使用python的socket模块进行网络编程

使用socket编程可以分成基于tcp和基于udp，tcp和udp两者最主要的区别是有无面向连接。

基于tcp的socket流程：

基于udp的socket的流程图：

（以上两图来源于网络）

可以看到基于udp的socket要简单得多，udp的客户端不需要事先connect，而udp的服务器端也不需要listen和accept。

下面贴上一些tcp client, tcp server, udp client, udp server的简单实现代码

tcp client:

__author__ = 'seven'
import socket

target_host = "127.0.0.1"
target_port = 80

client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect((target_host, target_port))
client.send("ABCDEF")
response = client.recv(4096)

print response
client.close()

tcp server:

__author__ = 'seven'
import socket
import threading

bind_ip = "0.0.0.0"
bind_port = 80

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind((bind_ip, bind_port))
server.listen(5)
print "[*] Listening on %s:%d" % (bind_ip, bind_port)

def handle_client(client_socket):
    request = client_socket.recv(1024)
    print "[*] Received: %s" % request
    client_socket.send("ACK!")
    client_socket.close()

while True:
    client, addr = server.accept()
    print "[*] Accepted connection from: %s:%d" % (addr[0], addr[1])
    client_handler = threading.Thread(target=handle_client, args=(client,))
    client_handler.start()

server.close()

udp client:

__author__ = 'seven'
import socket

target_host = "127.0.0.1"
target_port = 80

client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
client.sendto("ABCDEF", (target_host, target_port))
data, addr = client.recvfrom(4096)

print data
client.close()

udp server:

__author__ = 'seven'
import socket

bind_ip = "0.0.0.0"
bind_port = 80

server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
server.bind((bind_ip, bind_port))

while True:
    data, addr = server.recvfrom(4096)
    if not data:
        print "client has exist"
        break
    server.sendto("ACK!", addr)
    print "received:%s from %s" % (data, addr)

server.close()

稍微解释一下一些参数:

AF_INET参数说明使用标准的IPv4地址或主机名

AF_INET6参数说明使用IPv6地址或主机名

SOCK_STREAM参数说明是一个TCP客户端

SOCK_DGRAM参数说明是一个UDP客户端