4378 $ int __sizeOfany; // size of the array
4379 xsd__anyType *__any; // optional DOM elements (pointer means minOccurs=0)
4380 xsd__anyType __mixed 0; // optional mixed content (minOccurs=0)
4381 ... // other members
4382 };
4383 ~~~
4384
4385 Classes can inherit DOM, which enables full use of polymorphism with one base
4386 DOM class:
4387
4388 ~~~{.cpp}
4389 #import "dom.h"
4390
4391 class ns__record : public xsd__anyType
4392 {
4393 public:
4394 std::vector<xsd__anyType*> array; // array of objects of any class
4395 ... // other members
4396 };
4397 ~~~
4398
4399 This permits an `xsd__anyType` pointer to refer to a derived class such as
4400 `ns__record`, which will be serialized with an <i>`xsi:type`</i> attribute that is
4401 set to "ns:record". The <i>`xsi:type`</i> attributes add the necessary type information
4402 to distinguish the XML content from the DOM base type. This is important for
4403 the receiving end: without <i>`xsd:type`</i> attributes with type names, only base DOM
4404 objects are recognized and instantiated.
4405
4406 Because C lacks object-oriented programming concepts such as class inheritance
4407 and polymorphism, you should consider using [derived types in C and C++](#toxsd9-1-1).
4408
4409 An alternative is to use the special [tagged void pointer members](#toxsd9-12)
4410 to serialize data pointed to by a `void*` member, which can be any serializable
4411 type, such as derived types. This approach uses <i>`xsi:type`</i> attributes
4412 to identify the type of value serialized.
4413
4414 To ensure that wsdl2h generates pointer-based `xsd__anyType` DOM nodes with
4415 <b>`wsdl2h -d`</b> using option <b>`-d`</b> for <i>`xsd:any`</i>, add the
4416 following line to <i>`typemap.dat`</i>:
4417
4418 xsd__any = | xsd__anyType*
4419
4420 This lets wsdl2h produce class/struct members and containers with
4421 `xsd__anyType*` for <i>`xsd:any`</i> instead of `xsd__anyType`. To just force all
4422 <i>`xsd:anyType`</i> uses to be pointer-based, declare in <i>`typemap.dat`</i>:
4423
4424 xsd__anyType = | xsd__anyType*
4425
4426 If you use <b>`wsdl2h -d -p`</b> using options <b>`-d`</b> and <b>`-p`</b> then
4427 every class will inherit DOM as shown above. Without option `-d`, an
4428 `xsd__anyType` type is generated to serve as the root type in the type
4429 hierarchy:
4430
4431 ~~~{.cpp}
4432 class xsd__anyType { _XML __item; struct soap *soap; };
4433
4434 class ns__record : public xsd__anyType
4435 {
4436 ...
4437 };
4438 ~~~
4439
4440 where the `_XML __item` member holds any XML content as a literal XML string.
4441
4442 To use the DOM API, compile <i>`dom.c`</i> (or <i>`dom.cpp`</i> for C++), or
4443 link the gSOAP library with <b>`-lgsoapssl`</b> (or <b>`-lgsoapssl++`</b> for C++).
4444
4445 @see Documentation of [XML DOM and XPath](http://www.genivia.com/doc/dom/html)
4446 for more details.
4447
4448 🔝 [Back to table of contents](#)
4449
4450 Directives {#directives}
4451 ==========
4452
4453 You can use `//gsoap` directives in the interface header file with the data
4454 binding interface for soapcpp2. These directives are used to configure the
4455 code generated by soapcpp2 by declaring various. properties of Web services
4456 and XML schemas. When using the wsdl2h tool, you will notice that wsdl2h
4457 generates directives automatically based on the WSDL and XSD input.
4458
4459 Service directives are applicable to service and operations described by WSDL.
4460 Schema directives are applicable to types, elements, and attributes defined by
4461 XML schemas.
4462
4463 🔝 [Back to table of contents](#)
4464
4465 Service directives {#directives-1}
4466 ------------------
4467
4468 A service directive must start at a new line and is of the form:
4469
4470 ~~~{.cpp}
4471 //gsoap <prefix> service <property>: <value>
4472 ~~~
4473
4474 where `<prefix>` is the XML namespace prefix of a service binding. The
4475 `<property>` and `<value>` fields are one of the following:
4476
4477 property | value
4478 --------------- | -----
4479 `name` | name of the service, optionally followed by text describing the service
4480 `namespace` | URI of the WSDL targetNamespace
4481 `documentation` | text describing the service (see also the `name` property), multiple permitted
4482 `doc` | an alias for the `documentation` property
4483 `style` | `document` (default) SOAP messaging style or `rpc` for SOAP RPC
4484 `encoding` | `literal` (default), `encoded` for SOAP encoding, or a custom URI
4485 `protocol` | specifies SOAP or REST, see below
4486 `port` | URL of the service endpoint, usually an http or https address, to use in the WSDL definitions/service/port/address/\@location
4487 `location` | an alias for the `port` property
4488 `endpoint` | an alias for the `port` property
4489 `transport` | URI declaration of the transport, usually `http://schemas.xmlsoap.org/soap/http`
4490 `definitions` | name of the WSDL definitions/\@name
4491 `type` | name of the WSDL definitions/portType/\@name (WSDL2.0 interface/\@name)
4492 `portType` | an alias for the `type` property (`portType` follows SOAP 1.1 naming conventions)
4493 `interface` | an alias for the `type` property (`interface` follows SOAP 1.2 naming conventions)
4494 `binding` | name of the WSDL definitions/binding/\@name
4495 `portName` | name of the WSDL definitions/service/port/\@name
4496 `executable` | name of the "executable" to use in the WSDL definitions/service/port/address/\@location
4497
4498 The service `name` and `namespace` properties are required in order to generate
4499 a valid WSDL with soapcpp2. The other properties are optional.
4500
4501 The `style` and `encoding` property defaults are changed with
4502 <b>`soapcpp2 -e`</b> option <b>`-e`</b> to `rpc` and `encoded`, respectively.
4503
4504 The `protocol` property is `SOAP` by default (SOAP 1.1). Protocol property
4505 values are:
4506
4507 protocol value | description
4508 -------------- | -----------
4509 `SOAP` | SOAP transport, supporting both SOAP 1.1 and 1.2
4510 `SOAP1.1` | SOAP 1.1 transport (same as `soapcpp2 -1`)
4511 `SOAP1.2` | SOAP 1.2 transport (same as `soapcpp2 -2`)
4512 `SOAP-GET` | one-way SOAP 1.1 or 1.2 with HTTP GET
4513 `SOAP1.1-GET` | one-way SOAP 1.1 with HTTP GET
4514 `SOAP1.2-GET` | one-way SOAP 1.2 with HTTP GET
4515 `HTTP` | non-SOAP REST protocol with HTTP POST
4516 `POST` | non-SOAP REST protocol with HTTP POST
4517 `GET` | non-SOAP REST protocol with HTTP GET
4518 `PUT` | non-SOAP REST protocol with HTTP PUT
4519 `DELETE` | non-SOAP REST protocol with HTTP DELETE
4520
4521 You can bind service operations to the WSDL namespace of a service by using the
4522 namespace prefix as part of the identifier name of the function that defines
4523 the service operation:
4524
4525 ~~~{.cpp}
4526 int prefix__func(arg1, arg2, ..., argn, result);
4527 ~~~
4528
4529 You can override the `port` endpoint URL at runtime in the auto-generated
4530 `soap_call_prefix__func` service call (C/C++ client side) and in the C++ proxy
4531 class service call.
4532
4533 🔝 [Back to table of contents](#)
4534
4535 Service method directives {#directives-2}
4536 -------------------------
4537
4538 Service properties are applicable to a service and to all of its operations.
4539 Service method directives are specifically applicable to a service operation.
4540
4541 A service method directive is of the form:
4542
4543 ~~~{.cpp}
4544 //gsoap <prefix> service method-<property>: <method> <value>
4545 ~~~
4546
4547 where `<prefix>` is the XML namespace prefix of a service binding and
4548 `<method>` is the unqualified name of a service operation. The `<property>`
4549 and `<value>` fields are one of the following:
4550
4551 method property | value
4552 --------------------------- | -----
4553 `method-documentation` | text describing the service operation
4554 `method` | an alias for the `method-documentation` property
4555 `method-action` | `""` or URI SOAPAction HTTP header, or URL query string for REST protocols
4556 `method-input-action` | `""` or URI SOAPAction HTTP header of service request messages
4557 `method-output-action` | `""` or URI SOAPAction HTTP header of service response messages
4558 `method-fault-action` | `""` or URI SOAPAction HTTP header of service fault messages
4559 `method-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Header
4560 `method-input-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Headers of requests
4561 `method-output-header-part` | member name of the `SOAP_ENV__Header` struct used in SOAP Headers of responses
4562 `method-fault` | type name of a struct or class member used in `SOAP_ENV__Details` struct
4563 `method-mime-type` | REST content type or SOAP MIME attachment content type(s)
4564 `method-input-mime-type` | REST content type or SOAP MIME attachment content type(s) of request message
4565 `method-output-mime-type` | REST content type or SOAP MIME attachment content type(s) of response message
4566 `method-style` | `document` or `rpc`
4567 `method-encoding` | `literal`, `encoded`, or a custom URI for encodingStyle of messages
4568 `method-response-encoding` | `literal`, `encoded`, or a custom URI for encodingStyle of response messages
4569 `method-protocol` | SOAP or REST, see [service directives](#directives-1)
4570
4571 The `method-header-part` properties can be repeated for a service operation to
4572 declare multiple SOAP Header parts that the service operation requires. You
4573 can use `method-input-header-part` and `method-output-header-part` to
4574 differentiate between request and response messages.
4575
4576 The `method-fault` property can be repeated for a service operation to declare
4577 multiple faults that the service operation may return.
4578
4579 The `method-action` property serves two purposes:
4580
4581 -# To set the SOAPAction header for SOAP protocols, i.e. sets the
4582 definitions/binding/operation/SOAP:operation/\@soapAction.
4583
4584 -# To set the URL query string for endpoints with REST protocols, i.e. sets the
4585 definitions/binding/operation/HTTP:operation/\@location, which specifies
4586 a URL query string (starts with a `?`) to complete the service endpoint URL
4587 or extends the endpoint URL with a local path (starts with a `/`).
4588
4589 Use `method-input-action` and `method-output-action` to differentiate the
4590 SOAPAction between SOAP request and response messages.
4591
4592 You can always override the port endpoint URL and action values at runtime in
4593 the auto-generated `soap_call_prefix__func` service call (C/C++ client side)
4594 and in the auto-generated C++ proxy class service calls. A runtime NULL
4595 endpoint URL and/or action uses the defaults set by these directives.
4596
4597 The `method-mime-type` property serves two purposes:
4598
4599 -# To set the type of MIME/MTOM attachments used with SOAP protocols. Multiple
4600 attachment types can be declared for a SOAP service operation, i.e. adds
4601 definitions/binding/operation/input/MIME:multipartRelated/MIME:part/MIME:content/\@type
4602 for each type specified.
