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Elegant WebSockets for your Flask apps.

Simple usage ofroute decorator:

fromflaskimportFlaskfromflask_socketsimportSocketsapp=Flask(__name__)sockets=Sockets(app)@sockets.route('/echo')defecho_socket(ws):whilenotws.closed:message=ws.receive()ws.send(message)@app.route('/')defhello():return'Hello World!'if__name__=="__main__":fromgeventimportpywsgifromgeventwebsocket.handlerimportWebSocketHandlerserver=pywsgi.WSGIServer(('',5000),app,handler_class=WebSocketHandler)server.serve_forever()

Usage ofFlask blueprints:

fromflaskimportFlask,Blueprintfromflask_socketsimportSocketshtml=Blueprint(r'html',__name__)ws=Blueprint(r'ws',__name__)@html.route('/')defhello():return'Hello World!'@ws.route('/echo')defecho_socket(socket):whilenotsocket.closed:message=socket.receive()socket.send(message)app=Flask(__name__)sockets=Sockets(app)app.register_blueprint(html,url_prefix=r'/')sockets.register_blueprint(ws,url_prefix=r'/')if__name__=="__main__":fromgeventimportpywsgifromgeventwebsocket.handlerimportWebSocketHandlerserver=pywsgi.WSGIServer(('',5000),app,handler_class=WebSocketHandler)server.serve_forever()

Combining WebSockets with Ajax (XHR) endpoints also comes handy with the support of session handling built-in to sockets as well. As an example you could use an Ajax login call which would create a new session and accordingly set a secure HttpOnly cookie to the browser. After authorization, you can connect to the WebSocket endpoint and reuse the session handling from Flask there as well (as shown here:https://pythonhosted.org/Flask-Session/). Access to other custom cookies is also possible via Flasksrequest.cookies property.

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 bygeventandgevent-websocket.

The given example can run standalone as main.

Anything that insertswsgi.websocket into the WSGI environ issupported, but gevent-websocket is recommended.

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

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

Instead, just use the included gunicorn worker (explained above), or anything thatcan insertwsgi.websocket into the WSGI environ.

The websocket interface that is passed into your routes isprovided by gevent-websocket.The basic methods are fairly straightforward —send,receive,send_frame, andclose.

• Add support ofFlask blueprints.

• 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.