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You can use the Validate mediator to validate XML and JSON messages.

The 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.

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.

The Validate mediator is a content aware mediator.

 


Syntax

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

 


UI Configuration

The mediator 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 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 NameDescription
Schema keys defined for Validate Mediator table

The key for the schema location. It can be specified using one of the following methods.

  • If the key is a static value, 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, 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.

Tip

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.

Tip

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. 

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.

Only the FEATURE_SECURE_PROCESSING feature is currently supported by the validator.

Parameter NameDescription
Feature NameThe name of the feature.
ValueClick True to enable the feature, or click False to disable the feature.
ActionClick 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 NameDescription
LocationThe 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.
KeyThe 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.

Note

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

 


Examples

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.

<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>

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.

<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.

<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.

The Validate mediator validates JSON messages against a specified JSON schema. You can specify a JSONPath to extract and validate a specific part of the message. Otherwise, the mediator validates the complete content of the current message.

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

The Validate mediator is a content aware mediator.

 


Syntax

 

<validate [source="xpath"]>
   <schema key="string"/>+
   <on-fail>
      mediator+
   </on-fail>
</validate>

UI Configuration


The mediator 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 validation is carried out, as well as to specify the JSON message which needs to be validated. The parameters available in this section are as follows.

 

Parameter NameDescription
Schema keys defined for Validate Mediator

The key for the schema location. It can be specified using one of the following methods.

  •   If the key is a static value, 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, 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.

Source

The JSONPath expression to extract the JSON element 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 whole body of the current message.

E.g: json-eval($.msg)"

Note

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

Examples

Following examples use the below sample schema StockQuoteSchema.json file. Add this sample schema file (i.e. StockQuoteSchema.json) to the following Registry path: conf:/schema/StockQuoteSchema.json. For instructions on adding the schema file to the Registry path, see Adding a Resource.

When adding this sample schema file to the Registry, specify the Media Type as application/json.

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "properties": {
    "getQuote": {
      "type": "object",
      "properties": {
        "request": {
          "type": "object",
          "properties": {
            "symbol": {
              "type": "string"
            }
          },
          "required": [
            "symbol"
          ]
        }
      },
      "required": [
        "request"
      ]
    }
  },
  "required": [
    "getQuote"
  ]
}

Example 1 - Basic configuration

In this example, the required schema for validating messages going through the Validate mediator is given as a registry key (i.e. schema\StockQuoteSchema.json). You do not have any source attributes specified. Therefore, the schema will be used to validate the complete JSON body. The mediation logic to follow if the validation fails is defined within the on-fail element. In this example, the PayloadFactory mediator creates a fault to be sent back to the party, which sends the message.

<validate>
    <schema key="conf:/schema/StockQuoteSchema.json"/>
    <on-fail>
        <payloadFactory media-type="json">
            <format>{"Error":$1"}</format>
            <args>
                <arg evaluator="xml" expression="$ctx:ERROR_MESSAGE"/>
            </args>
        </payloadFactory>
        <property name="HTTP_SC" value="500" scope="axis2"/>
        <respond/>
    </on-fail>
</validate>

An example for a valid JSON payload request is given below.

{
   "getQuote": {
      "request": {
         "symbol": "WSO2"
      }
   }
}

 

Example 2 - Validate mediator with source (JSONPath)

In this example, it extracts the message element from the JSON request body and validates only that part of the message against the given schema.
<validate source="json-eval($.msg)">
    <schema key="conf:/schema/StockQuoteSchema.json"/>
    <on-fail>
        <payloadFactory media-type="json">
            <format>{"Error":$1"}</format>
            <args>
                <arg evaluator="xml" expression="$ctx:ERROR_MESSAGE"/>
            </args>
        </payloadFactory>
        <property name="HTTP_SC" value="500" scope="axis2"/>
        <respond/>
    </on-fail>
</validate>
An example for a valid JSON request payload is given below.

 

{
   "msg": {
      "getQuote": {
         "request": {
            "symbol": "WSO2"
         }
      }
   }
}

 


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