4603
4604 -# To set the MIME type of a REST operation. This replaces XML declared in
4605 WSDL by definitions/binding/operation/(input|output)/MIME:mimeXml with
4606 MIME:content/\@type. Use `application/x-www-form-urlencoded` with REST POST
4607 and PUT protocols to send encoded form data automatically instead of XML.
4608 Only primitive type values can be transmitted with form data, such as
4609 numbers and strings, i.e. only types that are legal to use as
4610 [attributes members](#toxsd9-5).
4611
4612 Use `method-input-mime-type` and `method-output-mime-type` to differentiate the
4613 attachment types between request and response messages.
4614
4615 🔝 [Back to table of contents](#)
4616
4617 Schema directives {#directives-3}
4618 -----------------
4619
4620 A schema directive is of the form:
4621
4622 ~~~{.cpp}
4623 //gsoap <prefix> schema <property>: <value>
4624 ~~~
4625
4626 where `<prefix>` is the XML namespace prefix of a schema. The `<property>` and
4627 `<value>` fields are one of the following:
4628
4629 property | value
4630 --------------- | -----
4631 `namespace` | URI of the XSD targetNamespace
4632 `namespace2` | alternate URI pattern for the XSD namespace (i.e. URI is also accepted by the XML parser)
4633 `import` | URI of an imported namespace, as an alternative or in addition to `namespace`, adds `xsd:import` to the generated WSDL and XSD files
4634 `form` | `unqualified` (default) or `qualified` local element and attribute form defaults
4635 `elementForm` | `unqualified` (default) or `qualified` local element form default
4636 `attributeForm` | `unqualified` (default) or `qualified` local attribute form default
4637 `typed` | `no` (default) or `yes` for serializers to add `xsi:type` attributes to XML
4638
4639 To learn more about the local form defaults, see [qualified and unqualified members.](#toxsd9-6)
4640
4641 The `namespace2` URI is a pattern with `*` matching any sequence of characters
4642 and `-` matching any character. This pattern instructs the XML parser and validator
4643 to also accept the URI pattern as a valid namespace for the specified `<prefix>`.
4644
4645 The `typed` property is implicitly `yes` when <b>`soapcpp2 -t`</b> option <b>`-t`</b> is used.
4646
4647 🔝 [Back to table of contents](#)
4648
4649 Schema type directives {#directives-4}
4650 ----------------------
4651
4652 A schema type directive is of the form:
4653
4654 ~~~{.cpp}
4655 //gsoap <prefix> schema type-<property>: <name> <value>
4656 //gsoap <prefix> schema type-<property>: <name>::<member> <value>
4657 ~~~
4658
4659 where `<prefix>` is the XML namespace prefix of a schema and `<name>` is an
4660 unqualified name of a C/C++ type, and the optional `<member>` is a class/struct
4661 members or enum constant.
4662
4663 You can describe a type with one of the following:
4664
4665 type property | value
4666 -------------------- | -----
4667 `type-documentation` | text describing the schema type
4668 `type` | an alias for the `type-documentation` property
4669
4670 For example, you can add a description to an enumeration:
4671
4672 ~~~{.cpp}
4673 //gsoap ns schema type: Vowels The letters A, E, I, O, U, and sometimes Y
4674 //gsoap ns schema type: Vowels::Y A vowel, sometimes
4675 enum class ns__Vowels : char { A = 'A', E = 'E', I = 'I', O = 'O', U = 'U', Y = 'Y' };
4676 ~~~
4677
4678 This documented enumeration maps to a simpleType restriction of <i>`xsd:string`</i> in
4679 the soapcpp2-generated schema:
4680
4681 <div class="alt">
4682 ~~~{.xml}
4683 <simpleType name="Vowels">
4684 <annotation>
4685 <documentation>The letters A, E, I, O, U, and sometimes Y</documentation>
4686 </annotation>
4687 <restriction base="xsd:string">
4688 <enumeration value="A"/>
4689 <enumeration value="E"/>
4690 <enumeration value="I"/>
4691 <enumeration value="O"/>
4692 <enumeration value="U"/>
4693 <enumeration value="Y">
4694 <annotation>
4695 <documentation>A vowel, sometimes</documentation>
4696 </annotation>
4697 <enumeration/>
4698 </restriction>
4699 </simpleType>
4700 ~~~
4701 </div>
4702
4703 🔝 [Back to table of contents](#)
4704
4705 Serialization rules {#rules}
4706 ===================
4707
4708 A presentation on XML data bindings is not complete without discussing the
4709 serialization rules and options that put your data in XML on the wire or store
4710 it a file or buffer.
4711
4712 There are several options to choose from to serialize data in XML. The choice
4713 depends on the use of the SOAP protocol or if SOAP is not required. The wsdl2h
4714 tool automates this for you by taking the WSDL transport bindings into account
4715 when generating the service functions in C and C++ that use SOAP or REST.
4716
4717 The gSOAP tools are not limited to SOAP. The tools implement generic XML data
4718 bindings for SOAP, REST, and other uses of XML. So you can read and write XML
4719 using the serializing [operations on classes and structs](#toxsd9-14).
4720
4721 The following sections briefly explain the serialization rules with respect to
4722 the SOAP protocol for XML Web services. A basic understanding of the SOAP
4723 protocol is useful when developing client and server applications that must
4724 interoperate with other SOAP applications.
4725
4726 SOAP/REST Web service client and service operations are represented as
4727 functions in your interface header file with the data binding interface for
4728 soapcpp2. The soapcpp2 tool will translate these function to client-side
4729 service invocation calls and server-side service operation dispatchers.
4730
4731 A discussion of SOAP clients and servers is beyond the scope of this article.
4732 However, the SOAP options discussed here also apply to SOAP client and server
4733 development.
4734
4735 🔝 [Back to table of contents](#)
4736
4737 SOAP document versus rpc style {#doc-rpc}
4738 ------------------------------
4739
4740 The `wsdl:binding/soap:binding/@style` attribute in the <i>`<wsdl:binding>`</i>
4741 section of a WSDL is either "document" or "rpc". The "rpc" style refers to
4742 SOAP RPC (Remote Procedure Call), which is more restrictive than the "document"
4743 style by requiring one XML element in the SOAP Body to act as the procedure
4744 name with XML subelements as its parameters.
4745
4746 For example, the following directives in the interface header file for soapcpp2
4747 declare that `DBupdate` is a SOAP RPC encoding service method:
4748
4749 ~~~{.cpp}
4750 //gsoap ns service namespace: urn:DB
4751 //gsoap ns service method-protocol: DBupdate SOAP
4752 //gsoap ns service method-style: DBupdate rpc
4753 int ns__DBupdate(...);
4754 ~~~
4755
4756 The XML payload has a SOAP envelope, optional SOAP header, and a SOAP body with
4757 one element representing the operation with the parameters as subelements:
4758
4759 <div class="alt">
4760 ~~~{.xml}
4761 <SOAP-ENV:Envelope
4762 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4763 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4764 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4765 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4766 xmlsn:ns="urn:DB">
4767 <SOAP-ENV:Body>
4768 <ns:DBupdate>
4769 ...
4770 </ns:DBupdate>
4771 </SOAP-ENV:Body>
4772 </SOAP-ENV:Envelope>
4773 ~~~
4774 </div>
4775
4776 The "document" style puts no restrictions on the SOAP Body content. However, we
4777 recommend that the first element's tag name in the SOAP Body should be unique
4778 to each type of operation, so that the receiver can dispatch the operation
4779 based on this element's tag name. Alternatively, the HTTP URL path can be used
4780 to specify the operation, or the HTTP action header can be used to dispatch
4781 operations automatically on the server side (soapcpp2 options -a and -A).
4782
4783 🔝 [Back to table of contents](#)
4784
4785 SOAP literal versus encoding {#lit-enc}
4786 ----------------------------
4787
4788 The `wsdl:operation/soap:body/@use` attribute in the <i>`<wsdl:binding>`</i> section
4789 of a WSDL is either "literal" or "encoded". The "encoded" use refers to the
4790 SOAP encoding rules that support id-ref multi-referenced elements to serialize
4791 data as graphs.
4792
4793 SOAP encoding is very useful if the data internally forms a graph (including
4794 cycles) and we want the graph to be serialized in XML in a format that ensures
4795 that its structure is preserved. In that case, SOAP 1.2 encoding is the best
4796 option.
4797
4798 SOAP encoding also adds encoding rules for [SOAP arrays](#toxsd10) to serialize
4799 multi-dimensional arrays. The use of XML attributes to exchange XML data in
4800 SOAP encoding is not permitted. The only attributes permitted are the standard
4801 XSD attributes, SOAP encoding attributes (such as for arrays), and id-ref.
4802
4803 For example, the following directives in the interface header file for soapcpp2
4804 declare that `DBupdate` is a SOAP RPC encoding service method:
4805
4806 ~~~{.cpp}
4807 //gsoap ns service namespace: urn:DB
4808 //gsoap ns service method-protocol: DBupdate SOAP
4809 //gsoap ns service method-style: DBupdate rpc
4810 //gsoap ns service method-encoding: DBupdate encoded
4811 int ns__DBupdate(...);
4812 ~~~
4813
4814 The XML payload has a SOAP envelope, optional SOAP header, and a SOAP body with
4815 an encodingStyle attribute for SOAP 1.1 encoding and an element representing the
4816 operation with parameters that are SOAP 1.1 encoded:
4817
4818 <div class="alt">
4819 ~~~{.xml}
4820 <SOAP-ENV:Envelope
4821 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4822 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4823 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4824 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4825 xmlsn:ns="urn:DB">
4826 <SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
4827 <ns:DBupdate>
4828 <records SOAP-ENC:arrayType="ns:record[3]">
4829 <item>
4830 <name href="#_1"/>
4831 <SSN>1234567890</SSN>
4832 </item>
4833 <item>
4834 <name>Jane</name>
4835 <SSN>1987654320</SSN>
4836 </item>
4837 <item>
4838 <name href="#_1"/>
4839 <SSN>2345678901</SSN>
4840 </item>
4841 </records>
4842 </ns:DBupdate>
4843 <id id="_1" xsi:type="xsd:string">Joe</id>
4844 </SOAP-ENV:Body>
4845 </SOAP-ENV:Envelope>
4846 ~~~
4847 </div>
4848
4849 In the XML fragment shown above the name "Joe" is shared by two records and the
4850 string is referenced by SOAP 1.1 href and id attributes.
