socket

socket用于底层通信，常用于长连接。短连接底层也是基于socket.比如Http访问。
socket一般分为客户端和服务器端2个部分。

tcp

客户端

#!/usr/bin/env python3
#_*_encoding:utf-8_*_

import socket
def socket_client():
    #1 create socket
    s = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    #2 point host
    host = socket.gethostname()
    print(host)
    #3 point port
    port = 9999
    #4 connect
    s.connect((host,port))
    # once connected to server ,Server may send some message to client without client send request
    print(s.recv(1024).decode('utf-8'))
    #5 send message and recieve message
    for data in ['xiaomeng','xiaozhi','xiaoqiang']:
        s.send(data.encode('utf-8'))
        print(s.recv(1024).decode('utf-8'))
    s.send(b'exit')
    #7 close socket
    s.close()
    
def main():
    socket_client()
if __name__ == '__main__':
    main()

服务端

import socket

import threading
import time

def socket_server():
    server_socket = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
    host = socket.gethostname()
    port = 9999
    server_socket.bind((host,port))
    server_socket.listen(5)
    while True:
        sock,addr = server_socket.accept()
        t = threading.Thread(target=tcp_link,args=(sock,addr))
        t.start()
def tcp_link(sock,addr):
    print('accept',addr)
    sock.send('欢迎学习Python'.encode('utf-8'))
    while True:
        data = sock.recv(1024)
        #time.sleep(1)
        if not data or data.decode('utf-8') == 'exit':
            break
        sock.send(('hello.%s!' % data.decode('utf-8')).encode('utf-8'))
    sock.close()
    print('server receive connect close with',addr)
    
def main():
    socket_server()
if __name__ == '__main__':
    main()

UDP

没有TCP安全

客户端

#!/usr/bin/env python3
#_*_encoding:utf-8_*_

import socket
def socket_client():
    s = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
    host = socket.gethostname()
    port = 9999
    for i in ['aa','vv']:
        s.sendto(i.encode('utf-8'),(host,port))
        print(s.recv(1024).decode('utf-8'))
def main():
    socket_client()
if __name__ == '__main__':
    main()

服务端

import socket

import threading
import time

def socket_server():
    server_socket = socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
    host = socket.gethostname()
    port = 9999
    server_socket.bind((host,port))
    while True:
        data,addr = server_socket.recvfrom(1024)
        server_socket.sendto(b'hello %s' % data,addr) 
def main():
    socket_server()
if __name__ == '__main__':
    main()