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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.
.. code-block:: python
:linenos:
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 :meth:`opened() <ws4py.websocket.WebSocket.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 :func:`received_message(message) <ws4py.websocket.WebSocket.received_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 :func:`closed(code, reason=None) <ws4py.websocket.WebSocket.closed>` method is called with the code and reason given by the server.
.. seealso::
:ref:`manager`.
Tornado
-------
If you are using a Tornado backend you may use the Tornado client that ws4py provides as follow:
.. code-block:: python
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:
.. code-block:: python
from ws4py.client.geventclient import WebSocketClient
This client can benefit from gevent's concepts as demonstrated below:
.. code-block:: python
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)
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