4851
4852 While the soapcpp-generated serializers only introduce multi-referenced
4853 elements in the payload when they are actually multi-referenced in the data
4854 graph, other SOAP applications may render multi-referenced elements more
4855 aggressively. The example could also be rendered as:
4856
4857 <div class="alt">
4858 ~~~{.xml}
4859 <SOAP-ENV:Envelope
4860 xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"
4861 xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/"
4862 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4863 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4864 xmlsn:ns="urn:DB">
4865 <SOAP-ENV:Body SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
4866 <ns:DBupdate>
4867 <records SOAP-ENC:arrayType="ns:record[3]">
4868 <item href="#id1"/>
4869 <item href="#id2"/>
4870 <item href="#id3"/>
4871 </records>
4872 </ns:DBupdate>
4873 <id id="id1" xsi:type="ns:record">
4874 <name href="#id4"/>
4875 <SSN>1234567890</SSN>
4876 </id>
4877 <id id="id2" xsi:type="ns:record">
4878 <name href="#id5"/>
4879 <SSN>1987654320</SSN>
4880 </id>
4881 <id id="id3" xsi:type="ns:record">
4882 <name href="#id4"/>
4883 <SSN>2345678901</SSN>
4884 </id>
4885 <id id="id4" xsi:type="xsd:string">Joe</id>
4886 <id id="id5" xsi:type="xsd:string">Jane</id>
4887 </SOAP-ENV:Body>
4888 </SOAP-ENV:Envelope>
4889 ~~~
4890 </div>
4891
4892 SOAP 1.2 encoding is cleaner and produces more accurate XML encodings of data
4893 graphs by setting the id attribute on the element that is referenced:
4894
4895 <div class="alt">
4896 ~~~{.xml}
4897 <SOAP-ENV:Envelope
4898 xmlns:SOAP-ENV="http://www.w3.org/2003/05/soap-envelope"
4899 xmlns:SOAP-ENC="http://www.w3.org/2003/05/soap-encoding"
4900 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
4901 xmlns:xsd="http://www.w3.org/2001/XMLSchema"
4902 xmlsn:ns="urn:DB">
4903 <SOAP-ENV:Body>
4904 <ns:DBupdate SOAP-ENV:encodingStyle="http://www.w3.org/2003/05/soap-encoding">
4905 <records SOAP-ENC:itemType="ns:record" SOAP-ENC:arraySize="3">
4906 <item>
4907 <name SOAP-ENC:id="_1">Joe</name>
4908 <SSN>1234567890</SSN>
4909 </item>
4910 <item>
4911 <name>Jane</name>
4912 <SSN>1987654320</SSN>
4913 </item>
4914 <item>
4915 <name SOAP-ENC:ref="_1"/>
4916 <SSN>2345678901</SSN>
4917 </item>
4918 </records>
4919 </ns:DBupdate>
4920 </SOAP-ENV:Body>
4921 </SOAP-ENV:Envelope>
4922 ~~~
4923 </div>
4924
4925 @note Some SOAP 1.2 applications consider the namespace `SOAP-ENC` of
4926 <i>`SOAP-ENC:id`</i> and <i>`SOAP-ENC:ref`</i> optional. With gSOAP, the SOAP
4927 1.2 encoding serialization follows the 2007 standard, while accepting
4928 unqualified id and ref attributes.
4929
4930 To remove all rendered id-ref multi-referenced elements, use the
4931 `SOAP_XML_TREE` flag to initialize the `soap` context.
4932
4933 Some XSD validation rules are turned off with SOAP encoding, because of the
4934 presence of additional attributes, such as id and ref/href, SOAP arrays with
4935 arbitrary element tags for array elements, and the occurrence of additional
4936 multi-ref elements in the SOAP 1.1 Body.
4937
4938 The use of "literal" puts no restrictions on the XML in the SOAP Body. Full
4939 XSD validation is possible, which can be enabled with the `SOAP_XML_STRICT`
4940 flag to initialize the `soap` context. However, data graphs will be
4941 serialized as trees and cycles in the data will be cut from the XML rendition.
4942
4943 🔝 [Back to table of contents](#)
4944
4945 SOAP 1.1 versus SOAP 1.2 {#soap}
4946 ------------------------
4947
4948 There are two SOAP protocol versions: 1.1 and 1.2. The gSOAP tools can switch
4949 between the two versions seamlessly. You can declare the default SOAP version
4950 for a service operation as follows:
4951
4952 ~~~{.cpp}
4953 //gsoap ns service method-protocol: DBupdate SOAP1.2
4954 ~~~
4955
4956 Use `SOAP` (SOAP 1.1), `SOAP1.1`, `SOAP1.2`, and `HTTP` to switch SOAP versions
4957 or enable REST methods with HTTP POST. See [service directives](#directives-1)
4958 and [XML serialization](#non-soap).
4959
4960 The soapcpp2 tool auto-generates client and server code. At the client side,
4961 this operation sends data with SOAP 1.2 but accepts responses also in SOAP 1.1.
4962 At the server side, this operation accepts requests in SOAP 1.1 and 1.2 and
4963 will return responses in the same SOAP version.
4964
4965 As we discussed in the previous section, the SOAP 1.2 protocol has a cleaner
4966 multi-referenced element serialization format that greatly enhances the
4967 accuracy of data graph serialization with SOAP RPC encoding and is therefore
4968 recommended.
4969
4970 The SOAP 1.2 protocol default can also be set by importing and loading
4971 <i>`gsoap/import/soap12.h`</i>:
4972
4973 ~~~{.cpp}
4974 #import "soap12.h"
4975 ~~~
4976
4977 Finally, the soapcpp2 tool has options to force SOAP 1.1, SOAP 1.2, or remove
4978 SOAP altogether with <b>`soapcpp2 -1`</b> (SOAP 1.1), <b>`soapcpp2 -2`</b>
4979 (SOAP 1.2) and <b>`soapcpp2 -0`</b> (plain XML, no SOAP).
4980
4981 🔝 [Back to table of contents](#)
4982
4983 XML serialization {#non-soap}
4984 -----------------
4985
4986 You can serialize data to XML that is stored on the heap, on the stack (locals), and
4987 static data as long as the serializable (i.e. non-transient) values are
4988 properly initialized and pointers in the data structures are either NULL or
4989 point to valid structures.
4990
4991 When XML is deserialized into data, the data is put on the heap and managed by the
4992 `::soap` context, see also [memory management](#memory).
4993
4994 You can read and write XML directly to a file or stream with the serializing
4995 [operations on classes and structs](#toxsd9-14).
4996
4997 To define and use XML Web service client and service operations, we can declare
4998 these operations in your interface header file with the data binding interface
4999 for soapcpp2 as functions. The function are translated by soapcpp2 to
5000 client-side service invocation calls and server-side service operation
5001 dispatchers.
5002
5003 The REST operations POST, GET, and PUT are declared with `//gsoap` directives
5004 in the interface header file for soapcpp2. For example, a REST HTTP POST
5005 operation is declared as follows:
5006
5007 ~~~{.cpp}
5008 //gsoap ns service namespace: urn:DB
5009 //gsoap ns service method-protocol: DBupdate POST
5010 int ns__DBupdate(...);
5011 ~~~
5012
5013 There are no SOAP Envelope and SOAP Body elements in the payload for
5014 `DBupdate`. Also the XML serialization rules are identical to SOAP
5015 document/literal, meaning no SOAP RPC encoding XML structures are implicitly
5016 used. The XML payload only has the operation name as an element with its
5017 parameters serialized as subelements:
5018
5019 <div class="alt">
5020 ~~~{.xml}
5021 <ns:DBupdate xmln:ns="urn:DB" ...>
5022 ...
5023 </ns:DBupdate>
5024 ~~~
5025 </div>
5026
5027 To force id-ref serialization with REST similar to SOAP 1.2 multi-reference
5028 encoding, use the `SOAP_XML_GRAPH` flag to initialize the `soap` context.
5029 The XML serialization includes id and ref attributes for multi-referenced
5030 elements as follows:
5031
5032 <div class="alt">
5033 ~~~{.xml}
5034 <ns:DBupdate xmln:ns="urn:DB" ...>
5035 <records>
5036 <item>
5037 <name id="_1">Joe</name>
5038 <SSN>1234567890</SSN>
5039 </item>
5040 <item>
5041 <name>Jane</name>
5042 <SSN>1987654320</SSN>
5043 </item>
5044 <item>
5045 <name ref="_1"/>
5046 <SSN>2345678901</SSN>
5047 </item>
5048 </records>
5049 </ns:DBupdate>
5050 ~~~
5051 </div>
5052
5053 🔝 [Back to table of contents](#)
5054
5055 Input and output {#io}
5056 ================
5057
5058 Reading and writing XML from/to files, streams and string buffers is done via
5059 the managing `soap` context by setting one of the following context variables that
5060 control IO sources and sinks:
5061
5062 ~~~{.cpp}
5063 soap->recvfd = fd; // an int file descriptor to read from (0 by default)
5064 soap->sendfd = fd; // an int file descriptor to write to (1 by default)
5065 soap->is = &is; // C++ only: a std::istream is object to read from
5066 soap->os = &os; // C++ only: a std::ostream os object to write to
5067 soap->is = cs; // C only: a const char* string to read from (soap->is will advance)
5068 soap->os = &cs; // C only: pointer to a const char*, will be set to point to the string output
5069 ~~~
5070
5071 Normally, all of these context variables are NULL, which is required to send and
5072 receive data over sockets by gSOAP client and server applications. Therefore,
5073 if you set any of these context variables in a client or server application
5074 then you should reset them to NULL to ensure that socket communications are not
5075 blocked.
5076
5077 @note The use of `soap::is` and `soap::os` in C requires gSOAP 2.8.28 or greater.
5078
5079 In the following sections, we present more details on how to read and write to
5080 files and streams, and use string buffers as sources and sinks for XML data.
