并发编程之socketserver模块

一、socketserver模块介绍

基于tcp套接字，关键的就是两个循环，一个是链接循环，一个是通信循环

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

以下述代码为例，分析socketserver源码：

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

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中找....

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

二、socketserver应用

 import socketserver
 class MyTCPhandle(socketserver.BaseRequestHandler):  #必须继承socketserver.BaseRequestHandler这个类
     def handle(self): #必须要实现一个handle方法
         # print(self.request)  #self.request相当于conn
         # print(self.client_address)  #('127.0.0.1', 51393)  self.client_address相当于addr
         while True:
             try:
                 data = self.request.recv(1024)  #IO操作
                 self.request.send(data.upper())
             except Exception:
                 break
         self.request.close()
 if __name__ == '__main__':
         server = socketserver.ThreadingTCPServer(('127.0.0.1',8080),MyTCPhandle) #开启线程。accept方法也包括了
         server.allow_reuse_address = True  #默认为False，设为True,相当于 server.setsockopt(SOL_SOCKET,SO_REUSEADDR,1) 重用地址
         server.serve_forever() #一直开启，相当于我们以前做的链接循环

服务端

 from socket import *
 client  = socket(AF_INET,SOCK_STREAM)
 client.connect(('127.0.0.1',8080))
 while True:
     cmd = input('>>:').strip()
     if not cmd:continue
     client.send(cmd.encode('utf-8'))
     data = client.recv(1024)
     print('接受的是：%s'%data.decode('utf-8'))
 client.close()

客户端

三、上传下载文件（这里只是上传）

 import socket
 import struct
 import json
 import subprocess
 import os

 class MYTCPServer:
     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
     server_dir='file_upload'
     def __init__(self, server_address, bind_and_activate=True):
         self.server_address=server_address
         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

     def server_bind(self):
         if self.allow_reuse_address:
             self.socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
         self.socket.bind(self.server_address)
         self.server_address = self.socket.getsockname()

     def server_activate(self):
         self.socket.listen(self.request_queue_size)

     def server_close(self):
         self.socket.close()

     def get_request(self):
         return self.socket.accept()

     def close_request(self, request):
         request.close()

     def run(self):
         while True:
             self.conn,self.client_addr=self.get_request()
             print('from client ',self.client_addr)
             while True:
                 try:
                     head_struct = self.conn.recv(4)
                     if not head_struct:break

                     head_len = struct.unpack('i', head_struct)[0]
                     head_json = self.conn.recv(head_len).decode(self.coding)
                     head_dic = json.loads(head_json)

                     print(head_dic)
                     #head_dic={'cmd':'put','filename':'a.txt','filesize':123123}
                     cmd=head_dic['cmd']
                     if hasattr(self,cmd):
                         func=getattr(self,cmd)
                         func(head_dic)
                 except Exception:
                     break

     def put(self,args):
         file_path=os.path.normpath(os.path.join(
             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.conn.recv(self.max_packet_size)
                 f.write(recv_data)
                 recv_size+=len(recv_data)
                 print('recvsize:%s filesize:%s' %(recv_size,filesize))

 tcpserver1=MYTCPServer(('127.0.0.1',8080))

 tcpserver1.run()

服务端

 import socket
 import struct
 import json
 import os

 class 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()

客户端