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