2.7 套接字编程

互联网应用程序使用的协议分为两种：

• 实现在协议标准中的协议

• 专用的网络应用程序，使用的协议不公开

每一个进程可以拥有一至多个套接字，系统通过端口号（Port Number）标识套接字。

2.7.1 UDP套接字编程

客户端脚本：

from socket import *

# server_name为服务进程所在主机ip
server_name = 'hostname'
server_port = 12000

# SOCK_DGRAM 指明套接字使用UDP传输
client_socket = socket(AF_INET, SOCK_DGRAM)

message = 'keshuai'

client_socket.sendto(message, (server_name, server_port))

modified_message, server_address = client_socket.recvfrom(2048)

print modified_message

client_socket.close()

服务端脚本：

from socket import *

server_port = 12000
server_socket = socket(AF_INET, SOCK_DGRAM)
server_socket.bind(('', server_port))

print "The server is ready to receive"

while True:
    message, client_address = server_socket.recvfrom(2048)
    print "Recieve: %s" % message
    modified_message = message.upper()
    server_socket.sendto(modified_message, client_address)

2.7.2 TCP套接字编程

特殊的套接字实现TCP三次握手：

客户端脚本：

from socket import *

server_name = '172.23.83.57'
server_port = 12000

# SOCK_STREAM指明套接字使用TCP传输
client_socket = socket(AF_INET, SOCK_STREAM)

client_socket.connect((server_name, server_port))

message = 'keshuai'

client_socket.send(message)

modified_message = client_socket.recv(2048)

print modified_message

client_socket.close()

服务端脚本：

from socket import *

server_port = 12000
server_socket = socket(AF_INET, SOCK_STREAM)
server_socket.bind(('', server_port))
server_socket.listen(1)

print "The server is ready to receive"

while True:
    connection_socket, client_address = server_socket.accept()

    message = connection_socket.recv(2048)
    print "Recieve: %s" % message
    modified_message = message.upper()

    connection_socket.send(modified_message)

    connection_socket.close()