python socket server源码学习

原文请见：http://www.cnblogs.com/wupeiqi/articles/5040823.html

这里就是自己简单整理一下：

#!/usr/bin/env python
# -*- coding:utf-8 -*-
import SocketServer

class MyServer(SocketServer.BaseRequestHandler):

    def handle(self):
        # print self.request,self.client_address,self.server
        conn = self.request
        conn.sendall('欢迎致电 10086，请输入1xxx,0转人工服务.')
        Flag = True
        while Flag:
            data = conn.recv(1024)
            if data == 'exit':
                Flag = False
            elif data == '0':
                conn.sendall('通过可能会被录音.balabala一大推')
            else:
                conn.sendall('请重新输入.')

if __name__ == '__main__':
    server = SocketServer.ThreadingTCPServer(('127.0.0.1',8009),MyServer)
    server.serve_forever()

　程序先运行server的一个实例，socket.server.ThreadingTCPServer的构造方法，

server继承ThreadingMixIn, TCPServer这两个类，构造方法只有TCPServer的类有并且继承其父类BaseServer的构造方法。

TCPSever的构造方法（这个构造方法会执行bind和listen）：

    def __init__(self, server_address, RequestHandlerClass, bind_and_activate=True):
        """Constructor.  May be extended, do not override."""
        BaseServer.__init__(self, server_address, RequestHandlerClass)
        self.socket = socket.socket(self.address_family,
                                    self.socket_type)
        if bind_and_activate:
            try:
                self.server_bind()
                self.server_activate()
            except:
                self.server_close()
                raise

　　BaseServer的构造方法:

    def __init__(self, server_address, RequestHandlerClass):
        """Constructor.  May be extended, do not override."""
        self.server_address = server_address
        self.RequestHandlerClass = RequestHandlerClass
        self.__is_shut_down = threading.Event()
        self.__shutdown_request = False

　　在BaseServer中的构造方法中MyServer类赋给了实例的属性RequestHandlerClass ，相当于server实例有了这个属性。server实例创建完成。

然后是执行server的server_forever方法，

接下来就是BaseServer的server_forever方法->BaseServer的_handle_request_noblock方法->ThreadingMixIn的process_request方法（TCPServer和ThreadingMixIn都有这个方法，但ThreadingMixIn优先级高所以是ThreadMixIn的这个方法）->ThreadingMixIn的process_request_thread方法（这时候是多线程中的一个线程的具体处理方法了）

    def process_request_thread(self, request, client_address):
        """Same as in BaseServer but as a thread.

        In addition, exception handling is done here.

        """
        try:
            self.finish_request(request, client_address)
            self.shutdown_request(request)
        except:
            self.handle_error(request, client_address)
            self.shutdown_request(request)

　　->BaseServer的finish_request方法（调用实例的这个方法，这个方法ThreadMixIn中没有BaseServer中有，这时候会执行RequestHandlerClass的构造方法也就是我们写的MyServer的构造方法，但是MyServer中没有需要MyServer的父类中查找）

    def finish_request(self, request, client_address):
        """Finish one request by instantiating RequestHandlerClass."""
        self.RequestHandlerClass(request, client_address, self)

　　->BaseRequestHandler的构造方法

    def __init__(self, request, client_address, server):
        self.request = request
        self.client_address = client_address
        self.server = server
        self.setup()
        try:
            self.handle()
        finally:
            self.finish()

　　这上面finish，setup都是空的，handle是MyServer中定义的，这几个方法都需要我们自定义，

->MyServer的handle方法

->TcpServer的shutdown_request方法

->TcpServer的close_request方法

    def close_request(self, request):
        """Called to clean up an individual request."""
        request.close()

　　这里request一直是client端的socket，到这里就关闭socket了算是完成了一次处理。