5081
5082 In addition, you can set IO callback functions to handle IO at a lower level.
5083 For more details on defining your own callback functions, see the
5084 [gSOAP user guide.](../../guide/html/index.html)
5085
5086 🔝 [Back to table of contents](#)
5087
5088 Reading and writing from/to files and streams {#io1}
5089 ---------------------------------------------
5090
5091 The default IO is standard input and output. Other sources and sinks (those
5092 listed above) will be used until you (re)set them. For example with file-based
5093 input and output:
5094
5095 ~~~{.cpp}
5096 FILE *fp = fopen("record.xml", "r");
5097 if (fp != NULL)
5098 {
5099 soap->recvfd = fileno(fp); // get file descriptor of file to read from
5100 if (soap_read_ns__record(soap, &pers1))
5101 ... // handle IO error
5102 fclose(fp);
5103 soap->recvfd = 0; // read from stdin, or -1 to block reading
5104 }
5105
5106 FILE *fp = fopen("record.xml", "w");
5107 if (fp != NULL)
5108 {
5109 soap->sendfd = fileno(fp); // get file descriptor of file to write to
5110 if (soap_write_ns__record(soap, &pers1))
5111 ... // handle IO error
5112 fclose(fp);
5113 soap->sendfd = 1; // write to stdout, or -1 to block writing
5114 }
5115 ~~~
5116
5117 Similar code with streams in C++:
5118
5119 ~~~{.cpp}
5120 #include <fstream>
5121
5122 std::fstream fs;
5123 fs.open("record.xml", std::ios::in);
5124 if (fs)
5125 {
5126 soap->is = &fs;
5127 if (soap_read__ns__record(soap, &pers1))
5128 ... // handle IO error
5129 fs.close();
5130 soap->is = NULL;
5131 }
5132
5133 fs.open("record.xml", std::ios::out);
5134 if (fs)
5135 {
5136 soap->os = &fs;
5137 if (soap_write__ns__record(soap, &pers1))
5138 ... // handle IO error
5139 fs.close();
5140 soap->os = NULL;
5141 }
5142 ~~~
5143
5144 🔝 [Back to table of contents](#)
5145
5146 Reading and writing from/to string buffers {#io2}
5147 ------------------------------------------
5148
5149 For C++ we recommend to use `std::stringstream` objects from the
5150 <i>`sstream`</i> C++ library as illustrated in the following example:
5151
5152 ~~~{.cpp}
5153 #include <sstream>
5154
5155 std::stringstream ss;
5156 ss.str("..."); // XML to parse
5157 soap->is = &ss;
5158 if (soap_read__ns__record(soap, &pers1))
5159 ... // handle IO error
5160 soap->is = NULL;
5161
5162 soap->os = &ss;
5163 if (soap_write__ns__record(soap, &pers1))
5164 ... // handle IO error
5165 soap->os = NULL;
5166 std::string s = ss.str(); // string with XML
5167 ~~~
5168
5169 For C we can use `soap::is` and `soap::os` to point to strings of XML content
5170 as follows (this requires gSOAP 2.8.28 or later):
5171
5172 ~~~{.cpp}
5173 soap->is = "..."; // XML to parse
5174 if (soap_read__ns__record(soap, &pers1))
5175 ... // handle IO error
5176 soap->is = NULL;
5177
5178 const char *cs = NULL;
5179 soap->os = &cs;
5180 if (soap_write__ns__record(soap, &pers1))
5181 ... // handle IO error
5182 soap->os = NULL;
5183 ... = cs; // string with XML (do not free(cs): managed by the context and freed with soap_end())
5184 ~~~
5185
5186 The type of `soap::os` is a pointer to a `const char*` string. The pointer is
5187 set by the managing `soap` context to point to the XML data that is stored on
5188 the context-managed heap.
5189
5190 For earlier gSOAP versions we recommend to use IO callbacks `soap::frecv` and
5191 `soap::fsend`, see the [gSOAP user guide.](../../guide/html/index.html).
5192
5193 🔝 [Back to table of contents](#)
5194
5195 Memory management {#memory}
5196 =================
5197
5198 Memory management with the `soap` context enables us to allocate data in
5199 context-managed heap space that can be collectively deleted. All deserialized
5200 data is placed on the context-managed heap by the `soap` context of the engine.
5201
5202 🔝 [Back to table of contents](#)
5203
5204 Memory management in C {#memory1}
5205 ----------------------
5206
5207 When working with gSOAP in C (i.e. using <b>`wsdl2h -c`</b> option <b>`-c`</b>
5208 or <b>`soapcpp2 -c`</b> option <b>`-c`</b>), data is allocated on the managed heap with:
5209
5210 - `void *soap_malloc(struct soap*, size_t len)`.
5211
5212 This function allocates `len` bytes on the heap managed by the specified
5213 context and returns NULL when allocation failed.
5214
5215 You can also make shallow copies of data with `soap_memdup` that uses
5216 `soap_malloc` and a safe version of `memcpy` to copy a chunk of data `src` with
5217 length `len` to the context-managed heap:
5218
5219 - `void * soap_memdup(struct soap*, const void *src, size_t len)`
5220
5221 This function returns a pointer to the copy. This function requires gSOAP
5222 2.8.27 or later.
5223
5224 In gSOAP 2.8.35 and greater versions, you can use an auto-generated function to
5225 allocate and initialize data of type `T` on the managed heap:
5226
5227 - `T * soap_new_T(struct soap*, int n)`
5228
5229 This function returns an array of length `n` of type `T` data that is default
5230 initialized (by internally calling `soap_malloc(soap, n * sizeof(T))` and then
5231 `soap_default_T(soap, T*)` on each array value). Use a negative value or `n=1`
5232 to allocate and initialize a single value. This function returns NULL when
5233 allocation failed.
5234
5235 The `soap_malloc` function is essentially a wrapper around `malloc`, but
5236 permits the `soap` context to track all heap allocations for collective
5237 deletion with `soap_end(soap)`:
5238
5239 ~~~{.cpp}
5240 #include "soapH.h"
5241 #include "ns.nsmap"
5242 ...
5243 struct soap *soap = soap_new(); // new context
5244 ...
5245 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5246 soap_default_ns__record(soap, record); // auto-generated struct initializer
5247 ...
5248 soap_destroy(soap); // only for C++, see section on C++ below
5249 soap_end(soap); // delete record and all other heap allocations
5250 soap_free(soap); // delete context
5251 ~~~
5252
5253 All data on the managed heap is mass-deleted with `soap_end(soap)` which must
5254 be called before `soap_done(soap)` or `soap_free(soap)`, which end the use of
5255 the `soap` context and free the context, respectively. Use
5256 `soap_free(soap)` only when the context is allocated with `soap_new()`. Use
5257 `soap_done(soap)` only when the context is stack allocated (so cannot be
5258 deleted from the heap).
5259
5260 The managed heap is checked for memory leaks at run time when the source code
5261 is compiled with option <b>`-DDEBUG`</b>.
5262
5263 The soapcpp2 auto-generated deserializers in C use `soap_malloc` to allocate
5264 and populate deserialized structures, which are managed by the context for
5265 collective deletion.
5266
5267 To make `char*` and `wchar_t*` string copies to the context-managed heap, we
5268 can use the functions:
5269
5270 - `char *soap_strdup(struct soap*, const char *str)` and
5271
5272 - `wchar_t *soap_wstrdup(struct soap*, const wchar_t *wstr)`.
5273
5274 If your C compiler supports `typeof` then you can use the following macro to
5275 simplify the managed heap allocation and initialization of primitive values:
5276
5277 ~~~{.cpp}
5278 #define soap_assign(soap, lhs, rhs) (*(lhs = (typeof(lhs))soap_malloc(soap, sizeof(*lhs))) = rhs)
5279 ~~~
5280
5281 Pointers to primitive values are often used for optional members. For example,
5282 assume we have the following struct:
5283
5284 ~~~{.cpp}
5285 struct ns__record
5286 {
5287 const char *name 1; // required (minOccurs=1)
5288 uint64_t *SSN; // optional (pointer means minOccurs=0)
5289 struct ns__record *spouse; // optional (pointer means minOccurs=0)
5290 };
5291 ~~~
5292
5293 Use `soap_assign` to create a SSN value on the managed heap:
5294
5295 ~~~{.cpp}
5296 struct soap *soap = soap_new(); // new context
5297 ...
5298 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5299 soap_default_ns__record(soap, record);
5300 record->name = soap_strdup(soap, "Joe");
5301 soap_assign(soap, record->SSN, 1234567890UL);
5302 ...
5303 soap_end(soap); // delete managed soap_malloc'ed heap data
5304 soap_free(soap); // delete context
5305 ~~~
5306
5307 Without the `soap_assign` macro, you will need two lines of code, one to
5308 allocate and one to assign (you should also use this if your system can run out
5309 of memory):
5310
5311 ~~~{.cpp}
5312 assert((record->SSN = (uint64_t*)soap_malloc(soap, sizeof(utint64_t))) != NULL);
5313 *record->SSN = 1234567890UL;
5314 ~~~
5315
5316 The serializer can serialize any heap, stack, or static allocated data. So we
5317 can also create a new record as follows:
5318
5319 ~~~{.cpp}
5320 struct soap *soap = soap_new(); // new context
5321 ...
5322 struct ns__record *record = (struct ns__record*)soap_malloc(soap, sizeof(struct ns__record));
5323 static uint64_t SSN = 1234567890UL;
5324 soap_default_ns__record(soap, record);
5325 record->name = "Joe";
5326 record->SSN = &SSN; // safe to use static values: the value of record->SSN is never changed
5327 ...
5328 soap_end(soap); // delete managed soap_malloc'ed heap data
5329 soap_free(soap); // delete context
5330 ~~~
5331
5332 Use the soapcpp2 auto-generated `soap_dup_T` functions to duplicate data into
5333 another `soap` context (this requires <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to
5334 generate), here shown for C with the second argument `dst` NULL because we want
5335 to allocate a new managed structure:
5336
5337 ~~~{.cpp}
5338 struct soap *other_soap = soap_new(); // another context
5339 struct ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5340 ...
5341 soap_destroy(other_soap); // only for C++, see section on C++ below
5342 soap_end(other_soap); // delete other_record and all of its deep data
5343 soap_free(other_soap); // delete context
5344 ~~~
5345
5346 The only reason to use another `soap` context and not to use the primary `soap`
5347 context is when the primary context must be destroyed together with all of the
5348 objects it manages while some of the objects must be kept alive. If the
5349 objects that are kept alive contain deep cycles then this is the only option we
5350 have, because deep copy with a managing `soap` context detects and preserves
5351 these cycles unless the `SOAP_XML_TREE` flag is used with the `soap` context:
5352
5353 ~~~{.cpp}
5354 struct soap *other_soap = soap_new1(SOAP_XML_TREE); // another context
5355 struct ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5356 ~~~
5357
5358 The resulting deep copy will be a full copy of the source data structure as a
5359 tree without co-referenced data (i.e. no digraph) and without cycles. Cycles
5360 are pruned and (one of the) pointers that forms a cycle is repaced by NULL.
5361
5362 You can also deep copy into unmanaged space and use the auto-generated
5363 `soap_del_T()` function (requires <b>`soapcpp2 -Ed`</b> option <b>`-Ed`</b> to generate) to delete
5364 it later:
5365
5366 ~~~{.cpp}
5367 struct ns__record *other_record = soap_dup_ns__record(NULL, NULL, record);
5368 ...
5369 soap_del_ns__record(other_record); // deep delete record data members
5370 free(other_record); // delete the record
5371 ~~~
5372
5373 But you should not do this for any data that has deep cycles in its runtime
5374 data structure. Cycles in the data structure will lead to non-termination when
5375 making unmanaged deep copies. Consider for example:
5376
5377 ~~~{.cpp}
5378 struct ns__record
5379 {
5380 const char *name 1; // required (minOccurs=1)
5381 uint64_t SSN; // required (non-pointer means minOccurs=1)
5382 struct ns__record *spouse; // optional (pointer means minOccurs=0)
5383 };
5384 ~~~
5385
5386 The code to populate a structure with a mutual spouse relationship:
5387
5388 ~~~{.cpp}
5389 struct soap *soap = soap_new();
5390 ...
5391 struct ns__record pers1, pers2;
5392 soap_default_ns__record(soap, &pers1);
5393 soap_default_ns__record(soap, &pers2);
5394 pers1.name = "Joe"; // OK to serialize static data
5395 pers1.SSN = 1234567890;
5396 pers1.spouse = &pers2;
5397 pers2.name = soap_strdup(soap, "Jane"); // allocates and copies a string
5398 pers2.SSN = 1987654320;
5399 pers2.spouse = &pers1;
5400 ...
