Question

I wrote two applictions which comunicate by socket. This is the code:

Server:

import socket

server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind(("",9999))
server_socket.listen(5)

video = True
power = True

print "TCPServer Waiting for client on port 9999"

while 1:
    client_socket,address = server_socket.accept()
    print "I got a connection from ", address

    while 1:
        data = client_socket.recv(512)
        if data == 'vc' & video == True:
            data = 'You can connect to Video'
            video = False
            client_socket.send(data)
        elif data == 'pc' & power == True:
            data = 'You can connect to Power Switch'
            power = False
            client_socket.send(data)
        else :
            data = 'Device is in use - wait a few secconds'
            client_socket.send(data)

Client:

import socket
import time
client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client_socket.connect(("localhost", 9999))
while 1:
    data = ( 'Please vc or pc: ' )
    time.sleep(5)
    if data=='pc' | data=='vc':
        print 'send to server: ' + data
        time.sleep(5)
        client_socket.send(data)
        data = client_socket.recv(512)
        print data
    else:
        print 'bad data - please try again'

    print data
    time.sleep(5)

I’ve just started my adventure with sockets and I have a problem. Why I don’t see server response? I paste in code time.sleep() to stop the program and see rosponses, but those applications terminate after I wrote first message in client terminal and press enter. Please, help me.

I work on Windows 32bit. Python 2.6

Answer 1

You don’t send anything. I presume the line data = "Please vc or pc: is meant to get input from the user, but it just assigns the string to data. Then when you check if data == 'pc' | data == 'vc' the check fails so it prints “bad data”.

Also do not use | in boolean expressions – use or and and. | and & will do bitwise manipulation – sometimes that will do the right thing, but other times it will bite you in the butt.