could we ack when we receive a new event

[magamal]

`socket.on("new_message",(data)=>{

//How to ack this event?
})'`

[jumperchen]

Fyi, https://github.com/rikulo/socket.io-client-dart?tab=readme-ov-file#acknowledge-with-the-socket-server-that-an-event-has-been-received

[magamal]

Yes I read it before, but if I'm receiving a string from the server how I can ack this event

socket.on("new_message",(data)=>{
final String messageContent = data;
}

[steveroseik]

Yes I read it before, but if I'm receiving a string from the server how I can ack this event

socket.on("new_message",(data)=>{ final String messageContent = data; }

Heyy, I had the same issue and figured out the solution.

It's pretty easy, it's the lack of information in the documentation that makes it hard to figure out.

I'll show you my example:

in my server side I send a nudge to the client, when you send it, the client receives a list of data, consists of the data you sent in the emit and an extra callback function that should be used for acks:

so this is how the data might look like if you used my code below:

['Input the data to be sent.', function()]

this.server
        .to(opponentId)
        .timeout(5000)
        .emit(
          'nudge',
          'Input the data to be sent.',
          (err, responses) => {
            if (err) {
              /// handle timeout
            } else {
              // handle responses
            }
          },
        );

That's why in flutter you'll need to treat the data received as a list, and extract from it both data sent from server and the function;

you can handle the data as you like, and the take the last item as Function and run it as described in their code sample:

socket.on('nudge', (data) {
    final dataList = data as List;

    final customData = dataList.first;

    final ack = dataList.last as Function;
    ack(null);
});

[makamekm]

It stopped working in version 3. Rolled back to 2.

Uncaught (in promise) DartError: NoSuchMethodError: ''
Dynamic call with too many positional arguments. Expected: 2 Actual: 3
Receiver: Instance of '(String, dynamic) => Null'
Arguments: ["report", Instance of '_JsonMap', Instance of '(dynamic) => Null']
    at Object.throw_ [as throw] (errors.dart:296:3)
    at Object.defaultNoSuchMethod (operations.dart:913:3)
    at Function.noSuchMethod (core_patch.dart:63:17)
    at Object.noSuchMethod (operations.dart:888:31)
    at callNSM (operations.dart:318:12)
    at Object._checkAndCall (operations.dart:428:10)
    at Object.dcall (operations.dart:451:39)
    at Function.apply (core_patch.dart:103:17)
    at socket$0.Socket.new.emitEvent (socket.dart:457:18)
    at socket$0.Socket.new.onevent (socket.dart:447:7)
    at socket$0.Socket.new.onpacket (socket.dart:412:9)
    at Object._checkAndCall (operations.dart:426:37)
    at Object.dcall (operations.dart:451:39)
    at event_emitter.dart:44:14
    at [dartx.forEach] (js_array.dart:212:7)
    at [_emit] (event_emitter.dart:43:11)
    at manager.Manager.new.emitReserved (event_emitter.dart:57:47)
    at manager.dart:276:7
    at async._AsyncCallbackEntry.new.callback (future.dart:285:40)
    at Object._microtaskLoop (schedule_microtask.dart:40:11)
    at _startMicrotaskLoop (schedule_microtask.dart:49:5)
    at async_patch.dart:181:7

[jumperchen]

@makamekm Could you provide a reproducible example?

[makamekm]

@jumperchen I just fixed it. The error is here:

Solution in one line:

The issue that the type of the listener has only 2 args with 3 inputs comparing to non ack version.

[makamekm]

Or like this