Adding a Non-Blocking Send Operation

In this example, the Send mediator in a proxy service using the VFS transport is transferring a file to a VFS endpoint.

VFS is a non-blocking transport by default, which means a new thread is spawned for each outgoing message.

Let's create a new policy using the example provided below. Go ahead and create your own content by following the example and save it as a .xml file. Note that the Property mediator added before the Send mediator removes the ClientAPINonBlocking property from the message in order to perform the mediation in a single thread. This is required when the file being transferred is large and you want to avoid out-of-memory failures.

Example

<sequence xmlns="http://ws.apache.org/ns/synapse" name="non-blocking-send">
  <property name="ClientApiNonBlocking"
           value="true"
           scope="axis2"
           action="remove"/>
  <send>
     <endpoint name="FileEpr">
        <address uri="vfs:file:////home/shammi/file-out"/>
     </endpoint>
  </send>
</sequence>

Let's assume that the policy file that you created by considering the example above is addNonBlockingSend.xml. We will next create a policy using this policy file. You can refer to Create a Policy to learn more about how to achieve this. When creating the policy, make sure to only select the Request flow when filling out the general details of the create policy form. Thus created policy can then be attached to the request flow of any API operation (refer Attach Policies for further details).