Discarding an cancelled request

[vicva...@gmail.com]

Hi Guys,

I have a grpc service which does some cpu intensive work.
Before starting the work, I want to ensure that the client hasn't cancelled this aforementioned work.
Rather than checking in every service, I would like to write an interceptor which would check and drop the request if it has been cancelled.

This is what I have come up with but I can't figure out how to drop the request and signal to the client.
Any pointers are much appreciated.

Cheers

public final class CancelledRequestInterceptor implements ServerInterceptor{

@Override
public final <R, S> Server.Listener<R> interceptCall( ServerCall<R,S> call, Metadata meta, ServerCallHandler<R, S> next ){

    boolean isCancelled = Context.current().isCancelled();
    if( isCancelled ){
       //How do I discard the call and signal to the client that it has been discarded
    }else{
       return next.startCall( call, headers );
    }

}

[Eric Anderson]

Just handle the ServerCall directly. Since you don't actually need the listener, you can give a no-op one. If you need to provide additional error information, you can provide it in the Metadata.

if (isCancelled) {

  call.close(Status.SOME_STATUS.withDescription("some description"), new Metadata());

  return new ServerCall.Listener<R>() {};

}

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[vicva...@gmail.com]

Thanks Eric, I will give it a try.