Python socketserver模块解析

Posted 2021-01-23 朝花夕拾

参考：https://blog.csdn.net/qq_33733970/article/details/79153938

1.功能简介

• socketserver模块是对socket模块的再封装，用于简化网络服务器的编写，并且实现了多用户的在线，即多并发

2.功能分类

#处理链路问题server类
        +------------+
        | BaseServer |
        +------------+
              |
              v
        +-----------+        +------------------+
        | TCPServer |------->| UnixStreamServer |
        +-----------+        +------------------+
              |
              v
        +-----------+        +--------------------+
        | UDPServer |------->| UnixDatagramServer |
        +-----------+        +--------------------+
　　
   #处理多线程并发:
　　"ThreadingMixIn","ThreadingUDPServer","ThreadingTCPServer"
　　#处理多进程并发:
　　"ForkingUDPServer","ForkingTCPServer", "ForkingMixIn"

#处理通信问题request类
　　"BaseRequestHandler", "StreamRequestHandler","DatagramRequestHandler"

3.类继承关系

●处理多线程并发相关类继承关系

threading-inherit-relation

●处理多进程并发相关类继承关系

forking-inherit-relation

●处理通信request相关类继承关系

request-inherit-relation

 4.如何创建socketserver服务

①创建一个请求处理类（FtpServer），继承BaseRequestHandler类，并重写父类handle()方法；
②实例化服务器类（TCPServer、UDPServer、UnixStreamServer或UnixDatagramServer），传入（IP, 端口）及定制的请求处理类（FtpServer）；
③server.handle_requese() #只处理一个请求
④server.server_forever() #处理多个请求
⑤server.server_close()   #关闭socket

5.基于TCP协议实现的FTPServer服务调用过程解析

import socketserver

class FtpServer(socketserver.BaseRequestHandler):
    def handle(self):
        pass

ftpserver = socketserver.ThreadingTCPServer((\'127.0.0.1\', 8080), FtpServer)

ftpserver.serve_forever()

1.属性解析顺序

ThreadingTCPServer-->ThreadingMixIn-->TCPServer-->BaseServer

2.调用TCPSever类的__init__方法获取实例化对象

class TCPServer(BaseServer):
    def __init__(self, server_address, RequestHandlerClass, bind_and_activate=True):
        self.server_bind()
        self.server_activate()

3.调用BaseServer类的server_forever方法，并处理请求

class BaseServer:
    def serve_forever(self, poll_interval=0.5):
        self._handle_request_noblock()

    def _handle_request_noblock(self):
        """相当于TCPServer中的self.socket.accept()"""
        request, client_address = self.get_request()
        """接收请求，并处理来次客户端的请求"""
        self.process_request(request, client_address)

4.调用ThreadingMixIn类的process_request方法，执行process_request_thread方法

class ThreadingMixIn:
    def process_request_thread(self, request, client_address):
        self.finish_request(request, client_address)

    def process_request(self, request, client_address):
        """开启新线程处理请求"""
        t = threading.Thread(target = self.process_request_thread, args = (request, client_address))
        t.daemon = self.daemon_threads
        t.start()

5.调用BaseServer类的finish_request方法，完成请求，至此链接循环的处理完成，开始通讯循环

def finish_request(self, request, client_address):
    """通过实例化定制类（FtpServer）去结束一个请求"""
    self.RequestHandlerClass(request, client_address, self)

6.调用BaseRequestHandler类的__init__方法

class BaseRequestHandler:
    def __init__(self, request, client_address, server):
        """
　　　　　调用了对象自己的handle()方法
　　　　　服务端跟客户端所有的交互都在重写的handle()方法中
　　　　　"""
        self.handle()