5401 struct ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5402 struct ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5403 soap_set_mode(soap, SOAP_XML_TREE);
5404 struct ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5405 ~~~
5406
5407 The bad case is where there is no context used in the first argument. The deep
5408 copy functions use a context to keep track of co-referenced data nodes and
5409 cycles in the data structure copies, to copy co-referenced nodes just once.
5410 Co-references in a data structure are formed by pointers and smart pointers
5411 such as `std::shared_ptr`, such that at least two pointers point to the same
5412 data.
5413
5414 The serializer can serialize any heap, stack, or static allocated data, such as
5415 in the code shown above. So we can serialize the stack-allocated `pers1`
5416 record as follows:
5417
5418 ~~~{.cpp}
5419 FILE *fp = fopen("record.xml", "w");
5420 if (fp != NULL)
5421 {
5422 soap->sendfd = fileno(fp); // file descriptor to write to
5423 soap_set_mode(soap, SOAP_XML_GRAPH); // support id-ref w/o requiring SOAP
5424 soap_clr_mode(soap, SOAP_XML_TREE); // if set, clear
5425 soap_write_ns__record(soap, &pers1);
5426 fclose(fp);
5427 soap->sendfd = -1; // block further writing
5428 }
5429 ~~~
5430
5431 which produces an XML document record.xml that is similar to:
5432
5433 <div class="alt">
5434 ~~~{.xml}
5435 <ns:record xmlns:ns="urn:types" id="Joe">
5436 <name>Joe</name>
5437 <SSN>1234567890</SSN>
5438 <spouse id="Jane">
5439 <name>Jane</name>
5440 <SSN>1987654320</SSN>
5441 <spouse ref="#Joe"/>
5442 </spouse>
5443 </ns:record>
5444 ~~~
5445 </div>
5446
5447 Deserialization of an XML document with a SOAP 1.1/1.2 encoded id-ref graph
5448 leads to the same non-termination problem when we later try to copy the data
5449 into unmanaged memory heap space:
5450
5451 ~~~{.cpp}
5452 struct soap *soap = soap_new1(SOAP_XML_GRAPH); // support id-ref w/o SOAP
5453 ...
5454 struct ns__record pers1;
5455 FILE *fp = fopen("record.xml", "r");
5456 if (fp != NULL)
5457 {
5458 soap->recvfd = fileno(fp);
5459 if (soap_read_ns__record(soap, &pers1))
5460 ... // handle IO error
5461 fclose(fp);
5462 soap->recvfd = -1; // blocks further reading
5463 }
5464 ...
5465 struct ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5466 struct ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5467 soap_set_mode(soap, SOAP_XML_TREE);
5468 struct ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5469 ~~~
5470
5471 Copying data with `soap_dup_T(soap)` into managed heap memory space is always
5472 safe. Copying into unmanaged heap memory space requires diligence. But
5473 deleting unmanaged data is easy with `soap_del_T()`.
5474
5475 You can also use `soap_del_T()` to delete structures that you created in C, but
5476 only if these structures are created with `malloc` and do NOT contain pointers
5477 to stack and static data.
5478
5479 You can unlink one or more allocated objects from the managed heap to allow the
5480 object to live after `soap_end(soap)` by using:
5481
5482 - `void soap_unlink(struct soap *soap, void *ptr)`
5483
5484 The unlinked heap-allocated data pointed to by `ptr` can be accessed after
5485 `soap_end(soap)`. Do not forget to free the data with `free(ptr)`. Be aware
5486 that `soap_unlink(soap, ptr)` does not perform a deep unlinkage. If `ptr` is a
5487 struct, pointer members will become invalid when pointing to objects on the
5488 managed heap. Use `soap_unlink(soap, ptr->member)` to unlink `member` as well.
5489
5490 Finally, when data is allocated in managed memory heap space, either explicitly
5491 with the allocation functions shown above or by the soapcpp2-generated
5492 deserializers, you can delegate the management and deletion of this data to
5493 another `soap` context. That context will be responsible to delete the data
5494 with `soap_end(soap)` later:
5495
5496 - `void delegate_deletion(struct soap *soap_from, struct soap *soap_to)`
5497
5498 This allows the `soap_from` context to be deleted with `soap_free(soap_from)`
5499 (assuming it is allocated with `soap_new()`, use `soap_done(soap_from)` when
5500 `soap_from` is stack-allocated) while the managed data remains intact. You
5501 can use this function any time, to delegate management and deletion to another
5502 context `soap_to` and then continue with the current context. You can also use
5503 different source `soap_from` contexts to delegate management and deletion to
5504 the other `soap_to` context. To mass delete all managed data, use
5505 `soap_end(soap_to)`.
5506
5507 🔝 [Back to table of contents](#)
5508
5509 Memory management in C++ {#memory2}
5510 ------------------------
5511
5512 When working with gSOAP in C++, the engine allocates data on a managed heap
5513 using `soap_new_T(soap)` to allocate a type with type name `T`. Managed heap
5514 allocation is tracked by the `soap` context for collective deletion with
5515 `soap_destroy(soap)` for structs, classes, and templates and with
5516 `soap_end(soap)` for everything else.
5517
5518 You should only use `soap_malloc(struct soap*, size_t len)` to allocate
5519 primitive types because constructors are not invoked. Therefore, `soap_new_T`
5520 is preferred. The auto-generated `T * soap_new_T(struct soap*)` returns data
5521 allocated on the managed heap for type `T`. The data is mass-deleted with
5522 `soap_destroy(soap)` followed by `soap_end(soap)`.
5523
5524 The `soap_new_T` functions return NULL when allocation fails. C++ exceptions
5525 are never raised by the engine and serializers when data is allocated.
5526
5527 There are four variations of `soap_new_T` functions to allocate data of type
5528 `T` that soapcpp2 auto-generates:
5529
5530 - `T * soap_new_T(struct soap*)` returns a new instance of `T` that is default
5531 initialized. For classes, initialization is internally performed using the
5532 soapcpp2 auto-generated `void T::soap_default(struct soap*)` method of the
5533 class, but ONLY IF the soapcpp2 auto-generated default constructor is used
5534 that invokes `soap_default()` and was not replaced by a user-defined default
5535 constructor.
5536
5537 - `T * soap_new_T(struct soap*, int n)` returns an array of `n` new instances of
5538 `T`. The instances in the array are default initialized as described above.
5539
5540 - `T * soap_new_req_T(struct soap*, ...)` (structs and classes only) returns a
5541 new instance of `T` and sets the required data members to the values
5542 specified in `...`. The required data members are those with nonzero
5543 minOccurs, see the subsections on
5544 [(smart) pointer members and their occurrence constraints](#toxsd9-8) and
5545 [container and array members and their occurrence constraints](#toxsd9-9).
5546
5547 - `T * soap_new_set_T(struct soap*, ...)` (structs and classes only) returns a
5548 new instance of `T` and sets the public/serializable data members to the values
5549 specified in `...`.
5550
5551 The above functions can be invoked with a NULL `soap` context, but you are then
5552 responsible to use `delete T` to remove this instance from the unmanaged heap.
5553
5554 For example, to allocate a managed `std::string` you can use:
5555
5556 ~~~{.cpp}
5557 std::string *s = soap_new_std__string(soap);
5558 ~~~
5559
5560 To throw a `std::bad_alloc` exception when memory allocation fails, we can define the
5561 following class and macro:
5562
5563 ~~~{.cpp}
5564 class alloc_check {
5565 public:
5566 template<typename T>
5567 T operator=(T ptr)
5568 {
5569 if (ptr == NULL)
5570 throw std::bad_alloc();
5571 return ptr;
5572 }
5573 };
5574
5575 #define CHECK alloc_check() =
5576 ~~~
5577
5578 And use `CHECK` as follows to throw an exception when memory allocation fails:
5579
5580 ~~~{.cpp}
5581 std::string *s = CHECK soap_new_std__string(soap);
5582 ~~~
5583
5584 To throw a `std::runtime_exception` when memory allocation fails, with file
5585 and line number information where the error occurred, we can define the
5586 following revised version of our exception-throwing macro:
5587
5588 ~~~{.cpp}
5589 class alloc_failure : public std::runtime_error {
5590 public:
5591 alloc_failure(const char *file, size_t line) : std::runtime_error(error(file, line))
5592 { }
5593 private:
5594 std::string error(const char *file, size_t line) const
5595 {
5596 std::stringstream ss;
5597 ss << "Memory allocation failed in " << file << " at line " << line;
5598 return ss.str();
5599 }
5600 };
5601
5602 class alloc_check_with_info {
5603 public:
5604 alloc_check_with_info(const char *file, size_t line) : file(file), line(line)
5605 { }
5606 template<typename T>
5607 T operator=(T ptr) const
5608 {
5609 if (ptr == NULL)
5610 throw alloc_failure(file, line);
5611 return ptr;
5612 }
5613 const char *file;
5614 size_t line;
5615 };
5616
5617 #define CHECK alloc_check_with_info(__FILE__, __LINE__) =
5618 ~~~
5619
5620 And use `CHECK` as follows to throw an exception with the file and line number
5621 of the location where memory allocation failed:
5622
5623 ~~~{.cpp}
5624 std::string *s = CHECK soap_new_std__string(soap);
5625 ~~~
5626
5627 Primitive types and arrays of primitive values may be allocated with
5628 `soap_malloc` (actually, `soap_new_T` calls `soap_malloc` for primitive type
5629 `T`). All primitive types (i.e. no classes, structs, class templates,
5630 containers, and smart pointers) are allocated with `soap_malloc` for reasons of
5631 efficiency.
5632
5633 You can use a C++ template to simplify the managed allocation and initialization
5634 of primitive values as follows (this is for primitive types only):
5635
5636 ~~~{.cpp}
5637 template<class T>
5638 T * soap_make(struct soap *soap, T val)
5639 {
5640 T *p = (T*)soap_malloc(soap, sizeof(T));
5641 if (p == NULL)
5642 throw std::bad_alloc();
5643 *p = val;
5644 return p;
5645 }
5646 ~~~
5647
5648 For example, assuming we have the following class:
5649
5650 ~~~{.cpp}
5651 class ns__record
5652 {
5653 public:
5654 std::string name; // required (non-pointer means minOccurs=1)
5655 uint64_t *SSN; // optional (pointer means minOccurs=0)
5656 ns__record *spouse; // optional (pointer means minOccurs=0)
5657 };
5658 ~~~
5659
5660 You can instantiate a record by using the auto-generated
5661 `soap_new_set_ns__record` and use `soap_make` to create a SSN value on the
5662 managed heap as follows:
5663
5664 ~~~{.cpp}
5665 soap *soap = soap_new(); // new context
5666 ...
