You are here: Home / Past Courses / Spring 2017 - ECPE 170 / Labs / Example Python3 Client

Example Python3 Client

Python Source icon client.py — Python Source, 1 KB (1870 bytes)

File contents

#!/usr/bin/env python3

# Simple network socket demo - CLIENT
#
# Set script as executable via: chmod +x client.py
# Run via:  ./client.py <IP> <PORT>
#
# To connect to a server on the same computer, <IP> could
# either be 127.0.0.1 or localhost (they have the same meaning)

import socket
import sys

def main():
    if len(sys.argv) != 3:
        print("Error: Program needs <IP> and <PORT> arguments")
        sys.exit()

    # Tip: You should use argparse - this method
    # is sloppy and inflexible
    ip = sys.argv[1]
    port = int(sys.argv[2])
    
    # Create TCP socket
    try:
        s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    except socket.error as msg:
        print("Error: could not create socket")
        print("Description: " + str(msg))
        sys.exit()

    print("Connecting to server at " + ip + " on port " + str(port))
     
    # Connect to server
    try:
        s.connect((ip , port))
    except socket.error as msg:
        print("Error: Could not open connection")
        print("Description: " + str(msg))
        sys.exit()
 
    print("Connection established")
    
    # Send message to server
    string_unicode = "Tiger Roar!"
    raw_bytes = bytes(string_unicode,'ascii')
    
    try:
        # Send the string
        # Note: send() might not send all the bytes!
        # You should loop, or use sendall()
        bytes_sent = s.send(raw_bytes)
    except socket.error as msg:
        print("Error: send() failed")
        print("Description: " + str(msg))
        sys.exit()
 
    print("Sent %d bytes to server" % bytes_sent)

    # Close socket
    try:
        s.close()
    except socket.error as msg:
        print("Error: unable to close() socket")
        print("Description: " + str(msg))
        sys.exit()

    print("Sockets closed, now exiting")

if __name__ == "__main__":
    sys.exit(main())