URN schema validation

Each Magento module can contain XSD files for XML validation.

Magento uses Uniform Resource Names (URNs) to reference XML schema declarations.

Magento supported URNs begin with urn:magento. Magento supports two XSD reference types:

  • Module XSD
  • Framework XSD

You cannot change the XSD for any XML files provided with the Magento application.

Module XSD

The syntax for the module XSD is a colon separated declaration. An example follows:

urn:magento:module:Magento_Flow:flows/content.xsd

where

  • urn:magento is the URN identifier
  • module is the reference type identifier
  • Magento_Flow is the name of the module. This must be exactly the same as the module specified by ComponentRegistrar in the registration.php file.
  • flows/content.xsd is the relative path to the module’s directory.

Framework XSD

The syntax for the framework XSD is a colon separated declaration. An example follows:

urn:magento:framework:Api/etc/extension_attributes.xsd

where

  • urn:magento is the URN identifier
  • framework is the reference type identifier. You can also add additional framework libraries as separate components with framework-<sub-name>
  • Api/etc/extension_attributes.xsd is the relative path to the framework’s directory.

Referencing a XSD from another XSD

Use URN notation to reference schema from inside a XSD document:

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<xs:redefine schemaLocation="urn:magento:framework:Config/etc/view.xsd">

The URN resolution is invoked automatically by the libxml engine. Register the URN resolver by using libxml_set_external_entity_loader:

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libxml_set_external_entity_loader(['Magento\Framework\Config\Dom\UrnResolver', 'registerEntityLoader']);

The relative path to other XSDs cannot be used from inside the XSD file, because the entity loader fails to resolve the relative path.

Next step

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