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Validation Functions

This module contains functions to perform validations against DTDs, XML Schema and Relax NG. The documentation further describes how to use Schematron validation with BaseX.

Conventions

All functions and errors in this module are assigned to the http://basex.org/modules/validate namespace, which is statically bound to the validate prefix.

DTD Validation

Checks whether an XML document validates against a DTD. The input document can be specified as:

  • xs:string, representing a URI (relative URIs will always be resolved against the static base URI of the query),
  • xs:string, representing the resource in its string representation, or
  • node(), representing the resource itself.

If no DTD is supplied in a function, the XML document is expected to contain an embedded DTD doctype declaration.

validate:dtd

Signature
validate:dtd(
  $input   as item(),
  $schema  as xs:string?  := ()
) as empty-sequence()
SummaryValidates the XML $input document against a $schema and returns an empty sequence or an error.
Errors
errorThe document cannot be validated against the specified schema.
initThe validation cannot be started.
not-foundNo validator is available.
Examples
validate:dtd('doc.xml', 'doc.dtd')
Validates the document doc.xml against the specified DTD file doc.dtd.
try {
  let $doc := <invalid/>
  let $schema := '<!ELEMENT root (#PCDATA)>'
  return validate:dtd($doc, $schema)
} catch validate:error {
  'DTD Validation failed.'
}
Validates an invalid document against a DTD, which is specified as string.

validate:dtd-info

Signature
validate:dtd-info(
  $input   as item(),
  $schema  as xs:string?  := ()
) as xs:string*
SummaryValidates the XML $input document against a $schema and returns warnings, errors and fatal errors in a string sequence.
Errors
initThe validation cannot be started.
not-foundNo validator is available.
Examples
validate:dtd-info(<invalid/>, '<!ELEMENT root (#PCDATA)>')
Returns: 2:11: Element type "invalid" must be declared.

validate:dtd-report

Signature
validate:dtd-report(
  $input   as item(),
  $schema  as xs:string?  := ()
) as element(report)
SummaryValidates the XML $input document against a $schema and returns warnings, errors and fatal errors as XML.
Errors
initThe validation cannot be started.
not-foundNo validator is available.
Examples
validate:dtd-report(<invalid/>, '<!ELEMENT root (#PCDATA)>')
The result:
<report>
  <status>invalid</status>
  <message level="Error" line="2" column="11">
    Element type "invalid" must be declared.</message

</report>

XML Schema Validation

Checks whether an XML document validates against an XML Schema. The input document and the schema can be specified as:

  • xs:string, containing the path to the resource,
  • xs:string, containing the resource in its string representation, or
  • node(), containing the resource itself.

If no schema is given, the input is expected to contain an xsi:(noNamespace)schemaLocation attribute, as defined in W3C XML Schema.

Different XML Schema processors are supported:

  • By default, the Java implementation of XML Schema 1.0 is used (it is based on an old version of Apache Xerces).
  • The latest version of Xerces2 provides implementations of XML Schema 1.0 and 1.1. The processor will be applied if you download one of the binary distributions and copy the following libraries to the lib/custom directory of the full distribution of BaseX:
    • org.eclipse.wst.xml.xpath2.processor_1.2.0.jar
    • cupv10k-runtime.jar
    • xercesImpl.jar
    • xml-apis.jar
  • Saxon Enterprise Edition will be used if you download the ZIP release and if you copy saxon9ee.jar and a valid license key to the classpath.

validate:xsd

Updated: Caching feature added.

Signature
validate:xsd(
  $input    as item(),
  $schema   as item()?  := (),
  $options  as map(*)?  := {}
) as empty-sequence()
SummaryValidates the XML $input document against a $schema. The following $options are available:
optiondefaultdescription
cachefalse() Generated schemas are cached and reused.
*other* Handled as features and passed on to the validator.
Errors
errorThe document cannot be validated against the specified schema.
initThe validation cannot be started.
not-foundNo validator is available.
Examples
let $doc := <simple:root xmlns:simple='http://basex.org/simple'/>
let $schema :=
  <xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema'
      targetNamespace='http://basex.org/simple'>
    <xs:element name='root'/>
  </xs:schema>
return validate:xsd($doc, $schema)
Pass on document and schema as nodes.
for $city in db:get('cities')
return validate:xsd($city, 'city.xsd',
  { 'http://javax.xml.XMLConstants/feature/secure-processing': true() }
)
Validate all documents of a database against the specified schema, using the supplied feature.

