TCP-based socket: Links cycle

# Server must meet at least three things: 
# 1 binds a fixed ip and Port 
# 2. external services has been stable operation 
# 3 can support concurrent 


#### this program can achieve functional cycle links, a an incoming provided semijoin pool size determines how many can come, a wait also come to a 


### server application 


from Socket Import * 

Server Socket = (AF_INET, SOCK_STREAM) 
server.bind (( '127.0 .0.1 ', 8081)) 
server.listen (. 5) 

# links circulating 
the while True: 
    Conn, client_addr = server.accept () 
    Print (client_addr) 

    # communications cycle 
    the while True: 
        the try: 
            Data = conn.recv (1024) 
            IF len (data) == 0: break # linux system for 
            print ( '-> receiving the client message:', Data) 
            conn.send (data.upper ()) 
        the except ConnectionResetError: 
            BREAK

    conn.close()

server.close()

##客户端程序

from socket import *

client = socket(AF_INET, SOCK_STREAM)
client.connect(('127.0.0.1', 8081))

# 通信循环
while True:
    msg=input('>>: ').strip() #msg=''
    if len(msg) == 0:continue
    client.send(msg.encode('utf-8')) #client.send(b'')
    # print('has send')
    data=client.recv(1024)
    # print('has recv')
    print(data)

client.close()