5667 ns__record *record = soap_new_set_ns__record(
5668 soap,
5669 "Joe",
5670 soap_make<uint64_t>(soap, 1234567890UL),
5671 NULL);
5672 ...
5673 soap_destroy(soap); // delete record and all other managed instances
5674 soap_end(soap); // delete managed soap_malloc'ed heap data
5675 soap_free(soap); // delete context
5676 ~~~
5677
5678 All data on the managed heap is mass-deleted with `soap_end(soap)` which must
5679 be called before `soap_done(soap)` or `soap_free(soap)`, which end the use of
5680 the `soap` context and free the context, respectively. Use
5681 `soap_free(soap)` only when the context is allocated with `soap_new()`. Use
5682 `soap_done(soap)` only when the context is stack allocated (so cannot be
5683 deleted from the heap).
5684
5685 The managed heap is checked for memory leaks at run time when the source code
5686 is compiled with option <b>`-DDEBUG`</b>.
5687
5688 However, the serializer can serialize any heap, stack, or static allocated
5689 data. So we can also create a new record as follows:
5690
5691 ~~~{.cpp}
5692 uint64_t SSN = 1234567890UL;
5693 ns__record *record = soap_new_set_ns__record(soap, "Joe", &SSN, NULL);
5694 ~~~
5695
5696 which will be fine to serialize this record as long as the local `SSN`
5697 stack-allocated value remains in scope when invoking the serializer and/or
5698 using `record`. It does not matter if `soap_destroy` and `soap_end` are called
5699 beyond the scope of `SSN`.
5700
5701 To facilitate class methods to access the managing context, we can add a soap
5702 context pointer to a class/struct:
5703
5704 ~~~{.cpp}
5705 class ns__record
5706 {
5707 public:
5708 ...
5709 void create_more(); // needs a context to create more internal data
5710 protected:
5711 struct soap *soap; // the context that manages this instance, or NULL
5712 };
5713 ~~~
5714
5715 The `soap` context pointer member of the class is set when invoking
5716 `soap_new_T` (and similar) with a non-NULL context argument that will be
5717 assigned to the `soap` member of the class.
5718
5719 You can also use a template when an array of pointers to values is required.
5720 To create an array of pointers to values, define the following template:
5721
5722 ~~~{.cpp}
5723 template<class T>
5724 T **soap_make_array(struct soap *soap, T* array, int n) throw (std::bad_alloc)
5725 {
5726 T **p = (T**)soap_malloc(soap, n * sizeof(T*));
5727 if (p == NULL)
5728 throw std::bad_alloc();
5729 for (int i = 0; i < n; ++i)
5730 p[i] = &array[i];
5731 return p;
5732 }
5733 ~~~
5734
5735 The `array` parameter is a pointer to an array of `n` values. The template
5736 returns an array of `n` pointers that point to the values in that array:
5737
5738 ~~~{.cpp}
5739 // create an array of 100 pointers to 100 records
5740 int n = 100;
5741 ns__record **precords = soap_make_array(soap, soap_new_ns__record(soap, n), n);
5742 for (int i = 0; i < n; ++i)
5743 {
5744 precords[i]->name = "...";
5745 precords[i]->SSN = soap_make<uint64_t>(1234567890UL + i);
5746 }
5747 ~~~
5748
5749 Note that `soap_new_ns__record(soap, n)` returns a pointer to an array of `n`
5750 records, which is then used to create an array of `n` pointers to these records.
5751
5752 Use the soapcpp2 auto-generated `soap_dup_T` functions to duplicate data into
5753 another `soap` context (this requires <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to generate), here shown
5754 for C++ with the second argument `dst` NULL to allocate a new managed object:
5755
5756 ~~~{.cpp}
5757 soap *other_soap = soap_new(); // another context
5758 ns__record *other_record = soap_dup_ns__record(other_soap, NULL, record);
5759 ...
5760 soap_destroy(other_soap); // delete record and other managed instances
5761 soap_end(other_soap); // delete other data (the SSNs on the heap)
5762 soap_free(other_soap); // delete context
5763 ~~~
5764
5765 To duplicate base and derived instances when a base class pointer or reference
5766 is provided, use the auto-generated method `T * T::soap_dup(struct soap*)`:
5767
5768 ~~~{.cpp}
5769 soap *other_soap = soap_new(); // another context
5770 ns__record *other_record = record->soap_dup(other_soap);
5771 ...
5772 soap_destroy(other_soap); // delete record and other managed instances
5773 soap_end(other_soap); // delete other data (the SSNs on the heap)
5774 soap_free(other_soap); // delete context
5775 ~~~
5776
5777 The only reason to use another context and not to use the primary `soap`
5778 context is when the primary context must be destroyed together with all of the
5779 objects it manages while some of the objects must be kept alive. If the
5780 objects that are kept alive contain deep cycles then this is the only option we
5781 have, because deep copy with a managing `soap` context detects and preserves
5782 these cycles unless the `SOAP_XML_TREE` flag is used with the context:
5783
5784 ~~~{.cpp}
5785 soap *other_soap = soap_new1(SOAP_XML_TREE); // another context
5786 ns__record *other_record = record->soap_dup(other_soap); // deep tree copy
5787 ~~~
5788
5789 The resulting deep copy will be a full copy of the source data structure as a
5790 tree without co-referenced data (i.e. no digraph) and without cycles. Cycles
5791 are pruned and (one of the) pointers that forms a cycle is repaced by NULL.
5792
5793 You can also deep copy into unmanaged space and use the auto-generated
5794 `soap_del_T()` function or the `T::soap_del()` method (requires
5795 <b>`soapcpp2 -Ec`</b> option <b>`-Ec`</b> to generate) to delete it later,
5796 but we should not do this for any data that has deep cycles in its runtime data
5797 structure graph:
5798
5799 ~~~{.cpp}
5800 ns__record *other_record = record->soap_dup(NULL);
5801 ...
5802 other_record->soap_del(); // deep delete record data members
5803 delete other_record; // delete the record
5804 ~~~
5805
5806 Cycles in the data structure will lead to non-termination when making unmanaged
5807 deep copies. Consider for example:
5808
5809 ~~~{.cpp}
5810 class ns__record
5811 {
5812 public:
5813 const char *name 1; // required (minOccurs=1)
5814 uint64_t SSN; // required (non-pointer means minOccurs=1)
5815 ns__record *spouse; // optional (pointer means minOccurs=1)
5816 };
5817 ~~~
5818
5819 The code to populate a structure with a mutual spouse relationship:
5820
5821 ~~~{.cpp}
5822 soap *soap = soap_new();
5823 ...
5824 ns__record pers1, pers2;
5825 pers1.name = "Joe";
5826 pers1.SSN = 1234567890;
5827 pers1.spouse = &pers2;
5828 pers2.name = "Jane";
5829 pers2.SSN = 1987654320;
5830 pers2.spouse = &pers1;
5831 ...
5832 ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5833 ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5834 soap_set_mode(soap, SOAP_XML_TREE);
5835 ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5836 ~~~
5837
5838 The serializer can serialize any heap, stack, or static allocated data, such as
5839 shown in the code shown above. So we can serialize the stack-allocated `pers1`
5840 record as follows:
5841
5842 ~~~{.cpp}
5843 FILE *fp = fopen("record.xml", "w");
5844 if (fp != NULL)
5845 {
5846 soap->sendfd = fileno(fp); // file descriptor to write to
5847 soap_set_mode(soap, SOAP_XML_GRAPH); // support id-ref w/o requiring SOAP
5848 soap_clr_mode(soap, SOAP_XML_TREE); // if set, clear
5849 if (soap_write_ns__record(soap, &pers1))
5850 ... // handle IO error
5851 fclose(fp);
5852 soap->sendfd = -1; // block further writing
5853 }
5854 ~~~
5855
5856 which produces an XML document record.xml that is similar to:
5857
5858 <div class="alt">
5859 ~~~{.xml}
5860 <ns:record xmlns:ns="urn:types" id="Joe">
5861 <name>Joe</name>
5862 <SSN>1234567890</SSN>
5863 <spouse id="Jane">
5864 <name>Jane</name>
5865 <SSN>1987654320</SSN>
5866 <spouse ref="#Joe"/>
5867 </spouse>
5868 </ns:record>
5869 ~~~
5870 </div>
5871
5872 Deserialization of an XML document with a SOAP 1.1/1.2 encoded id-ref graph
5873 leads to the same non-termination problem when we later try to copy the data
5874 into unmanaged space:
5875
5876 ~~~{.cpp}
5877 soap *soap = soap_new1(SOAP_XML_GRAPH); // support id-ref w/o SOAP
5878 ...
5879 ns__record pers1;
5880 FILE *fp = fopen("record.xml", "r");
5881 if (fp != NULL)
5882 {
5883 soap->recvfd = fileno(fp); // file descriptor to read from
5884 if (soap_read_ns__record(soap, &pers1))
5885 ... // handle IO error
5886 fclose(fp);
5887 soap->recvfd = -1; // block further reading
5888 }
5889 ...
5890 ns__record *pers3 = soap_dup_ns__record(NULL, NULL, &pers1); // BAD
5891 ns__record *pers4 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5892 soap_set_mode(soap, SOAP_XML_TREE);
5893 ns__record *pers5 = soap_dup_ns__record(soap, NULL, &pers1); // OK
5894 ~~~
5895
5896 Copying data with `soap_dup_T(soap)` into managed space is always safe. Copying
5897 into unmanaged space requires diligence. But deleting unmanaged data is easy
5898 with `soap_del_T()`.
5899
5900 You can also use `soap_del_T()` to delete structures in C++, but only if these
5901 structures are created with `new` (and `new []` for arrays when applicable) for
5902 classes, structs, and class templates and with `malloc` for anything else, and
5903 the structures do NOT contain pointers to stack and static data.
5904
5905 You can unlink one or more allocated objects from the managed heap to allow the
5906 object to live after `soap_destroy(soap)` and `soap_end(soap)` by using:
5907
5908 - `void soap_unlink(struct soap *soap, void *ptr)`
5909
5910 The unlinked heap-allocated data pointed to by `ptr` can be accessed after
5911 `soap_destroy(soap)` and `soap_end(soap)`. Do not forget to free the data with
5912 `delete ptr` (C++ class instance only) or with `free(ptr)` (non-class data).
5913 Be aware that `soap_unlink(soap, ptr)` does not perform a deep unlinkage. If
5914 `ptr` is a struct or class, pointer members will become invalid when pointing
5915 to objects on the managed heap. Use `soap_unlink(soap, ptr->member)` to unlink
5916 `member` as well.
