1Schema(3) User Contributed Perl Documentation Schema(3)
2
6 XML::Validator::Schema - validate XML against a subset of W3C XML
7 Schema
8
10 use XML::SAX::ParserFactory;
11 use XML::Validator::Schema;
12 #
14 # create a new validator object, using foo.xsd
15 #
16 $validator = XML::Validator::Schema->new(file => 'foo.xsd');
17 #
19 # create a SAX parser and assign the validator as a Handler
20 #
21 $parser = XML::SAX::ParserFactory->parser(Handler => $validator);
22 #
24 # validate foo.xml against foo.xsd
25 #
26 eval { $parser->parse_uri('foo.xml') };
27 die "File failed validation: $@" if $@;
28
30 This module allows you to validate XML documents against a W3C XML
31 Schema. This module does not implement the full W3C XML Schema
32 recommendation (http://www.w3.org/XML/Schema), but a useful subset.
33 See the SCHEMA SUPPORT section below.
34 IMPORTANT NOTE: To get line and column numbers in the error messages
36 generated by this module you must install XML::Filter::ExceptionLocator
37 and use XML::SAX::ExpatXS as your SAX parser. This module is much more
38 useful if you can tell where your errors are, so using these modules is
39 highly recommeded!
40
42 • "XML::Validator::Schema->new(file => 'file.xsd', cache => 1)"
43 Call this method to create a new XML::Validator:Schema object. The
45 only required option is "file" which must provide a path to an XML
46 Schema document.
47 Setting the optional "cache" parameter to 1 causes
49 XML::Validator::Schema to keep a copy of the schema parse tree in
50 memory. The tree will be reused on subsequent calls with the same
51 "file" parameter, as long as the mtime on the schema file hasn't
52 changed. This can save a lot of time if you're validating many
53 documents against a single schema.
54 Since XML::Validator::Schema is a SAX filter you will normally pass
56 this object to a SAX parser:
57 $validator = XML::Validator::Schema->new(file => 'foo.xsd');
59 $parser = XML::SAX::ParserFactory->parser(Handler => $validator);
60 Then you can proceed to validate files using the parser:
62 eval { $parser->parse_uri('foo.xml') };
64 die "File failed validation: $@" if $@;
65 Setting the optional "debug" parameter to 1 causes
67 XML::Validator::Schema to output elements and associated attributes
68 while parsing and validating the XML document. This provides useful
69 information on the position where the validation failed (although
70 not at useful as the line and column numbers included when
71 XML::Filter::ExceptiionLocator and XML::SAX::ExpatXS are used).
72
74 I'm writing a piece of software which uses Xerces/C++ (
75 http://xml.apache.org/xerces-c/ ) to validate documents against XML
76 Schema schemas. This works very well, but I'd like to release my
77 project to the world. Requiring users to install Xerces is simply too
78 onerous a requirement; few will have it already and the Xerces
79 installation system leaves much to be desired.
80 On CPAN, the only available XML Schema validator is XML::Schema.
82 Unfortunately, this module isn't ready for use as it lacks the ability
83 to actually parse the XML Schema document format! I looked into
84 enhancing XML::Schema but I must admit that I'm not smart enough to
85 understand the code... One day, when XML::Schema is completed I will
86 replace this module with a wrapper around it.
87 This module represents my attempt to support enough XML Schema syntax
89 to be useful without attempting to tackle the full standard. I'm sure
90 this will mean that it can't be used in all situations, but hopefully
91 that won't prevent it from being used at all.
92
94 Supported Elements
95 The following elements are supported by the XML Schema parser. If you
96 don't see an element or an attribute here then you definitely can't use
97 it in a schema document.
98 You can expect that the schema document parser will produce an error if
100 you include elements which are not supported. However, unsupported
101 attributes may be silently ignored. This should not be misconstrued as
102 a feature and will eventually be fixed.
103 All of these elements must be in the http://www.w3.org/2001/XMLSchema
105 namespace, either using a default namespace or a prefix.
106 <schema>
108 Supported attributes: targetNamespace, elementFormDefault,
110 attributeFormDefault
111 Notes: the only supported values for elementFormDefault and
113 attributeFormDefault are "unqualified." As such, targetNamespace
114 is essentially ignored.
115 <element name="foo">
117 Supported attributes: name, type, minOccurs, maxOccurs, ref
119 <attribute>
121 Supported attributes: name, type, use, ref
123 <sequence>
125 Supported attributes: minOccurs, maxOccurs
127 <choice>
129 Supported attributes: minOccurs, maxOccurs
131 <all>
133 Supported attributes: minOccurs, maxOccurs
135 <complexType>
137 Supported attributes: name
139 <simpleContent>
141 The only supported sub-element is <extension>.
143 <extension>
145 Supported attributes: base
147 Notes: only allowed inside <simpleContent>
149 <simpleType>
151 Supported attributes: name
153 <restriction>
155 Supported attributes: base
157 Notes: only allowed inside <simpleType>
159 <whiteSpace>
161 Supported attributes: value
163 <pattern>
165 Supported attributes: value
167 <enumeration>
169 Supported attributes: value
171 <length>
173 Supported attributes: value
175 <minLength>
177 Supported attributes: value
179 <maxLength>
181 Supported attributes: value
183 <minInclusive>
185 Supported attributes: value
187 <minExclusive>
189 Supported attributes: value
191 <maxInclusive>
193 Supported attributes: value
195 <maxExclusive>
197 Supported attributes: value
199 <totalDigits>
201 Supported attributes: value
203 <fractionDigits>
205 Supported attributes: value
207 <annotation>
209 <documentation>
211 Supported attributes: name
213 <union>
215 Supported attributes: MemberTypes
216 Simple Type Support
218 Supported built-in types are:
219 string
221 normalizedString
223 token
225 NMTOKEN
227 Notes: the spec says NMTOKEN should only be used for attributes,
229 but this rule is not enforced.
