Python - Server and client problems

Question

I\'m trying to create a basic server and client script. The idea is that the client can connect to the server and execute commands. Kinda like SSH but very simple. Heres my

Answer 1

When you makefile() on the socket and then use readlines() on it, it will continue until you reach an end of file, which in the socket case is that it closed from the other end.

Using makefile() in this case makes no sense to me, especially since you create it and close it after each command. Just use send() and recv() on both ends.

You probably also want to have some sort of actual "protocol" so the server tells the client "HERE COMES A RESPONSE" and "THIS IS THE END OF THE RESPONSE" so that the client knows. Otherwise it gets hard to know when to stop waiting for more response. :)

Update with an example that works:

server.py:

import sys, os, socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(('', 50500))
print("Server started")
s.listen(1)
while True:
    print "Accepting"
    conn, addr = s.accept()
    print 'New connection from ', addr
    while True:
        try:
            rc = conn.recv(1024)
            print "Command", rc
            if not rc.strip():
                continue

            if rc.strip() == 'END':
                print "Close"
                conn.send("**END**")
                conn.close()
                break
            else:
                conn.send("This is the result of command %s\n" % rc)
        except Exception:
            conn.close()
            sys.exit()

client.py

import sys, os, socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(('localhost', 50500))
while True:
    cmd = raw_input('$ ')
    s.send(cmd) 
    result = s.recv(1024)
    print result
    if result == "**END**":
        print "Ending"
        break

Answer 2

Well for one thing you're only connecting on the client once and on the server you're closing the socket after every read.

You should take a look at this example.

http://ilab.cs.byu.edu/python/socket/echoserver.html

You're doing quite a few things incorrectly.