Python_20180504

TCP/IP is a reliable transport protocol, UDP is unreliable Action at the fourth transport layer

Socket: Also known as "socket", it is used to describe ip address and port. It is a handle of a communication chain. Applications usually make requests to or respond to network requests through "sockets".

Socket originated from Unix, and one of the basic philosophies of Unix/Linux is that "everything is a file". Socket is an implementation of this mode. Socket is a special file, and some socket functions operate on it.

The socket module is for opening, reading, writing, and closing sockets on the server side and the client side.

 

socket_server：

#!/usr/bin/env python 
# encoding: utf-8 
import socket #socket is a standard library 
ip_port = ( '127.0.0.1' , 9999) 

sk = socket.socket() # should declare whether it is TCP/IP or UDP 
sk.bind(ip_port) # is a tuple 
sk.listen( 5) # The maximum number of connections allowed is 5. 

while True: 
 print( 'Server waiting...') 
conn ,addr = sk.accept() #Calling this method will return two values 
​​#conn is the instance created for the client, addr is the client's address 
client_data = conn. recv( 1024) #recv data print( str(client_data , 'utf8') ,) conn. sendall( bytes( 'Don't answer, don't answer, don't answer, don't answer!!' , 'utf8'))
 

 #Send data to the client 
conn.close()


 socket_client:
#!/usr/bin/env python
# encoding: utf-8
import socket
ip_port = ('127.0.0.1',9999)

sk = socket.socket()
sk. connect(ip_port)

sk.sendall(bytes('request to occupy the earth','utf8'))
server_reply = sk.recv(1024)
print(str(server_reply,'utf8'))

sk.close()