RPC Response

The RPC response object is passed to the callback registered with client.rpc.provide(). It allows RPC providers to decide how to react to an incoming request.

Methods

response.send( data )

Succesfully complete a remote procedure call and send data back to the requesting client.

data can be any kind of serializable data, e.g. Objects, Numbers, Booleans or Strings

client.rpc.provide( 'add-two-numbers', ( data, response ) => {
  response.send( data.numA + data.numB );
});

response.reject()

Rejects the request. Rejections are not errors, but merely a means of saying "I'm busy at the moment, try another provider". Upon receiving a rejection deepstreamHub will try to re-route the request to another provider for the same RPC. If there are no more providers left to try, deepstream will send a NO_RPC_PROVIDER error to the client.

client.rpc.provide( 'add-two-numbers', ( data, response ) => {
  //reject the response so that it gets
  //re-routed to another provider
  response.reject();
});

response.error( errorMsg )

Send an error to the client. errorMsg will be received as the first argument to the callback registered with client.rpc.make(). This will complete the RPC.

client.rpc.provide( 'count-vote', ( data, response ) => {
  if( hasAlreadyVoted( data.user ) ) {
   response.error( 'You can only vote once' );
  }
});

response.ack()

Explicitly acknowledges the receipt of a request.

This is usually done automatically, but can also be performed explicitly by setting response.autoAck = false and calling ack() later. This is useful when a client needs to perform an asynchronous operation to determine if it will accept or reject the request.

client.rpc.provide( 'resize-image', ( data, response ) => {
  // Turn of automatic acknowledgements. This needs to happen synchronously
  response.autoAck = false;

  // Acknowledge the request yourself at a later point
  hasCapacities().then(() => {
    response.ack();
  });
});