230 boolean
232 decimal
234 Notes: the enumeration facet is not supported on decimal or any
236 types derived from decimal.
237 integer
239 int
241 short
243 byte
245 unsignedInt
247 unsignedShort
249 unsignedByte
251 positiveInteger
253 negativeInteger
255 nonPositiveInteger
257 nonNegativeInteger
259 dateTime
261 Notes: Although dateTime correctly validates the lexical format it does not
263 offer comparison facets (min*, max*, enumeration).
264 double
266 Notes: Although double correctly validates the lexical format it
268 does not offer comparison facets (min*, max*, enumeration). Also,
269 minimum and maximum constraints as described in the spec are not
270 checked.
271 float
273 Notes: The restrictions on double support apply to float as well.
275 duration
277 time
279 date
281 gYearMonth
283 gYear
285 gMonthDay
287 gDay
289 gMonth
291 hexBinary
293 base64Binary
295 anyURI
297 QName
299 NOTATION
301 Miscellaneous Details
303 Other known devations from the specification:
304 • Patterns specified in pattern simpleType restrictions are Perl
306 regexes with none of the XML Schema extensions available.
307 • No effort is made to prevent the declaration of facets which
309 "loosen" the restrictions on a type. This is a bug and will be
310 fixed in a future release. Until then types which attempt to
311 loosen restrictions on their base class will behave unpredictably.
312 • No attempt has been made to exclude content models which are
314 ambiguous, as the spec demands. In fact, I don't see any
315 compelling reason to do so, aside from strict compliance to the
316 spec. The content model implementaton uses regular expressions
317 which should be able to handle loads of ambiguity without
318 significant performance problems.
319 • Marking a facet "fixed" has no effect.
321 • SimpleTypes must come after their base types in the schema body.
323 For example, this is ok:
324 <xs:simpleType name="foo">
326 <xs:restriction base="xs:string">
327 <xs:minLength value="10"/>
328 </xs:restriction>
329 </xs:simpleType>
330 <xs:simpleType name="foo_bar">
331 <xs:restriction base="foo">
332 <xs:length value="10"/>
333 </xs:restriction>
334 </xs:simpleType>
335 But this is not:
337 <xs:simpleType name="foo_bar">
339 <xs:restriction base="foo">
340 <xs:length value="10"/>
341 </xs:restriction>
342 </xs:simpleType>
343 <xs:simpleType name="foo">
344 <xs:restriction base="xs:string">
345 <xs:minLength value="10"/>
346 </xs:restriction>
347 </xs:simpleType>
348
350 Here are a few gotchas that you should know about:
351 • No Unicode testing has been performed, although it seems possible
353 that the module will handle Unicode data correctly.
354 • Namespace processing is almost entirely missing from the module.
356 • Little work has been done to ensure that invalid schemas fail
358 gracefully. Until that is done you may want to develop your
359 schemas using a more mature validator (like Xerces or XML Spy)
360 before using them with this module.
361
363 Please use "rt.cpan.org" to report bugs in this module:
364 http://rt.cpan.org
366 Please note that I will delete bugs which merely point out the lack of
368 support for a particular feature of XML Schema. Those are feature
369 requests, and believe me, I know we've got a long way to go.
370
372 This module is supported on the perl-xml mailing-list. Please join the
373 list if you have questions, suggestions or patches:
374 http://listserv.activestate.com/mailman/listinfo/perl-xml
376
378 If you'd like to help develop XML::Validator::Schema you'll want to
379 check out a copy of the CVS tree:
380 http://sourceforge.net/cvs/?group_id=89764
382
384 The following people have contributed bug reports, test cases and/or
385 code:
386 Russell B Cecala (aka Plankton)
388 David Wheeler
389 Toby Long-Leather
390 Mathieu
391 h.bridge@fasol.fujitsu.com
392 michael.jacob@schering.de
393 josef@clubphoto.com
394 adamk@ali.as
395 Jean Flouret
396
398 Sam Tregar <sam@tregar.com>
399
401 Copyright (C) 2002-2003 Sam Tregar
402 This program is free software; you can redistribute it and/or modify it
404 under the same terms as Perl 5 itself.
405
407 This module isn't just an XML Schema validator, it's also a test of the
408 Test Driven Development methodology. I've been writing tests while I
409 develop code for a while now, but TDD goes further by requiring tests
410 to be written before code. One consequence of this is that the module
411 code may seem naive; it really is just enough code to pass the current
412 test suite. If I'm doing it right then there shouldn't be a single
413 line of code that isn't directly related to passing a test. As I add
414 functionality (by way of writing tests) I'll refactor the code a great
415 deal, but I won't add code only to support future development.
416 For more information I recommend "Test Driven Development: By Example"
418 by Kent Beck.
419
421 XML::Schema
422 http://www.w3.org/XML/Schema
424 http://xml.apache.org/xerces-c/
426perl v5.34.0 2021-07-23 Schema(3)