a method and a class for interacting over a socket

gistfile1.txt

class Listener(object):
    """
    This accepts a list of `commands` and associated `responses` and opens a
    socket on `port`.  It then listens for any of the commands and dumps
    the associated response.

    Example:

    Listener.listen(port=57359, 
                    commands = [  "give_me_your_name",
                                  "give_me_your_slogan" ],
                    responses = [ "nationwide",
                                  "on your side!" ])

    Connecting to port 57359 from another host and issuing "give_me_your_name" 
    would then send "nationwide" in response, and issuing "give_me_your_slogan"
    would respond with "on your side!".

    This could be used for passing around config files without going through
    SSH, etc.

    Returns the name of the host that connected.

    See connect() for the sister method.
    """

    def __init__(self):
        self.s_listen = None

    def listen(self, commands, responses, port=57359):

        HOST = ''
        PORT = port

        if not self.s_listen:
            self.s_listen = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
            self.s_listen.bind((HOST, PORT))
            self.s_listen.listen(1)
        conn, addr = self.s_listen.accept()

        host = socket.gethostbyaddr(addr[0])
        while 1:
            data = conn.recv(1024)
            for command in commands:
                try:
                    data.index(command)
                    conn.sendall(responses[commands.index(command)])
                    conn.close()
                    return host[0]
                except ValueError: pass


def connect(node, command, port=57359):
    """
    Connects to `node` on `port` and issues `command`.  Assumes that `node`
    is already listening on the provided port and knows how to respond to
    `command`.

    Raises exception if a connection cannot be established, else returns the
    response issued by the host in response to `command`.

    See Listener() for the sister class.
    """

    HOST = node
    PORT = port
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

    try:
        s.connect((HOST,PORT))
    except:
        s.close()
        raise
    s.sendall(command)

    response = ""

    while 1:
        data = s.recv(1024)
        if not data: break
        response += data

    s.close()
    return response