Why cant I use gevent websockets inside a greenlet

Question

I'm trying to receive websocket messages in a greenlet, but it doent seem to be working. I have this code:

import gevent
from geventwebsocket.handler import WebSocketHandler
from gevent.pywsgi import WSGIServer
from geventwebsocket import WebSocketServer, WebSocketApplication, Resource



def recvWs(ws):
    gevent.sleep(0)
    recvedData = ws.receive()
    rData = json.loads(recvedData)
    print(rData)

def app(environ, start_response):


    websocket = environ['wsgi.websocket']

    while True:
        gevent.spawn(recvWs,websocket)
        gevent.sleep(0)

if __name__ == '__main__':
    server = WSGIServer(("0.0.0.0", 80), app,handler_class=WebSocketHandler)
    server.serve_forever()

And when running, it returns this error:

<Greenlet "Greenlet-0" at 0x23fa4306148: 
recvWs(<geventwebsocket.websocket.WebSocket object at 0x0)> failed with 
RuntimeError

As well as:

line 197, in read_frame
header = Header.decode_header(self.stream)

How do I fix this?

Answer 1

Here is an example of what I have done that works very well.
Python with bottle and gevent:

from gevent import sleep as gsleep, Timeout
from geventwebsocket import WebSocketError
from bottle import Bottle, get, post, route, request, response, template, redirect, abort

@route('/ws/app')
def handle_websocket():
    wsock = request.environ.get('wsgi.websocket')
    if not wsock:
        abort(400, 'Expected WebSocket request.')
    # Send initial data here
    wsock.send(json.dumps(data))
    while 1:
        try:
            #Process incoming message.  2 second timeout to not block
            message = {}
            with Timeout(2, False) as timeout:
                message = wsock.receive()
            if message:
                message = json.loads(message)
                if isinstance(message, dict):
                     # Do something with data and return
                     wsock.send(json.dumps(result))
            # Add an additional second just for sanity.  Not necessarily needed
            gsleep(1)
        except WebSocketError:
            break
        except Exception as exc:
            traceback.print_exc()
            gsleep(2)

Then in your javascript you open a websocket connection and send and recieve the data as you would normally.