How to send acknowledgment from Socket.IO server?

Question

I'm having trouble sending acknowledgements from my socket.IO server. I've followed the documentation and added a function "fn" to my message handler function. Unfortunately fn is undefined. What's wrong with my code?

socket.on('search', function (searchParamsFromClient, fn) {

maybe this helps: http://stackoverflow.com/questions/20417569/acknowledgment-for-socket-io-custom-event — brandelizer, Dec 17 '15 at 10:57
Thank you, but it seems that's almost the same code I've wrote. My question is why is my callback, fn, undefined? — Erik Z, Dec 17 '15 at 11:12
You should show the code you're using on "the other side" (the emitter of `search`), because that's where the callback is actually defined. — robertklep, Dec 17 '15 at 11:13
@robertklep Thank you. You're right, I had to add a callback to the emitter-call. — Erik Z, Dec 17 '15 at 12:28

score 3 · Accepted Answer · answered Sep 30 '17 at 10:02

3

The function 'fn' needs to be defined on the other side of the socket, i.e., the client.

Server:

socket.on('search', function (searchParamsFromClient, ack) {
  // do something with searchParamsFromClient
  ack();
}

Client:

socket.emit('search', searchPayload, function() {
  // acknowledgement
  // This function is what gets called as ack()
});

answered Sep 30 '17 at 10:02

vantony

513
6
9

Simple explanation and easy to understand. Thanks ! – Arief Wijaya Mar 06 '21 at 04:16

How to send acknowledgment from Socket.IO server?

1 Answers1