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POVery simple python client/server working, but strange delays
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copied!<p>I am trying to learn how to use sockets and a useful asynchronous backend. I've started in python with asyncore. After reading various online posts I've written a very simple chat server and connection client, reproduced below.</p> <p>It seems to work. I open a python interactive session and type</p> <pre><code>> import chatserver > server = chatserver.EchoServer('localhost', 7667) > server.serve() </code></pre> <p>Then I open another IPython interactive session and type</p> <pre><code>> import chatserver > cxn = chatserver.Connection() > cxn._connect('localhost', 7667) </code></pre> <p>When I do that, I get a log output in the server window indicating that a connection has been made. Good. Then I type</p> <pre><code>> cxn.say('hi') </code></pre> <p>Nothing happens for a while, and then log messages show up for the server and client as expected.</p> <ol> <li>Why is this delay ocurring?</li> <li>Am I using the log functionality correctly?</li> <li>I used threading to make it so that I could use the interactive session while the asyncore loop does it's thing for the Connection. Did I do this in a reasonable way?</li> <li>(optional) If I don't include the line <code>self.out_buffer=""</code> in the Connection._connect function I get an error saying that .out_buffer does not exist. What's up with this?</li> </ol> <pre class="lang-python prettyprint-override"><code>import asyncore import socket import logging import threading logging.basicConfig(level=logging.DEBUG, format="%(created)-15s %(msecs)d %(levelname)8s %(thread)d %(name)s %(message)s") log = logging.getLogger(__name__) class Connection(asyncore.dispatcher_with_send): def __init__(self): asyncore.dispatcher.__init__(self) def _connect(self, host, port, timeout=5, password=None): self.host = host self.port = port self.out_buffer="" self.create_socket(socket.AF_INET, socket.SOCK_STREAM) self.connect((host, port)) #Run the asyncore loop in its own thread so that we can use the interactive session self.loop = threading.Thread(target=asyncore.loop) self.loop.daemon = True self.loop.start() def say(self, msg): self.out_buffer = msg def handle_read(self): data = self.recv(4096) log.debug('Received %s'%data) class EchoHandler(asyncore.dispatcher_with_send): def handle_read(self): log.debug("handle_read") data = self.recv(1024) log.debug("after recv") if data: log.debug("got data: %s"%data) self.out_buffer = data else: log.debug("got null data") class EchoServer(asyncore.dispatcher): SOCKET_TYPE = socket.SOCK_STREAM ADDRESS_FAMILY = socket.AF_INET def __init__(self, host, port): self.address = (host,port) asyncore.dispatcher.__init__(self) self.create_socket(self.ADDRESS_FAMILY, self.SOCKET_TYPE) log.debug("bind address=%s %s"%(host,port)) self.bind(self.address) self.listen(1) def fileno(self): return self.socket.fileno() def serve(self): asyncore.loop() #Start asyncore loop in new thread # self.loop = threading.Thread(target=asyncore.loop) # self.loop.daemon = True # self.loop.start() def handle_accept(self): """Deal with a newly accepted client""" (connSock, clientAddress) = self.accept() log.info("conn made: clientAddress=%s %s"%(clientAddress[0], clientAddress[1])) #Make a handler for this connection EchoHandler(connSock) def handle_close(self): self.close() </code></pre>

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