仅当发送python套接字时才接收数据

Question

我正在使用python编写一个messenger应用程序，并且遇到问题。问题很简单：我希望程序只发送来自另一台计算机的数据，否则，我的程序会无限等待数据传输。我会如何编写这段代码？我想这会是这样的：

try: 
     data = s.recv(1024).decode() 
    except: 
     data == None 

Answer 1

见select模块。一个套接字可以通过超时进行监控，以便进行其他过程。

实例的服务器：

import socket 
import select 

with socket.socket() as server: 
    server.bind(('',5000)) 
    server.listen(3) 
    to_read = [server] # add server to list of readable sockets. 
    clients = {} 
    while True: 
     # check for a connection to the server or data ready from clients. 
     # readers will be empty on timeout. 
     readers,_,_ = select.select(to_read,[],[],0.5) 
     for reader in readers: 
      if reader is server: 
       client,address = reader.accept() 
       print('connected',address) 
       clients[client] = address # store address of client in dict 
       to_read.append(client) # add client to list of readable sockets 
      else: 
       # Simplified, really need a message protocol here. 
       # For example, could receive a partial UTF-8 encoded sequence. 
       data = reader.recv(1024) 
       if not data: # No data indicates disconnect 
        print('disconnected',clients[reader]) 
        to_read.remove(reader) # remove from monitoring 
        del clients[reader] # remove from dict as well 
       else: 
        print(clients[reader],data.decode()) 
     print('.',flush=True,end='') 

一个简单的客户端，假设您的IP地址为1.2.3.4。

import socket 
s = socket.socket() 
s.connect(('1.2.3.4',5000)) 
s.sendall('hello'.encode()) 
s.close()