validate:xsd-info

Signature
validate:xsd-info(
  $input    as item(),
  $schema   as item()?  := (),
  $options  as map(*)?  := {}
) as xs:string*
SummaryValidates the XML $input document against a $schema and returns warnings, errors and fatal errors in a string sequence. See validate:xsd for more information of the $options parameter.
Errors
initThe validation cannot be started.
not-foundNo validator is available.

validate:xsd-report

Signature
validate:xsd-report(
  $input    as item(),
  $schema   as xs:string?  := (),
  $options  as map(*)      := {}
) as element(report)
SummaryValidates the XML $input document against a $schema and returns warnings, errors and fatal errors as XML. See validate:xsd for more information of the $options parameter.
Errors
initThe validation cannot be started.
not-foundNo validator is available.

validate:xsd-init

Signature
validate:xsd-init() as empty-sequence()
SummaryDiscards the cached XSD schemas.

validate:xsd-processor

Signature
validate:xsd-processor() as xs:string
SummaryReturns the name of the applied XSD processor.

validate:xsd-version

Signature
validate:xsd-version() as xs:string
SummaryReturns the supported version of XSD Schema.

Relax NG Validation

Checks whether an XML document validates against a RelaxNG schema. The input document and the schema can be specified as:

  • xs:string, containing the path to the resource,
  • xs:string, containing the resource in its string representation, or
  • node(), containing the resource itself.

Relax NG validation will be available if Jing exists in the classpath. The latest version, jing-20091111.jar, is included in the full distributions of BaseX. As Jing additionally supports NVDL validation, you can also use the functions to validate the input against NVDL schemas.

validate:rng

Signature
validate:rng(
  $input    as item(),
  $schema   as item(),
  $compact  as xs:boolean?  := {}
) as empty-sequence()
SummaryValidates the XML $input document against a $schema, using the XML or $compact notation.
Errors
errorThe document cannot be validated against the specified schema.
initThe validation cannot be started.
not-foundNo validator is available.
Examples
validate:rng('doc.xml', 'doc.rng')
Validates the document doc.xml against the specified schema doc.rng.

validate:rng-info

Signature
validate:rng-info(
  $input    as item(),
  $schema   as item(),
  $compact  as xs:boolean?  := {}
) as xs:string*
SummaryValidates the XML $input document against a $schema, using the XML or $compact notation, and returns warnings, errors and fatal errors in a string sequence.
Errors
initThe validation cannot be started.
not-foundNo validator is available.

validate:rng-report

Signature
validate:rng-report(
  $input    as item(),
  $schema   as xs:string,
  $compact  as xs:boolean?  := {}
) as element(report)
SummaryValidates the XML $input document against a $schema, using the XML or $compact notation, and returns warnings, errors and fatal errors as XML.
Errors
initThe validation cannot be started.
not-foundNo validator is available.

Schematron Validation

If you want to use Schematron for validating documents, install Vincent Lizzi’s excellent Schematron XQuery Module for BaseX:

repo:install(
  'https://github.com/Schematron/schematron-basex/raw/master/dist/schematron-basex-1.2.xar'
)

The following query illustrates how documents are validated. It is directly taken from the GitHub project:

import module namespace sch = "http://github.com/Schematron/schematron-basex";

let $sch := sch:compile(doc('rules.sch'))
let $svrl := sch:validate(doc('document.xml'), $sch)
return (
  sch:is-valid($svrl),
  for $message in sch:messages($svrl)
  return sch:message-level($message) || ': ' || sch:message-description($message)
)

Errors

CodeDescription
errorThe document cannot be validated against the specified schema.
initThe validation cannot be started.
not-foundNo validator is available.

Changelog

Version 11.0Version 9.2Version 9.0
  • Updated: error codes updated; errors now use the module namespace
Version 8.5
  • Updated: Relative URIs will always be resolved against the static base URI of the query
Version 8.3Version 7.6Version 7.3
  • Added: New module added.

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