基于tcp的套接字，关键就是两个循环，一个链接循环，一个通信循环

socketserver模块中分两大类：server类（解决链接问题）和request类（解决通信问题）

server类：

request类：

继承关系:

查找属性的顺序：ThreadingTCPServer->ThreadingMixIn->TCPServer->BaseServer

1. 实例化得到ftpserver，先找类ThreadingTCPServer的__init__,在TCPServer中找到，进而执行server_bind,server_active
2. 找ftpserver下的serve_forever,在BaseServer中找到，进而执行self._handle_request_noblock()，该方法同样是在BaseServer中
3. 执行self._handle_request_noblock()进而执行request, client_address = self.get_request()（就是TCPServer中的self.socket.accept()），然后执行self.process_request(request, client_address)
4. 在ThreadingMixIn中找到process_request，开启多线程应对并发，进而执行process_request_thread，执行self.finish_request(request, client_address)
5. 上述四部分完成了链接循环，本部分开始进入处理通讯部分，在BaseServer中找到finish_request,触发我们自己定义的类的实例化，去找__init__方法，而我们自己定义的类没有该方法，则去它的父类也就是BaseRequestHandler中

源码分析总结：

基于tcp的socketserver我们自己定义的类中的

1. 　　self.server即套接字对象
2. 　　self.request即一个链接
3. 　　self.client_address即客户端地址

基于udp的socketserver我们自己定义的类中的

1. 　　self.request是一个元组（第一个元素是客户端发来的数据，第二部分是服务端的udp套接字对象），如(b'adsf', <socket.socket fd=200, family=AddressFamily.AF_INET, type=SocketKind.SOCK_DGRAM, proto=0, laddr=('127.0.0.1', 8080)>)
2. 　　self.client_address即客户端地址

 

import socketserverimport structimport jsonimport osclass FtpServer(socketserver.BaseRequestHandler):    coding='utf-8'    server_dir='file_upload'    max_packet_size=1024    BASE_DIR=os.path.dirname(os.path.abspath(__file__))    def handle(self):        print(self.request)        while True:            data=self.request.recv(4)            data_len=struct.unpack('i',data)[0]            head_json=self.request.recv(data_len).decode(self.coding)            head_dic=json.loads(head_json)            # print(head_dic)            cmd=head_dic['cmd']            if hasattr(self,cmd):                func=getattr(self,cmd)                func(head_dic)    def put(self,args):        file_path = os.path.normpath(os.path.join(            self.BASE_DIR,            self.server_dir,            args['filename']        ))        filesize = args['filesize']        recv_size = 0        print('----->', file_path)        with open(file_path, 'wb') as f:            while recv_size < filesize:                recv_data = self.request.recv(self.max_packet_size)                f.write(recv_data)                recv_size += len(recv_data)                print('recvsize:%s filesize:%s' % (recv_size, filesize))ftpserver=socketserver.ThreadingTCPServer(('127.0.0.1',8080),FtpServer)ftpserver.serve_forever()FtpServer

import socketimport structimport jsonimport osclass MYTCPClient:    address_family = socket.AF_INET    socket_type = socket.SOCK_STREAM    allow_reuse_address = False    max_packet_size = 8192    coding='utf-8'    request_queue_size = 5    def __init__(self, server_address, connect=True):        self.server_address=server_address        self.socket = socket.socket(self.address_family,                                    self.socket_type)        if connect:            try:                self.client_connect()            except:                self.client_close()                raise    def client_connect(self):        self.socket.connect(self.server_address)    def client_close(self):        self.socket.close()    def run(self):        while True:            inp=input(">>: ").strip()            if not inp:continue            l=inp.split()            cmd=l[0]            if hasattr(self,cmd):                func=getattr(self,cmd)                func(l)    def put(self,args):        cmd=args[0]        filename=args[1]        if not os.path.isfile(filename):            print('file:%s is not exists' %filename)            return        else:            filesize=os.path.getsize(filename)        head_dic={
   'cmd':cmd,'filename':os.path.basename(filename),'filesize':filesize}        print(head_dic)        head_json=json.dumps(head_dic)        head_json_bytes=bytes(head_json,encoding=self.coding)        head_struct=struct.pack('i',len(head_json_bytes))        self.socket.send(head_struct)        self.socket.send(head_json_bytes)        send_size=0        with open(filename,'rb') as f:            for line in f:                self.socket.send(line)                send_size+=len(line)                print(send_size)            else:                print('upload successful')client=MYTCPClient(('127.0.0.1',8080))client.run()FtpClient