Primer: Passing the User Headers

How to pass OSB user headers to and from the backend service in a parallel call.

A split-join service drops all user headers. End of story.

This is because split-join is not really an OSB service, but an implementation of a BPEL engine. It has no idea of OSB-specific concepts such as user headers.

As usual, GenericParallel has a built-in workaround for this limitation.

Passing User Headers to the Backend

To pass user headers with requests via GenericParallel, the caller just needs to include them as attributes of the element. Any attribute that is not GPS’s own, will be passed down to the target service as a user header.

In the example below a user header named DebugId with a value “100500” will be passed to the Profile/RetrieveProfile service.

<typ:GPS xmlns:typ="http://genericparallel/types">
  <typ:Requests>
   <typ:Request DebugId="100500" GPSTarget="Profile/RetrieveProfile">
       <RetrieveProfile>
         <AccountNo>12345678</AccountNo>
       </RetrieveProfile> 
   </typ:Request> 

   ... more requests here ...

  </typ:Requests> 
</typ:GPS>

Passing User Headers from the Backend

If the response contains user headers, they will be provided in the GenericParallel response as well.

The headers will be returned as attributes of the element. In the example below, the response contains the user header DebugActualBackendDb with value “E12”.

<types:GPSResponse xmlns:types="http://genericparallel/types">
  <types:Responses>

    <types:Response GPSIndex="1" GPSBatchIndex="1" DebugActualBackendDB="E12">
    ...
    </types:Response>

    ... more responses here ...

  </types:Responses>
</types:GPSResponse>

If you’d like to learn more, feel free to try GenericParallel.