Python Networking

Remarks#

https://stackoverflow.com/questions/7749341/very-basic-python-client-socket-example

The simplest Python socket client-server example

Server side:

import socket

serversocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
serversocket.bind(('localhost', 8089))
serversocket.listen(5) # become a server socket, maximum 5 connections

while True:
    connection, address = serversocket.accept()
    buf = connection.recv(64)
    if len(buf) > 0:
        print(buf)
    break

Client Side:

import socket

clientsocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
clientsocket.connect(('localhost', 8089))
clientsocket.send('hello')

First run the SocketServer.py, and make sure the server is ready to listen/receive sth Then the client send info to the server; After the server received sth, it terminates

Creating a Simple Http Server

Creating a TCP server

You can create a TCP server using the socketserver library. Here’s a simple echo server.

Server side

from sockerserver import BaseRequestHandler, TCPServer

class EchoHandler(BaseRequestHandler):
    def handle(self):
        print('connection from:', self.client_address)
        while True:
            msg = self.request.recv(8192)
            if not msg:
                break
            self.request.send(msg)

if __name__ == '__main__':
    server = TCPServer(('', 5000), EchoHandler)
    server.serve_forever()

Client side

from socket import socket, AF_INET, SOCK_STREAM
sock = socket(AF_INET, SOCK_STREAM)
sock.connect(('localhost', 5000))
sock.send(b'Monty Python')
sock.recv(8192)  # returns b'Monty Python'

socketserver makes it relatively easy to create simple TCP servers. However, you should be aware that, by default, the servers are single threaded and can only serve one client at a time. If you want to handle multiple clients, either instantiate a ThreadingTCPServer instead.

from socketserver import ThreadingTCPServer
...
if __name__ == '__main__':
    server = ThreadingTCPServer(('', 5000), EchoHandler)
    server.serve_forever()

Creating a UDP Server

A UDP server is easily created using the socketserver library.

a simple time server:

import time
from socketserver import BaseRequestHandler, UDPServer

class CtimeHandler(BaseRequestHandler):
    def handle(self):
    print('connection from: ', self.client_address)
    # Get message and client socket
    msg, sock = self.request
    resp = time.ctime()
    sock.sendto(resp.encode('ascii'), self.client_address)

if __name__ == '__main__':
    server = UDPServer(('', 5000), CtimeHandler)
    server.serve_forever()

Testing:

>>> from socket import socket, AF_INET, SOCK_DGRAM
>>> sock = socket(AF_INET, SOCK_DGRAM)
>>> sick.sendto(b'', ('localhost', 5000))
0
>>> sock.recvfrom(8192)
(b'Wed Aug 15 20:35:08 2012', ('127.0.0.1', 5000))

Remarks#

The simplest Python socket client-server example

Creating a Simple Http Server

Creating a TCP server

Creating a UDP Server

Start Simple HttpServer in a thread and open the browser