udp-based socket of network programming (socket) socket

udp-based network programming

　　Features: No need to establish a link in advance, you need to obtain ip and port every time you send and receive

　　　　　Also known as the datagram protocol, one send corresponds to one receive, and there will be no sticky packet problem

　　　　   Unreliable transmission, sending data does not need to reply ACK confirmation information

　　　　   There is no link, the startup of the server or client does not need to be sequential

　　

udp server socket

1 ss = socket()    #Create a server socket 
2 ss.bind() #Bind        the server socket 
3 inf_loop: #Server        infinite loop 
4 cs = ss.recvfrom()/ss.sendto( ) #Dialogue (receive and send) 
5 ss.close()        

 

socket for udp client

cs = socket()    #Create a client socket 
comm_loop: #Communication       loop cs.sendto 
    ()/cs.recvfrom() #Dialogue    ( send/receive) 
cs.close() #Close                       the client socket

 

 

sample code

Socket communication based on UDP protocol

import socket

server = socket.socket (socket.AF_INET, socket.SOXK_DGRAM)

server.bind(('127.0.0.1',8080))

while True:
    client_data,client_addr=server.recvfrom(1024)
    server.sendto(client_data.upper(),client_addr)

Server

import socket

client = socket.socket (socket.AF_INET, socket.SOCK_DGRAM)

while True:
    msg = input('    : ' ).strip()
    client.sendto(msg.encode('utf-8'),('127.0.0.1',8080))
    res,server_addr =  client.recvfrom(1024)

client

 

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Common port: web port 80

　　　　　　dns port 53

　　　　　　dhcp port 67