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| # Copy of http://stackoverflow.com/a/20104705 | |
| from flask import Flask, render_template | |
| from flask_sockets import Sockets | |
| app = Flask(__name__) | |
| app.debug = True | |
| sockets = Sockets(app) | |
| @sockets.route('/echo') | |
| def echo_socket(ws): | |
| while True: | |
| message = ws.receive() | |
| ws.send(message[::-1]) | |
| @app.route('/') | |
| def hello(): | |
| return 'Hello World!' | |
| @app.route('/echo_test', methods=['GET']) | |
| def echo_test(): | |
| return render_template('echo_test.html') | |
| if __name__ == '__main__': | |
| app.run() |
| <!DOCTYPE html> | |
| <html> | |
| <head> | |
| <script type="text/javascript"> | |
| var ws = new WebSocket("ws://localhost:8000/echo"); | |
| ws.onopen = function() { | |
| ws.send("socket open"); | |
| }; | |
| ws.onclose = function(evt) { | |
| alert("socket closed"); | |
| }; | |
| ws.onmessage = function(evt) { | |
| alert(evt.data); | |
| }; | |
| </script> | |
| </head> | |
| </html> |
Thanks for the snippet. It was very useful!
I hate to be stupid, but where does the 8000 come from?
It is the target port specified in the client-side call to /ws, but I don't see where the server is told to bind to it.
The flask (dev) server returns a 404 on /echo, but it works by running a server with gunicorn: gunicorn -k flask_sockets.worker hello:app
Oh, wow, I didn't know this gist had any views, until GitHub now shows notifications for gists too.
Hi, I tried the same sample given, i am getting the following error in browser concole
Emulator.js:82 WebSocket connection to 'ws://127.0.0.1:5000/echo' failed: Error during WebSocket handshake: Unexpected response code: 404
I've tried gunicorn and various other ways to make this work but I just get a 404.
I've tried gunicorn and various other ways to make this work but I just get a
404.
Have you tried starting the flask app with gunicorn, using the parameter --worker-class flask_sockets.worker?
Also, this is working for ping/pong, ws.handler.websocket.send_frame("HB", ws.OPCODE_PING)
@sockets.route("/ws/stream")
def websocket(ws):
messages_backend.register(ws)
while not ws.closed:
message = ws.receive()
LOG.debug(f"message: {message}")
ws.handler.websocket.send_frame("HB", ws.OPCODE_PING)
# Context switch while `MessagesBackend.start` is running in the background.
gevent.sleep(1)
The flask_sockets project is now archived and unsupported. We @AdaSupport had issues running it with gunicorn. This snippet solved our problem:
# NOTE: https://stackoverflow.com/a/64002375/2114288
import grpc.experimental.gevent as grpc_gevent
grpc_gevent.init_gevent()
Unfortunately, this won't work. I tried to build very small web-server as GUI for another background process. Of course, I wanted to see feedback from my app to appear immediately on the HTML-page. Websocket should do the work perfect, but flask_socket does not support WebSocket on the client side. Instead, your JS client should use io.connect Take a look here:
https://blog.miguelgrinberg.com/post/easy-websockets-with-flask-and-gevent