5917
5918 Finally, when data is allocated in managed memory heap space, either explicitly
5919 with the allocation functions shown above or by the soapcpp2-generated
5920 deserializers, you can delegate the management and deletion of this data to
5921 another `soap` context. That context will be responsible to delete the data
5922 with `soap_destroy(soap)` and `soap_end(soap)` later:
5923
5924 - `void delegate_deletion(struct soap *soap_from, struct soap *soap_to)`
5925
5926 This allows the `soap_from` context to be deleted with `soap_free(soap_from)`
5927 (assuming it is allocated with `soap_new()`, use `soap_done(soap_from)` when
5928 `soap_from` is stack-allocated) while the managed data remains intact. You
5929 can use this function any time, to delegate management and deletion to another
5930 context `soap_to` and then continue with the current context. You can also use
5931 different source `soap_from` contexts to delegate management and deletion to
5932 the other `soap_to` context. To mass delete all managed data, use
5933 `soap_destroy(soap_to)` followed by `soap_end(soap_to)`.
5934
5935 🔝 [Back to table of contents](#)
5936
5937 Context flags to initialize the soap struct {#flags}
5938 ===========================================
5939
5940 There are several `soap` context initialization flags and context mode flags to
5941 control XML serialization at runtime. The flags are set with `soap_new1()` to
5942 allocate and initialize a new context:
5943
5944 ~~~{.cpp}
5945 struct soap *soap = soap_new1(flag1 | flag2 | ... | flagn);
5946 ...
5947 soap_destroy(soap); // delete objects
5948 soap_end(soap); // delete other data and temp data
5949 soap_free(soap); // free context
5950 ~~~
5951
5952 and with `soap_init1()` for stack-allocated contexts:
5953
5954 ~~~{.cpp}
5955 struct soap soap;
5956 soap_init1(&soap, flag1 | flag2 | ... | flagn);
5957 ...
5958 soap_destroy(&soap); // delete objects
5959 soap_end(&soap); // delete other data and temp data
5960 soap_done(&soap); // clear context
5961 ~~~
5962
5963 where `flag1`, `flag2`, ..., `flagn` is one of:
5964
5965 - `SOAP_C_UTFSTRING`: enables all `std::string` and `char*` strings to
5966 contain UTF-8 content. This option is recommended.
5967
5968 - `SOAP_C_NILSTRING`: treat empty strings as if they were NULL pointers, i.e.
5969 omits elements and attributes when empty.
5970
5971 - `SOAP_XML_STRICT`: strictly validates XML while deserializing. Should not be
5972 used together with SOAP 1.1/1.2 encoding style of messaging. Use
5973 <b>`soapcpp2 -s`</b> option <b>`-s`</b> to hard code `SOAP_XML_STRICT` in the
5974 generated serializers. Not recommended with SOAP 1.1/1.2 encoding style
5975 messaging.
5976
5977 - `SOAP_XML_INDENT`: produces indented XML.
5978
5979 - `SOAP_XML_CANONICAL`: c14n canonocalization, removes unused `xmlns` bindings
5980 and adds them to appropriate places by applying c14n normalization rules.
5981 Should not be used together with SOAP 1.1/1.2 encoding style messaging.
5982
5983 - `SOAP_XML_TREE`: write tree XML without id-ref, while pruning data structure
5984 cycles to prevent nontermination of the serializer for cyclic structures.
5985
5986 - `SOAP_XML_GRAPH`: write graph (digraph and cyclic graphs with shared pointers
5987 to objects) using id-ref attributes. That is, XML with SOAP multi-ref
5988 encoded id-ref elements. This is a structure-preserving serialization format,
5989 because co-referenced data and also cyclic relations are accurately represented.
5990
5991 - `SOAP_XML_DEFAULTNS`: uses xmlns default namespace declarations, assuming
5992 that the schema attribute form is "qualified" by default (be warned if it is
5993 not, since attributes in the null namespace will get bound to namespaces!).
5994
5995 - `SOAP_XML_NIL`: emit empty element with <i>`xsi:nil`</i> for all NULL pointers
5996 serialized.
5997
5998 - `SOAP_XML_IGNORENS`: the XML parser ignores XML namespaces, i.e. element and
5999 attribute tag names match independent of their namespace.
6000
6001 - `SOAP_XML_NOTYPE`: removes all <i>`xsi:type`</i> attribuation. This option is usually
6002 not needed unless the receiver rejects all <i>`xsi:type`</i> attributes. This option
6003 may affect the quality of the deserializer, which relies on <i>`xsi:type`</i>
6004 attributes to distinguish base class instances from derived class instances
6005 transported in the XML payloads.
6006
6007 - `SOAP_IO_CHUNK`: to enable HTTP chunked transfers.
6008
6009 - `SOAP_IO_STORE`: full buffering of outbound messages.
6010
6011 - `SOAP_ENC_ZLIB`: compress messages, requires compiling with option <b>`-DWITH_GZIP`</b> and
6012 linking with zlib using option <b>`-lz`</b>.
6013
6014 - `SOAP_ENC_MIME`: enable MIME attachments, see
6015 [DIME/MIME/MTOM attachment binary types](#toxsd10-3).
6016
6017 - `SOAP_ENC_MTOM`: enable MTOM attachments, see
6018 [DIME/MIME/MTOM attachment binary types](#toxsd10-3).
6019
6020 @note C++ Web service proxy and service classes have their own `soap` context, either
6021 as a base class (with <b>`soapcpp2 -i`</b> option <b>`-i`</b>) or as a pointer member `soap` that points to
6022 a context (with <b>`soapcpp2 -j`</b> option <b>`-j`</b>). These contexts are allocated when the proxy or
6023 service is instantiated with context flags that are passed to the constructor.
6024
6025 🔝 [Back to table of contents](#)
6026
6027 Context parameter settings {#params}
6028 ==========================
6029
6030 After allocation and initializtion of a `soap` context, several context
6031 parameters can be set (some parameters may require 2.8.31 or greater):
6032
6033 - `unsigned int soap::maxlevel` is the maximum XML nesting depth levels that
6034 the parser permits. Default initialized to `SOAP_MAXLEVEL` (10000), which is
6035 a redefinable macro in <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxlevel` to a
6036 lower value to restrict XML parsing nesting depth.
6037
6038 - `long soap::maxlength` is the maximum string content length if not already
6039 constrained by an XML schema validation `maxLength` constraint. Zero means
6040 unlimited string lengths are permitted (unless restricted by XML schema
6041 `maxLength`). Default initialized to `SOAP_MAXLENGTH` (0), which is a
6042 redefinable macro in <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxlength` to a
6043 positive value to restrict the number of (wide) characters in strings parsed,
6044 restrict hexBinary byte length, and restrict base64Binary byte length.
6045
6046 - `size_t soap::maxoccurs` is the maximum number of array or container elements
6047 permitted by the parser. Must be greater than zero (0). Default initialized
6048 to `SOAP_MAXOCCURS` (100000), which is a redefinable macro in
6049 <i>`gsoap/stdsoap2.h`</i>. Set `soap::maxoccurs` to a positive value to
6050 restrict the number of array and container elements that can be parsed.
6051
6052 - `soap::version` is the SOAP version used, with 0 for non-SOAP, 1 for SOAP1.1,
6053 and 2 for SOAP1.2. This value is normally set by web service operations, and
6054 is otherwise 0 (non-SOAP). Use `soap_set_version(struct soap*, short)` to
6055 set the value. This controls XML namespaces and SOAP id-ref serialization
6056 when applicable with an encodingStyle (see below).
6057
6058 - `const char *soap::encodingStyle` is a string that is used with SOAP
6059 encoding, normally NULL for non-SOAP XML. Set this string to "" (empty
6060 string) to enable SOAP encoding style, which supports id-ref graph
6061 serialization (see also the `SOAP_XML_GRAPH` [context flag](#flags)).
6062
6063 - `int soap::recvfd` is the file descriptor to read and parse source data from.
6064 Default initialized to 0 (stdin). See also [input and output](#io).
6065
6066 - `int soap::sendfd` is the file descriptor to write data to. Default
6067 initialized to 1 (stdout). See also [input and output](#io).
6068
6069 - `const char *is` for C: string to read and parse source data from, overriding
6070 the `recvfd` source. Normally NULL. This value must be reset to NULL or
6071 the parser will continue to read from this string content until the NUL
6072 character. See also [input and output](#io).
6073
6074 - `std::istream *is` for C++: an input stream to read and parse source data
6075 from, overriding the `recvfd` source. Normally NULL. This value must be
6076 reset to NULL or the parser will continue to read from this stream until EOF.
6077 See also [input and output](#io).
6078
6079 - `const char **os` for C: points to a string (a `const char *`) that will be
6080 set to point to the string output. Normally NULL. This value must be reset
6081 to NULL or the next output will result in reassigning the pointer to point to
6082 the next string that is output. The strings are automatically deallocated by
6083 `soap_end(soap)`. See also [input and output](#io).
6084
6085 - `std::ostream *os` for C++: an output stream to write output to. Normally
6086 NULL. This value must be reste to NULL or the next output will be send to
6087 this stream. See also [input and output](#io).
6088
6089 🔝 [Back to table of contents](#)
6090
6091 Error handling and reporting {#errors}
6092 ============================
6093
6094 The gSOAP API functions return `SOAP_OK` (zero) or a non-zero error code. The
6095 error code is stored in `int soap::error` of the current `soap` context.
6096 Error messages can be displayed with:
6097
6098 - `void soap_stream_fault(struct soap*, std::ostream &os)` for C++ only, prints
6099 the error message to an output stream.
6100
6101 - `void soap_print_fault(struct soap*, FILE *fd)` prints the error message to a
6102 FILE descriptor.
6103
6104 - `void soap_sprint_fault(struct soap*, char *buf, size_t len)` saves the error
6105 message to a fixed-size buffer allocated with a maximum length.
6106
6107 - `void soap_print_fault_location(struct soap*, FILE *fd)` prints the location
6108 and part of the XML where the parser encountered an error.
6109
6110 C++ exceptions are never raised by the engine or serializers, even when data is
6111 allocated.
6112
6113 A `SOAP_EOM` error code is returned when memory was exhausted during
6114 processing of input and/or output of data.
6115
6116 An EOF (`SOAP_EOF` or -1) error code is returned when the parser has hit EOF
6117 but expected more input, or when socket communications timed out. In addition
6118 to the `SOAP_EOF` error, the `int soap::errnum` of the `soap` context is
6119 set to the `errno` value of the operation that failed. For timeouts, the
6120 `soap::ernum` value is always 0 instead of an `errno` error code.
6121
6122 Use `soap_xml_error_check(soap->error)` to check for XML errors. This returns
6123 true (non-zero) when a parsing and validation error has occurred.
