Basically, I have a socket io flask code:
import cv2 import numpy as np from flask import Flask, render_template from flask_socketio import SocketIO, emit from threading import Lock,Timer as tmr from engineio.payload import Payload import base64 from PIL import Image import io app = Flask(__name__) app.config['SECRET_KEY'] = 'secret!' socketio = SocketIO(app) @socketio.on('connect') def connect(): print("a client connected") @socketio.on('disconnect') def disconnect(): print('Client disconnected') @app.route('/') def hello(): return render_template('index.html') if __name__ == '__main__': socketio.run(app,port=port,host= '0.0.0.0')
This code is working fine when I try to connect it to javascript
However in flutter I can not achieve that
I have stateful Widget that has a button in it And I am using this function to connect to my socket when the button is pressed
import 'package:socket_io_client/socket_io_client.dart' as IO; IO.Socket socket; connectToSocket() { socket = IO.io("http://10.0.2.2:6400", <String, dynamic>{ 'transports': ['websocket', 'polling'], }); socket.connect(); }
I can not connect it please help me.
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Answer
I know this is an older question but hopefully this answer will help someone down the road.
The issue may be caused by the lack of support for polling in flutter.
from: https://github.com/rikulo/socket.io-client-dart#usage-flutter
In Flutter env. it only works with dart:io websocket, not with dart:html websocket, so in this case you have to add ‘transports’: [‘websocket’] when creates the socket instance.
IO.Socket socket = IO.io('http://localhost:3000', <String, dynamic>{ 'transports': ['websocket'], 'extraHeaders': {'foo': 'bar'} // optional });
The default Flask development server doesn’t support websockets so you’ll need to use another server. Thankfully it’s simple to get eventlet working with Flask. All you should have to do is install the eventlet package using pip.
pip install eventlet
Once eventlet is installed socketio will detect and use it when running the server.
You can use chrome to double check what transport method is being used. Open your chrome dev tools Ctrl+Shift+I
in Windows and go to the Network tab. On each network request you should see either transport=polling
or transport=websocket