Method createServiceMethod

packages/microservices/server/server-grpc.ts:269–295

* Will return async function which will handle gRPC call * with Rx streams or as a direct call passthrough * * @param methodHandler * @param protoNativeHandler * @param streamType

(
    methodHandler: Function,
    protoNativeHandler: any,
    streamType: GrpcMethodStreamingType,
  )

   * @param streamType
   */
  public createServiceMethod(
    methodHandler: Function,
    protoNativeHandler: any,
    streamType: GrpcMethodStreamingType,
  ): Function {
    // If proto handler has request stream as "true" then we expect it to have
    // streaming from the side of requester
    if (protoNativeHandler.requestStream) {
      // If any handlers were defined with GrpcStreamMethod annotation use RX
      if (streamType === GrpcMethodStreamingType.RX_STREAMING) {
        return this.createRequestStreamMethod(
          methodHandler,
          protoNativeHandler.responseStream,
        );
      }
      // If any handlers were defined with GrpcStreamCall annotation
      else if (streamType === GrpcMethodStreamingType.PT_STREAMING) {
        return this.createStreamCallMethod(
          methodHandler,
          protoNativeHandler.responseStream,
        );
      }
    }
    return protoNativeHandler.responseStream
      ? this.createStreamServiceMethod(methodHandler)
      : this.createUnaryServiceMethod(methodHandler);
  }

  public createUnaryServiceMethod(methodHandler: Function): Function {
    return async (call: GrpcCall, callback: Function) => {