Using flask-socketio and handling multiple requests at the same time

[adhrames]

import eventlet
eventlet.monkey_patch()

from server import app, socketio

if name == 'main':
socketio.run(app)

This is the wsgi.py file, socket connections do connect but multiple requests aren't handled and the responses get mixed and the same response is sent to both requests.
gunicorn -k eventlet -w 2 -b 0.0.0.0:8765 wsgi:app, This is the run command I am using, and I am seeing other discussions where it's mentioned eventlet is not suitable anymore,
Can anyone give me proper direction on how to handle multiple requests while also having seperate socket connections to each of them?

[miguelgrinberg]

but multiple requests aren't handled and the responses get mixed

I don't understand what you mean by this. There are no requests and responses in Socket.IO. I think this is likely a misunderstanding on your part on how Socket.IO works.

gunicorn -k eventlet -w 2 -b 0.0.0.0:8765 wsgi:app

See the documentation for how to run Gunicorn with eventlet. The -w 2 is not going to work, use -w 1.

and I am seeing other discussions where it's mentioned eventlet is not suitable anymore,

This is true, but unrelated to the problems that you are having as far as I can see.

Can anyone give me proper direction on how to handle multiple requests while also having seperate socket connections to each of them?

There is nothing special that needs to be done, and there is a working Socket.IO example in the example directory of this repository if you want to get started with working code.

[miguelgrinberg]

This:

    socketio.emit('search_response', acc_search_results_dict)

Is a broadcast. The message is sent to all connected clients. If you want to send only to the sender of the originating event you have to use the context version of emit:

    emit('search_response', acc_search_results_dict)

Of if you prefer to continue using the generic emit, then add the to argument:

    socketio.emit('search_response', acc_search_results_dict, to=request.sid)

Also a side note, your search threads cannot do any heavy CPU work, or else your eventlet application is going to block.

[adhrames]

Okay, So i tried this modification and also sent the request as an argument to the function where emit is again used.
The message is emitted, but on the client side, it's not being received.

My client-side code:

ControllerViewModel.prototype._socketConnections = async function () {
  
    var socket = io('http://100.111.148.112:8765', {
      transports: ['websocket']  // Only allow WebSocket transport
  });

    socket.on('connect', async () => {
        console.log('Connected to Flask Socket.IO server');   
    });

    socket.on('search_update', async (statusUpdate) => {
      console.log(statusUpdate);
      console.log('Search count updated:', statusUpdate.search_count, 'at', new Date().toISOString());
      totalCount = this.finalProductCount();
      completionPercentage = Math.round((statusUpdate.search_count/totalCount)*100);

      const lastHyphenIndex = statusUpdate.update_string.lastIndexOf('_');
      const productName = statusUpdate.update_string.substring(0, lastHyphenIndex);  // Text before the last hyphen
      const searchType = statusUpdate.update_string.substring(lastHyphenIndex + 1); // Text after the last hyphen
      let searchprogressText = "Shiphome " + productName + " searched for the " + searchType;
      this.searchProgressString(searchprogressText);

      console.log(completionPercentage);
      this.searchProgress(completionPercentage);
      // Update the Knockout observable
      //
    });

    socket.on('search_response', async (dataFromService) => {
      this.searchProgress(100);
      this.searchResults(dataFromService);
      this.afterSocketResponse();
      console.log('Search completed!');
      if (dataFromService.error) {
          console.error(dataFromService.error);
      } else {
          console.log('Search completed!', dataFromService);
      }
    });

   }

This function includes all the socket connection handling,

On a different function which activated after the user clicks on a submit button on the ui,

   var socket2 = io('http://100.111.148.112:8765');
    socket2.emit('search_request', jsonServiceRequest);

And regarding the CPU heavy work, what do you recommend? I am not very strict on the worker-class, I just want socket.io to work.

[miguelgrinberg]

I'm sorry, but I don't understand what you are showing me. You shouldn't have two different sockets, each client has to have one socket connection. I really think you should look at working examples of Socket.IO apps instead of trying to improvise a solution.

And regarding the CPU heavy work, what do you recommend? I am not very strict on the worker-class, I just want socket.io to work.

I can't recommend anything. Eventlet does not work with CPU heavy tasks.

[adhrames]

I can't recommend anything. Eventlet does not work with CPU heavy tasks.

Yeah, I get that. But, I am not fixed on eventlet. What should I be using instead?

[miguelgrinberg]

Eventlet is optional. Just don't use it. If you uninstall it from your virtualenv, then Flask-SocketIO is going to use standard threads for concurrency.