Flask session support

[tito]

Currently, we can't store anything from the client into the Flask session. Here is a traceback of the issue when trying to use it:

Traceback (most recent call last):
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/eventlet/wsgi.py", line 454, in handle_one_response
    result = self.application(self.environ, start_response)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/engineio/middleware.py", line 32, in __call__
    return self.engineio_app.handle_request(environ, start_response)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/socketio/server.py", line 253, in handle_request
    return self.eio.handle_request(environ, start_response)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/engineio/server.py", line 186, in handle_request
    socket.handle_post_request(environ)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/engineio/socket.py", line 80, in handle_post_request
    self.receive(pkt)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/engineio/socket.py", line 42, in receive
    self.server._trigger_event('message', self.sid, pkt.data)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/engineio/server.py", line 240, in _trigger_event
    return self.handlers[event](*args)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/socketio/server.py", line 394, in _handle_eio_message
    self._handle_connect(sid, pkt.namespace)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/socketio/server.py", line 284, in _handle_connect
    self.environ[sid]) is False:
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/socketio/server.py", line 345, in _trigger_event
    return self.handlers[namespace][event](*args)
  File "/home/tito/code/ninchanese-app/ninchanese/views/stream.py", line 40, in io_connect
    user_id = session.get("user_id")
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/werkzeug/local.py", line 338, in __getattr__
    return getattr(self._get_current_object(), name)
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/werkzeug/local.py", line 297, in _get_current_object
    return self.__local()
  File "/home/tito/.virtualenvs/new-socketio/local/lib/python2.7/site-packages/flask/globals.py", line 20, in _lookup_req_object
    raise RuntimeError('working outside of request context')
RuntimeError: working outside of request context

[miguelgrinberg]

Yes, this project is not Flask specific. If you want to store data per client you can use the storage of your choice. Each client can be referenced by its session id sid variable.

For a Flask specific solution, I'll be updating Flask-SocketIO to use this instead of gevent. I haven't done this yet.

[miguelgrinberg]

You can find the work-in-progress version of Flask-SocketIO that uses this project in branch "eventlet": https://github.com/miguelgrinberg/Flask-SocketIO/tree/eventlet.