如何在 python 中处理 UDP 套接字客户端

Question

在 TCP 套接字中，您绑定然后通过 s.accept() 接受连接，但在 UDP 套接字中，您只需绑定服务器和任何人连接（如果我错了，请纠正我）所以如何控制客户端，例如，如果 5 个客户端连接到服务器关闭服务器，或者如果有人连接到服务器，向他发送一条消息，说欢迎使用服务器 感谢您的任何回答。

Answer 1

根据定义，UDP 没有“会话”的概念，因此它不知道它当前正在处理多少。

您需要在代码中实现某种会话管理，以决定客户端何时处于活动状态或不处于活动状态，并对此采取行动。

下面的示例代码部分应允许最多五个客户端并在 30 秒后使它们过期。

bind_ip = '192.168.0.1' ## The IP address to bind to, 0.0.0.0 for all
bind_port = 55555 ## The port to bind to
timeout = 30 ## How long before forgetting a client (seconds)
maximum = 5 ## Maximum number of clients

###
import socket
import time

## Create the socket as an internet (INET) and UDP (DGRAM) socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

## Bind to the server address and port
sock.bind((bind_ip, bind_port))

## Make a dict to store when each client contacted us last
clients = dict()

## Now loop forever
while True:
    ## Get the data and the address
    data, address = sock.recvfrom(1024)

    ## Check timeout of all of the clients
    for addr in clients.keys():
        ## See if the timeout has passed
        if clients[addr] < (time.time() - timeout):
            ## Expire the client
            print('Nothing from ' + addr + ' for a while. Kicking them off.')           
            clients.pop(addr)

    ## Check if there are too many clients and if we know this client
    if len(clients.keys()) > maximum and address not in clients.keys():
        print('There are too many clients connected!')
        continue    

    ## Update the last contact time
    clients[address] = time.time()

    ## Do something with the data
    print('Received from ' + str(address) + ': ' + str(data))           

这绝不是最有效的方法，仅作为示例。

相关阅读：https://en.wikibooks.org/wiki/Communication_Networks/TCP_and_UDP_Protocols/UDP