Application Scenario
Inter-process communication across networks, with connection and reliable transmission.
TCP-Based Socket Communication Process
TCP Server TCP Client
1、socket() 1、socket()
2、bind()
3、listen()
4、accept() <———————– 2、connect()
5、recv() <———————— 3、send()
6、send() ————————-> 4、recv()
7、close() 5、close()
Description:
socket(): Create a socket.
bind(): The server binds the IP and port,called only by the server.
listen(): The server starts listening for client connection requests,called only by the server.
accept(): The server blocks and waits for a client connection,called only by the server.
connect(): The client connects to the server,called only by the client.
send() / sendall(): Send byte data.
recv(): Block and receive data.
close(): Close the connection and the socket.The client calls close(), and the server will receive empty data, indicating that the client has disconnected.
Server Example Code
import socket
HOST = '127.0.0.1'
PORT = 5000
# Create socket
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Bind address and port
server.bind((HOST, PORT))
# Start listening, ready to accept client requests
server.listen()
print("Server started, waiting for client connection...")
# Block and wait for client connection
conn, addr = server.accept()
print("Client connected:", addr)
while True:
data = conn.recv(1024)
if not data:
print("Client disconnected")
break
print("Client sent content:", data.decode())
# Send message back to client
conn.sendall(b"Server received: " + data)
conn.close()
server.close()Client Example Code
import socket
HOST = '127.0.0.1'
PORT = 5000
# Create socket
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# Connect to server
client.connect((HOST, PORT))
while True:
msg = input("Enter the message to send:")
if msg == "quit":
break
client.sendall(msg.encode())
# Receive server reply
data = client.recv(1024)
print("Server reply content:", data.decode())
client.close()Verification
1、Start the server.
python tcp_server.py
2、Start the client.
python tcp_client.py
3、The client inputs data and checks the printout.
Sequentially input 1, 100, hello, this is a test.
The client terminal prints as follows:
Enter the message to send: 1
Server reply content: Server received: 1
Enter the message to send: 100
Server reply content: Server received: 100
Enter the message to send: hello
Server reply content: Server received: hello
Enter the message to send: this is a test
Server reply content: Server received: this is a test
4、The server receives data and checks the printout.
The server terminal prints as follows:
Server started, waiting for client connection…
Client connected: (‘127.0.0.1’, 14297)
Client sent content: 1
Client sent content: 100
Client sent content: hello
Client sent content: this is a test
5、The client inputs “quit” to exit the program.