Client

ws4py comes with various client implementations and they roughly share the same interface.

Built-in

The built-in client relies only on modules provided by the Python stdlib. The client’s inner loop runs within a thread and therefore holds the thread alive until the websocket is closed.

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from ws4py.client.threadedclient import WebSocketClient

class DummyClient(WebSocketClient):
    def opened(self):
        def data_provider():
            for i in range(1, 200, 25):
                yield "#" * i

        self.send(data_provider())

        for i in range(0, 200, 25):
            print i
            self.send("*" * i)

    def closed(self, code, reason=None):
        print "Closed down", code, reason

    def received_message(self, m):
        print m
        if len(m) == 175:
            self.close(reason='Bye bye')

if __name__ == '__main__':
    try:
        ws = DummyClient('ws://localhost:9000/', protocols=['http-only', 'chat'])
        ws.connect()
        ws.run_forever()
    except KeyboardInterrupt:
        ws.close()

In this snippet, when the handshake is successful, the opened() method is called and within this method we immediately send a bunch of messages to the server. First we demonstrate how you can use a generator to do so, then we simply send strings.

Assuming the server echoes messages as they arrive, the received_message(message) method will print out the messages returned by the server and simply close the connection once it receives the last sent messages, which length is 175.

Finally the closed(code, reason=None) method is called with the code and reason given by the server.

See also

Managing a pool of WebSockets.

Tornado

If you are using a Tornado backend you may use the Tornado client that ws4py provides as follow:

from ws4py.client.tornadoclient import TornadoWebSocketClient
from tornado import ioloop

class MyClient(TornadoWebSocketClient):
     def opened(self):
         for i in range(0, 200, 25):
             self.send("*" * i)

     def received_message(self, m):
         print m
         if len(m) == 175:
             self.close(reason='Bye bye')

     def closed(self, code, reason=None):
         ioloop.IOLoop.instance().stop()

ws = MyClient('ws://localhost:9000/echo', protocols=['http-only', 'chat'])
ws.connect()

ioloop.IOLoop.instance().start()

gevent

If you are using a gevent backend you may use the gevent client that ws4py provides as follow:

from ws4py.client.geventclient import WebSocketClient

This client can benefit from gevent’s concepts as demonstrated below:

ws = WebSocketClient('ws://localhost:9000/echo', protocols=['http-only', 'chat'])
ws.connect()

def incoming():
    """
    Greenlet waiting for incoming messages
    until ``None`` is received, indicating we can
    leave the loop.
    """
    while True:
        m = ws.receive()
        if m is not None:
           print str(m)
        else:
           break

def send_a_bunch():
    for i in range(0, 40, 5):
       ws.send("*" * i)

greenlets = [
    gevent.spawn(incoming),
    gevent.spawn(send_a_bunch),
]
gevent.joinall(greenlets)