python网络编程：一、前言及socket初探

懂ni

在知乎上看到有人提问，Python 网络编程需要学习哪些网络相关的知识？，看了下，觉得还挺有道理。主要的观点如下：





Python网络编程是一个很大的范畴，个人感觉需要掌握的点有：

• 如何使用Python来创建socket, 如何将socket与指定的IP地址和端口进行绑定，使用socket来发送数据，接受数据，
  
• 如何使用Python中处理线程，从而编写可以同时处理多个请求的web服务器
  
• 如何使用Python来控制HTTP层的逻辑，包括如何创建http GET,POST,PUT,DELETE请求，如何处理接受到的HTTP请求，这些分别涉及python的httplib, basehttpserver等模块
  
• 掌握一种基本的python的web开发框架，比如webpy, django,pylon
  
• 了解非阻塞式的HTTP Server,比如tornado
  
• 了解twisted, python编写的消息驱动的网络引擎
  

参考资料:

网络基础知识

• HTTP: the definitive guide http://www.amazon.com/HTTP-Definitive-Guide-David-Gourley/dp/1565925092/
  
• Computer Networking: A Top-Down Approach http://www.amazon.com/Computer-Networking-Top-Down-Approach-Edition/dp/0136079679/ref
  

python 网络编程基础         

• python 网络编程 http://www.amazon.com/Foundations-Python-Network-Programming-Goerzen/dp/1590593715
  
• python socket编程的文档 http://docs.python.org/library/socket.html
  
• python httplib的文档 http://docs.python.org/library/httplib.html
  

python常用框架文档:         

• django 的官方网站 https://www.djangoproject.com/
  
• twisted 的官方网站 http://twistedmatrix.com/trac/
  
• tornado 的官方网站 http://www.tornadoweb.org/
  

学了一下python的socket



socket概念：

      通常也称作"套接字"，用于描述IP地址和端口，是一个通信链的句柄。在Internet上的主机一般运行了多个服务软件，同时提供几种服务。每种服务都打开一个Socket，并绑定到一个端口上，不同的端口对应于不同的服务。Socket正如其英文原意那样，象一个多孔插座。一台主机犹如布满各种插座的房间，每个插座有一个编号，有的插座提供220伏交流电， 有的提供110伏交流电，有的则提供有线电视节目。 客户软件将插头插到不同编号的插座，就可以得到不同的服务。



主要用到的模块： socket

• 建立新的socket：socket.socket([family[, type[, proto]]])
  
• 获取远程服务器ip：socket.gethostbyname(host)
  
• 连接到一个远程套接字地址：socket.connect(address)
  
• 向socket发送数据：socket.sendall(string[, flags])
  
• 从socket接受数据：socket.recv(bufsize[, flags])
  

• Bind the socket to address.： socket.bind(address)
  
• Listen for connections made to the socket. ：socket.listen(backlog)
  

以下代码主要参考这个教程：http://www.binarytides.com/python-socket-programming-tutorial/

客户端：

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1 # clientsocket.py
2
3 import socket
4
5 def Main():
6     try:
7         # Address Family : AF_INET (this is IP version 4 or IPv4)
8         # Type :  SOCK_STREAM (this means connection oriented TCP protocol)
9         #         SOCK_DGRAM indicates the UDP protocol.
10         new_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
11     except socket.error, msg:
12         print 'Failed to creat socket. Error code:', str(msg[0]),
13         print 'Error message:', msg[1]
14         return
15     print 'Socket Created'
16     
17     host = 'www.baidu.com'
18     port = 80
19     try:
20         remote_ip = socket.gethostbyname(host)
21     except socket.gaierror:
22         print 'Hostname could not be resolved. Exiting.'
23         return
24     print 'Ip address of', host, 'is', remote_ip
25     
26     # Connect to remote server
27     new_socket.connect((host, port))
28     print 'Socket Connected to', host, 'on ip', remote_ip
29     
30     # Send some data to remote server | socket.sendall(string[, flags])
31     message = 'GET / HTTP/1.1\r\n\r\n'
32     try:
33         new_socket.sendall(message)
34     except socket.error:
35         print 'Send fail.'
36         return
37     print 'Message send successfully.'
38
39     # Receive data | socket.recv(bufsize[, flags])
40     reply = new_socket.recv(4096)
41     print reply
42     
43     # Close the socket
44     new_socket.close()
45     
46     
47 if __name__ == '__main__':
48     Main()
　　


服务器端：

• Bind the socket to address.： socket.bind(address)
  
• Listen for connections made to the socket. ：socket.listen(backlog)
  

#! /usr/bin/env python
# serversockethand.py
"""
To handle every connection we need a separate handling code to run along
with the main server accepting connections. One way to achieve this is
using threads. The main server program accepts a connection and creates
a new thread to handle communication for the connection, and then the
server goes back to accept more connections.
"""
import socket
import thread
def Main():
HOST = ''
PORT = 8888
new_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print 'Socket created.'
# Bind socket to local host and port
try:
new_socket.bind((HOST, PORT))
except socket.error, msg:
print 'Bind failed. Error code:', str(msg[0]) + 'Message' + msg[1]
return
print 'Socket bind complete'
# Listening on socket
new_socket.listen(10)
print 'Socket now listening..'
# Now keep talking with client
while 1:
# Wait to accept a connection
conn, addr = new_socket.accept()
print 'Connected with', addr[0], ':', str(addr[1])
thread.start_new_thread(clientThread, (conn, ))
new_socket.close()

# Function for handling connections. This will be used to create threads.
def clientThread(conn):
# Sending message to connected client
conn.send('Welcome to the server. Type something and hit enter\n')
while 1:
data = conn.recv(1024)
if not data:
break
reply = 'OK..' + data
conn.sendall(reply)
conn.close()

if __name__ == '__main__':
Main()
　　


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