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The Valiade Mediator is used for schema validation of messages.

The portion of the message that needs to be validated is chosen by evaluating the XPath expression. Then this message is validated against the schema specified. Users can specify a sequence to be executed in case of a validation failure. This mediator provides an extension point by providing properties to configure the underline validation engineThe Validate Mediator validates XML messages against a specified schema. You can specify an XPath to extract and validate a specific part of the message. Otherwise, the mediator validates the first child of the SOAP body of the current message.

Tip
A Fault Mediator should be added as a child to the Validate mediator in order specify the fault sequence to be followed if the validation fails.

Info
The Validate mediator is a content aware mediator.

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Code Block

	XML
	XML

<validate [source="xpath"]>
   <property name="validation-feature-id" value="true|false"/>*
   <schema key="string"/>+
   <on-fail>
      mediator+
   </on-fail>
</validate>

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UI Configuration

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The Validate Mediator validates the result of the evaluation of the source XPath expression, against the schema specified. If the source attribute is not specified, the validation is performed against the first child of the SOAP body of the current message. If the validation fails, the on-fail sequence of mediators is executed. Properties could be used to turn some of the features of the validator on/off.

UI Configuration

Image Removedmediator configuration can be divided into the following sections.

Schema keys defined for Validate Mediator

This section is used to specify the key to access the main schema based on which the validation is carried out, as well as to specify the XML which needs to be validated. The parameters available in this section are as follows.

Parameter Name	Description
Schema keys defined for Validate MediatorThis parameter is used to specify the table	The key for the schema location. It can be specified using one of the following methods. Enter a static key if If the key is a static value.Enter an expression to calculate the value if , select Static Key from the list and enter a static key in the data field. This value should be pre-defined and saved as a resource in the Registry. Click either Configuration Registry or Governance Registry as relevant to select the required key from the resource tree. If the key is a dynamic value.

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, Select Dynamic Key from the list and enter an expression to calculate the value in the data field.

Click Add Key to add a new schema key. Click Delete in the relevant row to delete a schema key.

Info

title	Tip

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To add a new Schema Key, use the "Add New Schema Key" link.

You can click NameSpaces to add namespaces if you are providing an expression. Then the Namespace Editor panel would appear where you can provide any number of namespace prefixes and URLs used in the XPath expression.

Source

The XPath expression to extract the XML that needs to be validated. The Validate mediator validates the evaluation of this expression against the schema specified in the Schema keys defined for Validate Mediator table. If this is not specified, the validation is performed against the first child of the SOAP body of the current message.

Info

title	Tip

You can click

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NameSpaces to add namespaces if you are providing an expression.

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Then the Namespace Editor panel would appear where you can provide any number of namespace prefixes and

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URLs used in the XPath expression.

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Features Defined for Validator Mediator

This section is used to specify which features of the Validate mediator should be enabled and which should be disabled. The parameters available in this section are as follows.

Info
Only the FEATURE_SECURE_PROCESSING feature is currently supported by the validator.

Parameter Name	Description
Feature Name

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The name of the feature.

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title	Note

Value	Click True to enable the feature, or click False to disable the feature.
Action	Click Delete in the relevant row to delete a feature.

Resources of the Validate Mediator

A resource in the Validate mediator configuration enables you to import a schema referenced within another schema. In order to access such a schema via a resource, the parent schema should be saved as a resource in the registry. The parameters available in this section are as follows.

Parameter Name	Description
Location	The location of the schema to be imported. The value entered here should be equal to the value of the `schema location` attribute within the relevant `<xsd:import>` element in the parent schema.
Key	The key to access the parent schema saved in the registry. Click either Configuration Registry or Governance Registry as relevant to select the key from the resource tree.

Info

title	Note

You can also configure the Mediator using XML. Click on "switch to source view" in the "Mediator" window.

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Example

Example 1 - Basic configuration

In this example, the required schema for validating messages going through the validate mediator is given as a registry key, schema\sample.xsd. No source attribute is specified, and therefore the schema will be used to validate the first child of the SOAP body. The mediation logic to follow if the validation fails is defined within the on-fail element. In this example, the Fault Mediator creates a SOAP fault to be sent back to the party which sent the message.

Code Block

	XML
	XML

<validate>
    <schema key="schema\sample.xsd"/>
         <on-fail>
                <makefault>
                    <code value="tns:Receiver"
                            xmlns:tns="http://www.w3.org/2003/05/soap-envelope"/>
                    <reason value="Invalid Request!!!"/>
                </makefault>
                <property name="RESPONSE" value="true"/>
                <header name="To" expression="get-property('ReplyTo')"/>
         </on-fail>
</validate>

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Example 2 - Validate mediator with resources

In this example, the following schema named 08MockServiceSchema is saved in the Registry. This schema is located in MockDataTypes.xsd. A reference is made within this schema to another schema named 08SOAPFaults which is located in SOAPFaults.xsd.

Code Block

language	xml

<xsd:import namespace= "http://samples.synapse.com/08MockServiceSchema" schemalocation= "MockDataTypes.xsd">
	<xsd:import namespace= "http://samples.synapse.com/08SOAPFaults" schemalocation= "../Common/SOAPFaults.xsd">
</xsd:import>

The Validate mediator can be configured as follows.

Code Block

language	xml

<validate>
	<schema key="MockDataTypes.xsd"/>
	<resource location="../Common/SOAPFaults.xsd" key="conf:custom/schema/SOAPFaults.xsd"/>
	<on-fail>
		<log level="custom">
			<property name="validation failed" value="Validation failed ###"/>
			<property name="error_msg" expression="$ctx:ERROR_MESSAGE"/>
		</log>
	</on-fail>
</validate>

The schema used by the validate mediator is MockDataTypes.xsd. In addition, a resource is used to import the 08 SOAPFaults schema which is referred in the 08MockServiceSchema schema. Note that the value ../Common/SOAPFaults.xsd which is specified as the location for the schema to be imported is the same as the location specified for 08 SOAPFaults schema in the 08MockServiceSchema configuration.

The on-fail sequence of this Validate mediator includes a Log mediator which is added as a child to the Validate mediator. This log mediator uses two properties to generate the error message Validation failed ### when the validation of a message against the schemas specified fails.

Excerpt

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Description of the Validate Mediator in WSO2 ESB.

Versions Compared

Old Version 4

New Version Current

Key

UI Configuration

UI Configuration

Schema keys defined for Validate Mediator

Features Defined for Validator Mediator

Resources of the Validate Mediator

Example

Example 1 - Basic configuration

Example 2 - Validate mediator with resources