day8-socketserver使用2

问题简述

在上一个在实现socketserver实验中，我们尝试打开多个客户端连接到sockerserver，但是从第2个客户端发起的会话开始，都处于挂起状态，无法实现多用户多并发，那么，我们如何实现多并发呢？

并不是socketserver不支持多并发，而是到现在为止，还没有加入多并发的功能，上面的服务器端，我们只需要该一个代码就可以实现多并发。

多用户并发

多线程

用法：在实例化Server对象时，只需要使用ThreadingTCPServer多线程处理即可

import socketserver


class MyTCPHandler(socketserver.BaseRequestHandler):
    """
    服务器的请求处理类

    每次连接到服务器都会被实例化一次，并且必须重写handle()方法来实现与之通信的客户端
    """

    def handle(self):

        while True:
          try:
            # self.request 是TCP socket连接到客户端
            self.data = self.request.recv(1024).strip()
            print("{} wrote:".format(self.client_address[0]))
            print(self.data)
            if not self.data: #如果没有收到数据，说明客户端已断开
                print("客户端{}已经断开！".format(self.client_address[0]))
                break
            # 发回同样的数据，只是变成了大写
            self.request.send(self.data.upper())
          except ConnectionResetError as e:
              print("error",e)
              break

if __name__ == "__main__":
    HOST, PORT = "localhost", 9993

    # 创建一个Server对象并绑定IP地址和端口
    server = socketserver.ThreadingTCPServer((HOST,PORT), MyTCPHandler)  #ThreadingTCPServer多并发

    # 激活Server后，它将一直运行直到使用Ctrl-C去中断它
    server.serve_forever()

解析：每接收一个请求，服务器端就会开启一个新的独立的线程跟发来的客户端连接进行交互，

多进程

用法：在实例化Server对象时，只需要使用ForkingTCPServer多进程处理即可

import socketserver


class MyTCPHandler(socketserver.BaseRequestHandler):
    """
    服务器的请求处理类

    每次连接到服务器都会被实例化一次，并且必须重写handle()方法来实现与之通信的客户端
    """

    def handle(self):

        while True:
          try:
            # self.request 是TCP socket连接到客户端
            self.data = self.request.recv(1024).strip()
            print("{} wrote:".format(self.client_address[0]))
            print(self.data)
            if not self.data: #如果没有收到数据，说明客户端已断开
                print("客户端{}已经断开！".format(self.client_address[0]))
                break
            # 发回同样的数据，只是变成了大写
            self.request.send(self.data.upper())
          except ConnectionResetError as e:
              print("error",e)
              break

if __name__ == "__main__":
    HOST, PORT = "localhost", 9992

    # 创建一个Server对象并绑定IP地址和端口
    server = socketserver.ForkingTCPServer((HOST,PORT), MyTCPHandler)

    # 激活Server后，它将一直运行直到使用Ctrl-C去中断它
    server.serve_forever()

class socketserver.BaseServer(server_address,RequestHandlerClass)主要有以下方法:

class socketserver.BaseServer(server_address, RequestHandlerClass)
This is the superclass of all Server objects in the module. It defines the interface, given below, but does not implement most of the methods, which is done in subclasses. The two parameters are stored in the respective server_address and RequestHandlerClass attributes.
#TCPServer都继承BaseServer，下面是BaseServer下的几个方法

fileno() 文件描述符
Return an integer file descriptor for the socket on which the server is listening. This function is most commonly passed to selectors, to allow monitoring multiple servers in the same process.

handle_request() 处理单个请求
Process a single request. This function calls the following methods in order: get_request(), verify_request(), and process_request(). If the user-provided handle() method of the handler class raises an exception, the server’s handle_error() method will be called. If no request is received within timeout seconds, handle_timeout() will be called and handle_request() will return.

serve_forever(poll_interval=0.5)
Handle requests until an explicit明确的 shutdown() request. Poll检查 for shutdown every poll_interval seconds. Ignores the timeout attribute. It also calls service_actions(), which may be used by a subclass or mixin to provide actions specific to a given service. For example, the ForkingMixIn class uses service_actions() to clean up zombie僵尸 child processes.

Changed in version 3.3: Added service_actions call to the serve_forever method.

service_actions()
This is called in the serve_forever() loop. This method can be overridden by subclasses or mixin classes to perform actions specific to a given service, such as cleanup actions.

New in version 3.3.

shutdown()
Tell the serve_forever() loop to stop and wait until it does.

server_close()
Clean up the server. May be overridden.

address_family
The family of protocols to which the server’s socket belongs. Common examples are socket.AF_INET and socket.AF_UNIX.

RequestHandlerClass  请求处理类
The user-provided request handler class; an instance of this class is created for each request.

server_address
The address on which the server is listening. The format of addresses varies depending on the protocol family; see the documentation for the socket module for details. For Internet protocols, this is a tuple containing a string giving the address, and an integer port number: ('127.0.0.1', 80), for example.

socket
The socket object on which the server will listen for incoming requests.

The server classes support the following class variables:

allow_reuse_address 
Whether the server will allow the reuse of an address. This defaults to False, and can be set in subclasses to change the policy.

request_queue_size
The size of the request queue. If it takes a long time to process a single request, any requests that arrive while the server is busy are placed into a queue, up to request_queue_size requests. Once the queue is full, further requests from clients will get a “Connection denied” error. The default value is usually 5, but this can be overridden by subclasses.

socket_type
The type of socket used by the server; socket.SOCK_STREAM and socket.SOCK_DGRAM are two common values.

timeout
Timeout duration, measured in seconds, or None if no timeout is desired. If handle_request() receives no incoming requests within the timeout period, the handle_timeout() method is called.

There are various server methods that can be overridden by subclasses of base server classes like TCPServer; these methods aren’t useful to external users of the server object.

finish_request()
Actually processes the request by instantiating RequestHandlerClass and calling its handle() method.

get_request()
Must accept a request from the socket, and return a 2-tuple containing the new socket object to be used to communicate with the client, and the client’s address.

handle_error(request, client_address)
This function is called if the handle() method of a RequestHandlerClass instance raises an exception. The default action is to print the traceback to standard output and continue handling further requests.

handle_timeout()
This function is called when the timeout attribute has been set to a value other than None and the timeout period has passed with no requests being received. The default action for forking servers is to collect the status of any child processes that have exited, while in threading servers this method does nothing.



process_request(request, client_address)
Calls finish_request() to create an instance of the RequestHandlerClass. If desired, this function can create a new process or thread to handle the request; the ForkingMixIn and ThreadingMixIn classes do this.

server_activate()
Called by the server’s constructor to activate the server. The default behavior for a TCP server just invokes listen() on the server’s socket. May be overridden.

server_bind()
Called by the server’s constructor to bind the socket to the desired address. May be overridden.

verify_request(request, client_address)
Must return a Boolean value; if the value is True, the request will be processed, and if it’s False, the request will be denied. This function can be overridden to implement access controls for a server. The default implementation always returns True.

socketserver.BaseServer