python网络编程——简单例子

rrt44

客户端（client.py）



import socket
import sys
port = 70
host = sys.argv[1]
filename = sys.argv[2]
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect((host, port))
fd = s.makefile("rw", 0)
fd.write(filename + "\n")
for line in fd.readlines():
sys.stdout.write(line)
　　程序通过socket.socket()建立一个Socket，参数告诉系统需要一个Internet Socket进行TCP通信。接着程序链接远程的主机名，并提供文件名。最后获得响应后在屏幕上打印出来。
　　测试



python client.py quux.org /

　　显示



iWelcome to gopher at quux.org!fake(NULL)0
ifake(NULL)0
iThis server has a lot of information of historic interest,fake(NULL)0
ifunny, or just plain entertaining -- all presented in Gopher.fake(NULL)0
iThere are many mirrors here of rare or valuable files with thefake(NULL)0
iaim to preserve them in case their host disappears.  PLEASE READfake(NULL)0
i"About This Server" FOR IMPORTANT NOTES AND LEGAL INFORMATION.fake(NULL)0
ifake(NULL)0
0About This Server/About This Server.txtgopher.quux.org70+
1Archives/Archivesgopher.quux.org70+
1Books/Booksgopher.quux.org70+
1Communication/Communicationgopher.quux.org70+
iThis directory contains the entire text of the bookfake(NULL)0
i"We the Media: Grassroots Journalism by the People, for the People"fake(NULL)0
iby Dan Gillmor in various formats.fake(NULL)0
ifake(NULL)0
iFeel free to download and enjoy.fake(NULL)0
1Computers/Computersgopher.quux.org70+
1Current Issues and Events (Updated Apr. 23, 2002)/Currentgopher.quux.org70+
1Development Projects/develgopher.quux.org70+
0Gopher's 10th Anniversary/3.0.0.txtgopher.quux.org70
1Government, Politics, Law, and Conflict/Governmentgopher.quux.org70+
0How To Help/How To Help.txtgopher.quux.org70+
1Humor and Fun/Humor and Fungopher.quux.org70+
1Index to Quux.Org/Archives/indexgopher.quux.org70
1Internet/Internetgopher.quux.org70+
1Other Gopher Servers/Software/Gopher/serversgopher.quux.org70
1People/Peoplegopher.quux.org70+
1Reference/Referencegopher.quux.org70+
1Software and Downloads/Softwaregopher.quux.org70+
1The Gopher Project/Software/Gophergopher.quux.org70
0What's New/whatsnew.txtgopher.quux.org70+　
服务端（server.py）



# coding: utf-8
import socket
host = ''
port = 51421
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((host, port))
s.listen(1)               #每次最多只有一个等候处理
print "Server is running on port %d; press Ctrl-C to terminate." %port

while 1:
clientsock, clientaddr = s.accept()
clientfile = clientsock.makefile('rw', 0)
clientfile.write("Welcome, " + str(clientaddr) + "\n")
clientfile.write("Please enter a string: ")
line = clientfile.readline().strip()
clientfile.write("You entered %d characters. \n" %len(line))
clientfile.close()
clientsock.close()
　　建立一个socket，设置成可复用的（reusable），绑定端口号51421（可选大于1024的任一值），调用listen（）函数，开始等待来自客户端的请求，同时设定最多只有一个等候处理的链接。
　　主循环对a.accept（）函数调用开始，程序连接一个客户端后立马停止，接收用户的输入。
　　运行一个例子
　　首先运行server.py



python server.py

　　另开一个终端，连接localhost的51421端口。　



jihite@ubuntu:~/web$ telnet localhost 51421
Trying 127.0.0.1...
Connected to localhost.
Escape character is '^]'.
Welcome, ('127.0.0.1', 59853)
Please enter a string: mm
You entered 2 characters.
Connection closed by foreign host.