Networking Basics: socket module

socket：

　　Socket (Socket) is an abstraction layer, the application can send or receive data through it, can be the same as file open, close, and write operations. Sockets allow an application I / O into the network, and communicate with other applications in the network. Network socket is a combination of IP addresses and ports.

Socket TCP-based protocol: tcp is based on the link, you must first start the server, and then start the client to the server links

server server:

# Server server 
Import socket 
SK = socket.socket () # create a service socket 
sk.bind (( ' 127.0.0.1 ' , 8080))   # to bind to a socket address 
sk.listen ()              # establish listening link, can function to accept the requirement for inspection 
Conn, addr = sk.accept () # receiving client link, receiving values of the object and the client socket address information 
ret = conn.recv (1024) .decode ( ' UTF-. 8 ' )    # receiving the client message 
Print (RET)               # print client message 
conn.send (bytes ( ' Hello ' , encoding = ' UTF-. 8 ' ))# Using the received client sends a message to the client socket 
conn.Close ()             # close client socket 
sk.close ()               # close the server socket (optional)

client client:

Import socket 
SK = socket.socket ()             # create client socket 
sk.connect (( ' 127.0.0.1 ' , 8080))   # attempt to connect to the server 
sk.send (bytes ( ' Nice to meet you ' , encoding = ' UTF -8 ' )) # send message 
RET = sk.recv (1024) .decode ( ' UTF-. 8 ' )      # receiving message 
Print (RET)                       # Print message 
sk.close ()                       # close the client socket

Note: Accept the server receives a connection request of a client, the client returns a new socket object, and an address information, a new socket for the UE to receive or transmit messages. Binding address with the server to bind a socket, and connect the client with the server.

 

Test 1:

# Pretending chat 
# Server: 
Import Socket 
SK = socket.socket () 
sk.bind (( ' 127.0.0.1 ' , 8081 )) 
sk.listen () 
Conn, addr = sk.accept ()
 the while True: 
    RET = Conn .recv (1024) .decode ( ' UTF-. 8 ' )
     Print (RET)
     IF RET == ' Cool: BYE ' : 
        conn.send (bytes ( ' You You grapefruit Cech trouble: BYE ' , encoding = ' UTF- 8 ' ))
        break
    info = input('柚柚柚切克闹：')
    conn.send(bytes('柚柚柚切克闹：%s'%(info),encoding='utf-8'))
conn.close()
sk.close()


#client：
import socket
sk = socket.socket()
sk.connect(('127.0.0.1',8081))
while True:
    chat = input('cool：')
    sk.send(bytes('cool：%s'%(chat),encoding='utf-8'))
    ret = sk.recv(1024).decode('utf-8')
    print(ret)
    if ret == '柚柚柚切克闹：bye':
        sk.send(bytes('cool：bye',encoding='utf-8'))
        break

sk.close()

Test 2:

　　Every ten seconds the UE sends a timestamp, a format returns to the client the server after the server receives the time

#server：
import socket,time
sk = socket.socket()
sk.bind(('127.0.0.1',8081))
sk.listen()
conn,addr = sk.accept()
while True:
    ret = conn.recv(1024).decode('utf-8')
    print(ret)
    info_ret = time.strftime('%Y-%m-%d %H:%M:%S', time.localtime(int(ret))) #需要把字符串强转为整型
    conn.send(bytes(str(info_ret),encoding='utf-8'))
conn.Close () 
sk.close () 

# Client 
Import Socket, Time 
SK = socket.socket () 
sk.connect (( ' 127.0.0.1 ' , 8081 ))
 the while True: 
    the time.sleep ( 10 ) 
    Timer = int ( the time.time ()) # stamp value returned float, to be converted into an integer 
    sk.send (bytes (STR (Timer), encoding = ' UTF-. 8 ' )) # can only pass bytes type of the transmitted message is a string 
    RET = sk.recv (1024) .decode ( ' UTF-. 8 ' )
     Print (RET) 

sk.close ()

 Note: transmission of a message is a string note convert between data types