Validating XML 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 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 mediator.

Syntax

XML

* + mediator+ ]]>

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 Name	Description
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.
Enable Cache Schema	This check box is enabled by default to ensure that schemas retrieved from the registry for one service/REST API are cached for future use. Using Templates? Be sure to disable this check box if you are using the Validate mediator inside a . Since multiple proxy services/REST APIs will be accessing one template, schemas that are cached for one service can interrupt another service that uses the same template.
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.

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 Name	Description
Feature Name	The name of the feature.
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.

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 creates a SOAP fault to be sent back to the party which sent the message.

XML


                
                
         

]]>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.
xml
	
]]>The Validate mediator can be configured as follows.
xml
	
	
	
		
			
			
		
	
]]>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  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.
jsonValidating JSON messagesThe  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  or    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  mediator.
Syntax 

XML
   +
   
      mediator+
   
]]>
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 Name Description
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)"
Enable Cache Schema This check box is enabled by default to ensure that schemas retrieved from the registry for one service/REST API are cached for future use.
Using Templates?Be sure to disable this check box if you are using the Validate mediator inside a . Since multiple proxy services/REST APIs will be accessing one template, schemas that are cached for one service can interrupt another service that uses the same template.
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.
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.javaBLOCKExample 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  creates a fault to be sent back to the party, which sends the message.
java
    
    
        
            {"Error":"$1",
            "Error Details " : " $2"       }
            
                
                
            
        
        
        
    

]]>An example for a valid JSON payload request is given below.
javaWhen you send an invalid JSON, the following response will appear.
javaExample 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.
xml
    
    
        
            {"Error":"$1",
            "Error Details " : " $2"       }
            
                
                
            
        
        
        
    
]]>
An example for a valid JSON request payload is given below.
java
When you send an invalid JSON, the following response will appear.
java

Validate Mediator

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