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https://github.com/zeekay/flask-uwsgi-websocket

🔌 High-performance WebSockets for your Flask apps powered by uWSGI.
https://github.com/zeekay/flask-uwsgi-websocket

flask python uwsgi websockets

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🔌 High-performance WebSockets for your Flask apps powered by uWSGI.

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README 

        
Flask-uWSGI-WebSocket

=====================

High-performance WebSockets for your Flask apps powered by `uWSGI

`_. Low-level uWSGI WebSocket API

access and flexible high-level abstractions for building complex WebSocket

applications with Flask. Supports several different concurrency models

including Gevent. Inspired by `Flask-Sockets

`_.



.. code-block:: python



    from flask import Flask

    from flask_uwsgi_websocket import GeventWebSocket



    app = Flask(__name__)

    websocket = GeventWebSocket(app)



    @websocket.route('/echo')

    def echo(ws):

        while True:

            msg = ws.receive()

            ws.send(msg)



    if __name__ == '__main__':

        app.run(gevent=100)



Installation

------------

Preferred method of installation is via pip::



    $ pip install Flask-uWSGI-WebSocket



Installing uWSGI

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Of course you'll also need uWSGI (with SSL support, at minimum). It can also be

installed with pip::



    $ pip install uwsgi



If that fails or you need to enable the asyncio plugin, read on.



uWSGI on Mac OS X

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

On some versions of Mac OS X, OpenSSL headers are no longer included. If you

use Homebrew, install OpenSSL and ensure they are available::



    $ brew install openssl && brew link openssl --force



This should ensure pip can install uWSGI::



    $ LDFLAGS="-L/usr/local/lib" pip install uwsgi --no-use-wheel



If you plan to use the asyncio plugin, you'll need to ensure that it's enabled

when uWSGI is compiled. You can use ``UWSGI_PROFILE`` to do this. With Homebrew Python 3.5 installed::



    $ LDFLAGS="-L/usr/local/lib" CFLAGS="-I/usr/local/include/python3.5m" UWSGI_PROFLILE="asyncio" pip3 install uwsgi --no-use-wheel



uWSGI on Linux

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

If your Linux distribution includes uWSGI with specific plugins, that is many

times your best bet. If that fails or you'd prefer to compile uWSGI yourself,

you'll need to ensure that the requisite build tools, OpenSSL headers, etc are

installed::



    $ apt-get install build-essential libssl-dev python3-dev python3-venv



According to the `uWSGI asyncio docs

`_, ``UWSGI_PROFILE``

and ``greenlet.h`` location should be specified.



If you are installing uWSGI into a virtualenv, the process is::



    $ python3 -m venv pyvenv

    $ . pyvenv/bin/activate

    (pyvenv)$ pip install greenlet



Now, ``greenlet.h`` should be available at ``$VIRTUAL_ENV/include/site/python3.5``. To build with pip::



    $ mkdir -p $VIRTUAL_ENV/include/site/python3.5/greenlet

    $ ln -s ../greenlet.h $VIRTUAL_ENV/include/site/python3.5/greenlet/

    $ CFLAGS="-I$VIRTUAL_ENV/include/site/python3.5" UWSGI_PROFILE="asyncio" pip install uwsgi --no-use-wheel



Deployment

----------

You can use uWSGI's built-in HTTP router to get up and running quickly::



    $ uwsgi --master --http :8080 --http-websockets --wsgi echo:app



...which is what ``app.run`` does after wrapping your Flask app::



    app.run(debug=True, host='localhost', port=8080, master=true, processes=8)



uWSGI supports several concurrency models, in particular it has nice support

for Gevent. If you want to use Gevent, import

``flask_uwsgi_websocket.GeventWebSocket`` and configure uWSGI to use the

gevent loop engine::



    $ uwsgi --master --http :8080 --http-websockets --gevent 100 --wsgi echo:app



...or::



    app.run(debug=True, gevent=100)



Note that you cannot use multiple threads with gevent loop engine.



To enable asyncio instead::



    $ uwsgi --master --http :5000 --http-websockets --asyncio 100 --greenlet --wsgi chat:app



...or::



    app.run(debug=True, asyncio=100, greenlet=True)



For production you'll probably want to run uWSGI behind Haproxy or Nginx,

instead of using the built-int HTTP router. Explore the `uWSGI documentation

`_ to learn more

about the various concurrency and deployment options.



Development

-----------

It's possible to take advantage of Flask's interactive debugger by installing

Werkzeug's ``DebuggedApplication`` middleware::



    from werkzeug.debug import DebuggedApplication

    app.wsgi_app = DebuggedApplication(app.wsgi_app, True)



...and running uWSGI with only a single worker::



    $ uwsgi --master --http :8080 --http-websockets --wsgi-file --workers 1 --threads 8 app.py



If you use ``app.run(debug=True)`` or export ``FLASK_UWSGI_DEBUG``,

Flask-uWSGI-Websocket will do this automatically for you.



Examples

--------

There are several examples `available here `_.



API

---



``WebSocket``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Applies ``WebSocketMiddleware`` to your Flask App, allowing you to decorate

routes with the ``route`` method, turning them into WebSocket handlers.



Additionally monkey-patches ``app.run``, to run your app directly in uWSGI.



``route(url)``



``run(debug, host, port, **kwargs)``

``**kwargs`` are passed to uWSGI as command line arguments.



``WebSocketMiddleware``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

WebSocket Middleware which automatically performs WebSocket handshake and

passes ``WebSocketClient`` instances to your route.



``WebSocketClient``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Exposes the `uWSGI WebSocket API

`_.



``recv()`` (alias ``WebSocket.receive()``)



``recv_nb()``



``send(msg)``



``send_binary(msg)``



``recv_nb()``



``send_from_sharedarea(id, pos)``



``send_binary_from_sharedarea(id, pos)``



``GeventWebSocket``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fancier WebSocket abstraction that takes advantage of Gevent loop engine.

Requires uWSGI to be run with ``--uwsgi`` option.



``GeventWebSocketMiddleware``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Automatically performs WebSocket handshake and passes a

``GeventWebSocketClient`` instance to your route.



``GeventWebSocketClient``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

WebSocket client abstraction with fully non-blocking methods.



``receive()``



``send(msg)``



``close()``



``connected``



``AsyncioWebSocket``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Fancier WebSocket abstraction that takes advantage of Asyncio loop engine.

Requires uWSGI to be run with ``--asyncio`` and ``--greenlet`` option.



``AsyncioWebSocketMiddleware``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Automatically performs WebSocket handshake and passes a ``AsyncioWebSocketClient`` instance to your route.



``AsyncioWebSocketClient``

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

WebSocket client abstraction with asyncio coroutines.



``coroutine a_recv()`` (alias ``receive()``, ``recv()``)



``coroutine a_send(msg)`` (alias ``send()``)



``recv_nb()`` (should be useless)



``send_nb()`` (should be useless)



``close()``



``connected``



Advanced Usage

--------------

Normally websocket routes happen outside of the normal request context. You can

get a request context in your websocket handler by using

``app.request_context``::



    app = Flask(__name__)

    ws = GeventWebSocket(app)



    @ws.route('/websocket')

    def websocket(ws):

        with app.request_context(ws.environ):

            print request.args