Elegant WebSockets for your Flask apps.

from flask import Flask
from flask_sockets import Sockets

app = Flask(__name__)
sockets = Sockets(app)

@sockets.route('/echo')
def echo_socket(ws):
    while not ws.closed:
        message = ws.receive()
        ws.send(message)

@app.route('/')
def hello():
    return 'Hello World!'


if __name__ == "__main__":
    from gevent import pywsgi
    from geventwebsocket.handler import WebSocketHandler
    server = pywsgi.WSGIServer(('', 5000), app, handler_class=WebSocketHandler)
    server.serve_forever()

Serving WebSockets in Python was really difficult. Now it's not.

To install Flask-Sockets, simply:

$ pip install Flask-Sockets

A custom Gunicorn worker is included to make deployment as friendly as possible:

$ gunicorn -k flask_sockets.worker hello:app

Production services are provided by gevent and gevent-websocket.

The given example can run standalone as main.

Anything that inserts wsgi.websocket into the WSGI environ is supported, but gevent-websocket is recommended.

Because the Werkzeug development server cannot provide the WSGI environ with a websocket interface, it is not possible to run a Flask app using the standard app.run().

If you try to, Flask will still try to serve on all the specified routes, and throw a KeyError whenever a client tries to connect to a websocket route.

Instead, just use the included gunicorn worker (explained above), or anything that can insert wsgi.websocket into the WSGI environ.

The websocket interface that is passed into your routes is provided by gevent-websocket. The basic methods are fairly straitforward — send, receive, send_frame, and close.

• Add request context into the socket handler.
• Fallback to Flask logic if websocket environment is not available.
• Use Flask routing to allow for variables in URL

• Initial release.