Handling Non-Matching Resources

This example demonstrates how you can define a sequence to be invoked if the Micro Integrator is unable to find a matching resource definition for a specific API invocation. This sequence generates a response indicating an error when no matching resource definition is found.

Synapse configurations

Following is a sample REST API configuration and Sequence configuration that we can used to implement this scenario. See the instructions on how to build and run this example.

<api xmlns="http://ws.apache.org/ns/synapse" name="jaxrs" context="/jaxrs">
   <resource methods="GET" uri-template="/customers/{id}">
      <inSequence>
         <send>
            <endpoint>
               <address uri="http://localhost:8290/jaxrs_basic/services/customers/customerservice"/>
            </endpoint>
         </send>
      </inSequence>
      <outSequence>
         <send/>
      </outSequence>
   </resource>
</api> 
 <sequence xmlns="http://ws.apache.org/ns/synapse" name="_resource_mismatch_handler_">
   <payloadFactory>
      <format>
         <tp:fault xmlns:tp="http://test.com">
            <tp:code>404</tp:code>
            <tp:type>Status report</tp:type>
            <tp:message>Not Found</tp:message>
            <tp:description>The requested resource (/$1) is not available.</tp:description>
         </tp:fault>
      </format>
      <args>
         <arg xmlns:ns="http://org.apache.synapse/xsd" expression="$axis2:REST_URL_POSTFIX"/>
      </args>
   </payloadFactory>
   <property name="RESPONSE" value="true" scope="default"/>
   <property name="NO_ENTITY_BODY" action="remove" scope="axis2"/>
   <property name="HTTP_SC" value="404" scope="axis2"/>
   <header name="To" action="remove"/>
   <send/>
</sequence>

Build and run

Create the artifacts:

  1. Set up WSO2 Integration Studio.
  2. Create an ESB Solution project.
  3. Create the rest api and mediation sequence with the configurations given above.
  4. Deploy the artifacts in your Micro Integrator.

Set up the back-end service:

  1. Download the stockquote_service.jar

  2. Open a terminal, navigate to the location of the downloaded service, and run it (stock quote service) using the following command:

    java -jar stockquote_service.jar

Send an invalid request to the back end as follows:

curl -X GET http://localhost:8290/jaxrs/customers-wrong/123

You will get the following response:

<tp:fault xmlns:tp="http://test.com">
<tp:code>404</tp:code>
<tp:type>Status report</tp:type>
<tp:message>Not Found</tp:message>
<tp:description>The requested resource (//customers-wrong/123) is not available.</tp:description>
</tp:fault>
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