6124
6125 For example:
6126
6127 ~~~{.cpp}
6128 #include <sstream>
6129
6130 struct soap *soap = soap_new1(SOAP_XML_INDENT | SOAP_XML_STRICT | SOAP_XML_TREE);
6131 struct ns__record person;
6132 std::stringstream ss;
6133 ss.str("..."); // XML to parse
6134 soap->is = &ss;
6135 if (soap_read__ns__record(soap, &person))
6136 {
6137 if (soap_xml_error_check(soap->error))
6138 std::cerr << "XML parsing error!" << std::endl;
6139 else
6140 soap_stream_fault(soap, std::cerr);
6141 }
6142 else
6143 {
6144 ... // all OK, use person record
6145 }
6146 soap_destroy(soap); // delete objects
6147 soap_end(soap); // delete other data and temp data
6148 soap_free(soap); // free context
6149 ~~~
6150
6151 When deploying your application on UNIX and Linux systems, UNIX signal handlers
6152 should be added to your code handle signals, in particular `SIGPIPE`:
6153
6154 ~~~{.cpp}
6155 signal(SIGPIPE, sigpipe_handler);
6156 ~~~
6157
6158 where the `sigpipe_handler` is a function:
6159
6160 ~~~{.cpp}
6161 void sigpipe_handler(int x) { }
6162 ~~~
6163
6164 Other UNIX signals may have to be handled as well.
6165
6166 The engine is designed for easy memory cleanup after being interrupted. Use
6167 `soap_destroy(soap)` and `soap_end(soap)`, after which the `soap` context can
6168 be reused.
6169
6170 🔝 [Back to table of contents](#)
6171
6172 Features and limitations {#features}
6173 ========================
6174
6175 In general, to use the generated code:
6176
6177 - Make sure to `#include "soapH.h"` in your code and also define a namespace
6178 table or `#include "ns.nsmap"` with the generated table, where `ns` is the
6179 namespace prefix for services.
6180
6181 - Use <b>`soapcpp2 -j`</b> option <b>`-j`</b> (C++ only) to generate C++ proxy and service objects.
6182 The auto-generated files include documented inferfaces. Compile with
6183 <i>`soapC.cpp`</i> and link with <b>`-lgsoap++`</b>, or alternatively compile
6184 <i>`gsoap/stdsoap2.cpp`</i>.
6185
6186 - Without <b>`soapcpp2 -j`</b> option <b>`-j`</b>: client-side uses the auto-generated
6187 <i>`soapClient.cpp`</i> and <i>`soapC.cpp`</i> (or C versions of those).
6188 Compile and link with <b>`-lgsoap++`</b> (<b>`-lgsoap`</b> for C), or
6189 alternatively compile <i>`gsoap/stdsoap2.cpp`</i> (<i>`gsoap/stdsoap2.c`</i>
6190 for C).
6191
6192 - Without <b>`soapcpp2 -j`</b> option <b>`-j`</b>: server-side uses the
6193 auto-generated <i>`soapServer.cpp`</i> and <i>`soapC.cpp`</i> (or C versions
6194 of those). Compile and link with <b>`-lgsoap++`</b> (<b>`-lgsoap`</b> for
6195 C), or alternatively compile <i>`gsoap/stdsoap2.cpp`</i> (<i>`stdsoap2.c`</i>
6196 for C).
6197
6198 - Use `soap_new()` or `soap_new1(int flags)` to allocate and initialize a
6199 heap-allocated `soap` context with or without flags. Delete this `soap` context with
6200 `soap_free(struct soap*)`, but only after `soap_destroy(struct soap*)` and
6201 `soap_end(struct soap*)`.
6202
6203 - Use `soap_init(struct *soap)` or `soap_init1(struct soap*, int flags)` to
6204 initialize a stack-allocated `soap` context with or without flags. End the use of
6205 this context with `soap_done(struct soap*)`, but only after
6206 `soap_destroy(struct soap*)` and `soap_end(struct soap*)`.
6207
6208 Additional notes with respect to the wsdl2h and soapcpp2 tools:
6209
6210 - Nested classes, structs, and unions in a interface header file are unnested
6211 by soapcpp2.
6212
6213 - Use `#import "file.h"` instead of `#include` to import other header files in
6214 a interface header file for soapcpp2. The `#include`, `#define`, and
6215 `#pragma` are accepted by soapcpp2, but are moved to the very start of the
6216 generated code for the C/C++ compiler to include before all generated
6217 definitions. Often it is useful to add an `#include` with a
6218 [volatile type](#toxsd9-2) that includes the actual type declaration, and to
6219 ensure transient types are declared when these are used in a data binding
6220 interface declared in a interface header file for soapcpp2.
6221
6222 - To remove any SOAP-specific bindings, use <b>`soapcpp2 -0`</b> option <b>`-0`</b>.
6223
6224 - A interface header file for soapcpp2 should not include any code statements,
6225 only data type declarations. This includes constructor initialization lists
6226 that are not permitted. Use member initializations instead.
6227
6228 - C++ namespaces are supported. Use <b>`wsdl2h -qname`</b> option
6229 <b>`-qname`</b> to add C++ namespace `name`. Or add a `namespace name { ... }`
6230 to the header file, but the `{ ... }` must cover the entire
6231 header file content from begin to end.
6232
6233 - Optional XML DOM support can be used to store mixed content or literal XML
6234 content. Otherwise, mixed content may be lost. Use <b>`wsdl2h -d`</b>
6235 option <b>`-d`</b> for XML DOM support and compile and link with
6236 <i>`gsoap/dom.c`</i> or <i>`gsoap/dom.cpp`</i>. For details,
6237 see [XML DOM and XPath](http://www.genivia.com/doc/dom/html).
6238
6239 🔝 [Back to table of contents](#)
6240
6241 Removing SOAP namespaces from XML payloads {#nsmap}
6242 ==========================================
6243
6244 The soapcpp2 tool generates a <i>`.nsmap`</i> file that includes two bindings for SOAP
6245 namespaces. We can remove all SOAP namespaces (and SOAP processing logic) with
6246 <b>`soapcpp2 -0`</b> option <b>`-0`</b> or by simply setting the two entries to NULL:
6247
6248 ~~~{.cpp}
6249 struct Namespace namespaces[] =
6250 {
6251 {"SOAP-ENV", NULL, NULL, NULL},
6252 {"SOAP-ENC", NULL, NULL, NULL},
6253 ...
6254 };
6255 ~~~
6256
6257 Once the <i>`.nsmap`</i> is generated, you can copy-paste the content into your
6258 project code. However, if we rerun wsdl2h on updated WSDL/XSD files or
6259 <i>`typemap.dat`</i> declarations then we need to use the updated table.
6260
6261 In cases that no XML namespaces are used at all, for example with
6262 [XML-RPC](http://www.genivia.com/doc/xml-rpc-json/html), you may use an empty
6263 namespace table:
6264
6265 ~~~{.cpp}
6266 struct Namespace namespaces[] = {{NULL,NULL,NULL,NULL}};
6267 ~~~
6268
6269 However, beware that any built-in xsi attributes that are rendered will lack
6270 the proper namespace binding. At least we suggest to use `SOAP_XML_NOTYPE` for
6271 this reason.
6272
6273 🔝 [Back to table of contents](#)
6274
6275 Examples {#examples}
6276 ========
6277
6278 Select the project files below to peruse the source code examples.
6279
6280 🔝 [Back to table of contents](#)
6281
6282 Source files
6283 ------------
6284
6285 - <i>`address.xsd`</i> Address book schema
6286 - <i>`address.cpp`</i> Address book app (reads/writes address.xml file)
6287 - <i>`addresstypemap.dat`</i> Schema namespace prefix name preference for wsdl2h
6288 - <i>`graph.h`</i> Graph data binding (tree, digraph, cyclic graph)
6289 - <i>`graph.cpp`</i> Test graph serialization as tree, digraph, and cyclic
6290
6291 🔝 [Back to table of contents](#)
6292
6293 Generated files
6294 ---------------
6295
6296 - <i>`address.h`</i> data binding interface generated from address.xsd
6297 - <i>`addressStub.h`</i> C++ data binding definitions
6298 - <i>`addressH.h`</i> Serializers
6299 - <i>`addressC.cpp`</i> Serializers
6300 - <i>`address.xml`</i> Address book data generated by address app
6301 - <i>`graphStub.h`</i> C++ data binding definitions
6302 - <i>`graphH.h`</i> Serializers
6303 - <i>`graphC.cpp`</i> Serializers
6304 - <i>`g.xsd`</i> XSD schema with <i>`g:Graph`</i> complexType
6305 - <i>`g.nsmap`</i> xmlns bindings namespace mapping table
6306
6307 🔝 [Back to table of contents](#)
6308
6309 Build steps
6310 -----------
6311
6312 Building the AddressBook example:
6313
6314 wsdl2h -g -taddresstypemap.dat address.xsd
6315 soapcpp2 -0 -C -S -paddress -I../../import address.h
6316 c++ -I../.. address.cpp addressC.cpp -o address -lgsoap++
6317
6318 Using <b>`wsdl2h -g -taddresstypemap.dat`</b> option <b>`-g`</b> produces
6319 bindings for global (root) elements in addition to types and option
6320 <b>`-taddresstypemap.dat`</b> specifies a mapping file, see further below.
6321
6322 In this case the root element <i>`a:address-book`</i> is bound to `_a__address_book`.
6323 The complexType <i>`a:address`</i> is bound to class `a__address`, which is also the
6324 type of `_a__address_book`. This option is not required, but allows you to use
6325 global element tag names when referring to their serializers, instead of their
6326 type name. Using <b>`soapcpp2 -0 -C -S -paddress`</b> option <b>`-0`</b> removes the
6327 SOAP protocol and the combination of the two options <b>`-C`</b> and
6328 <b>`-S`</b> removes client and server code generation (using option <b>`-C`</b>
6329 alone generates client code and using option <b>`-S`</b> alone generates server
6330 code). Option <b>`-paddress`</b> renames the output <i>`soap`</i>-prefixed files to
6331 <i>`address`</i>-prefixed files.
6332
6333 See the <i>`address.cpp`</i> implementation and [related pages](pages.html).
6334
6335 The <i>`addresstypemap.dat`</i> file specifies the XML namespace prefix for the
6336 bindings:
6337
6338 # Bind the address book schema namespace to prefix 'a'
6339
6340 a = "urn:address-book-example"
6341
6342 # By default the xsd:dateTime schema type is translated to time_t
6343 # To map xsd:dateTime to struct tm, enable the following line:
6344
6345 # xsd__dateTime = #import "../../custom/struct_tm.h"
6346
6347 # ... and compile/link with custom/struct_tm.c
6348
6349 The DOB field is a <i>`xsd:dateTime`</i>, which is bound to `time_t` by default. To
6350 change this to `struct tm`, enable the import of the `xsd__dateTime` custom
6351 serializer by uncommenting the definition of `xsd__dateTime` in
6352 <i>`addresstypemap.dat`</i>. Then change `soap_dateTime2s` to `soap_xsd__dateTime2s`
6353 in the code.
6354
6355 Building the graph serialization example:
6356
6357 soapcpp2 -C -S -pgraph -I../../import graph.h
6358 c++ -I../.. graph.cpp graphC.cpp -o graph -lgsoap++
6359
6360 To compile without using the <b>`-lgsoap++`</b> library: simply compile
6361 <i>`stdsoap2.cpp`</i> together with the above.
6362
6363 🔝 [Back to table of contents](#)
6364
6365 Usage
6366 -----
6367
6368 To execute the AddressBook example:
6369
6370 ./address
6371
6372 To execute the Graph serialization example:
6373
6374 ./graph
6375