SocketServer class examples

Adil Hasan hasan at in2p3.fr
Sat Dec 11 17:53:55 CET 2004


Hello Fred,
           I just ran across your question. I think that the following
code will work:

----- SERVER CODE ------
import SocketServer
import time
class GreetingHandler(SocketServer.BaseRequestHandler):
    '''Class to handle sending a greeting to a client
    '''
    def handle(self):
        '''Method to actually handle the greeting
        '''
        print 'handling the request'
        line = self.request.recv(bufsize)
        name = ""
        if ('NAME:' in line):
           name = line.split('NAME:')[1]
        self.request.sendall('hello there %s \n' % name)

def manageServer():
    '''Function to manage the running of the server and handling of
requests
    '''
    servObj = SocketServer.TCPServer(('localhost',6099),GreetingHandler)
    print 'Starting the server...'
    servObj.serve_forever()

if __name__ == '__main__':
    manageServer()

----- CLIENT CODE -----
#!/usr/bin/env python
import socket
def manageClient():
    '''Function to manage the sending of request to the server
    '''
    server = 'localhost'
    port   = 6099
    servObj = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    servObj.connect((server, port))
    servObj.send('NAME: An Elephant\r\n')
    resp = servObj.recv(8192)
    print resp
    servObj.close()

if __name__ == '__main__':
    manageClient()



I think that the problem with the rfile and wfile methods in the
StreamRequestHandler class is that it's trying to send on the
same socket as it's reading data on so they are blocking each
other. I think that this is a problem in the StreamRequestHandler
class.

adil

-----Original Message-----
From: Frederick Grim [mailto:fgrim at norby.dyndns.org]
Sent: 18 July 2004 19:34
To: python-list at python.org
Subject: SocketServer class examples

Howdy group,
    So I am in the middle of using the socketserver class from the std
library and have run into a problem that probably reveals my
misunderstanding of sockets.  I have a class defined like so:

class tcp_listener(SocketServer.ThreadingTCPServer):
        def __init__(self, addr, port):
                SocketServer.ThreadingTCPServer.__init__(self, \
                    (addr, port), Daemon.request_handler)

""" Yes I realize the above is silly and redundant """

And a request handler in Daemon that has a handle function that works like
so:
    def __req_handle(self, req):
        """ Do stuff with req and return a response afterwards """
        return response

    def handle(self);
        while True:
            input = self.rfile.readline()
            request = input
            while input and not re.search('EOF$', input):
                input = self.rfile.readline()
                request += input

            self.wfile.write(self.__req_handle(request))

The client end looks almost identical to the example in the python docs.
So
the problem here is that this code doesn't work.  Using tcpdump I can tell
that the client is sending to the server properly but the server is never
responding.  Or when it tries to respond it gets stuck in the write.
What's
going on here.  I can't seem to find a single example of how to use this
class on the client and server side and I don't want to use twisted
(because
I should understand how this works instead of relying on canned software).
Does anyone know where I can find an example of a functioning SocketServer
and client? Google seems to help nought here.
    Thanks,
    Fred









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