如何从socket.timeout异常处理程序中捕获KeyboardInterrupt？

Question

我正在尝试开发一个简单的套接字服务器，该服务器具有非阻塞的接受（使用settimeout），但是我希望能够使用Ctrl-C（KeyboardInterrupt）停止它。

我的代码如下：

import socket

host = '127.0.0.1'
port = 5000

s = socket.socket()
s.settimeout(1)
s.bind((host, port))
s.listen(1)
print('Server started')
while True:
    try:
        conn, addr = s.accept()
    except socket.timeout:
        pass
    except Exception as exc:
        print(str(exc))
        print('Server closing')
        s.close()
        break
    except KeyboardInterrupt:
        print('Server closing')
        s.close()
        break
    else:
        print('Connection from', addr)

但是因为它发生在套接字超时异常处理程序中，所以 KeyboardInterrupt 永远不会被捕捉到。按下 Ctrl-C 后会得到以下输出：

c:\Users\JMatos\MEOCloud\Python>python file_server.py
Server started
Traceback (most recent call last):
  File "file_server.py", line 40, in <module>
    conn, addr = s.accept()
  File "C:\Python35-32\lib\socket.py", line 195, in accept
    fd, addr = self._accept()
socket.timeout: timed out

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "file_server.py", line 40, in <module>
    conn, addr = s.accept()
KeyboardInterrupt

有没有办法在socket.timeout异常处理程序中捕捉KeyboardInterrupt异常？

我的环境为Windows 7P+SP1 x64，Python 3.5.2 32b。

提前致谢， JM

- jmatos

Answer 1

问题不在于套接字超时，而在于您期望抛出异常的位置。请将代码更改为以下内容：

try:
    while True:
        try:
            conn, addr = s.accept()
        except socket.timeout:
             pass
        except Exception as exc:
             print(str(exc))
             print('Server closing')
             s.close()
             break
    else:
        print('Connection from', addr)
except KeyboardInterrupt:
    print('Server closing')
    s.close()

- Labrys Knossos

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谢谢，解决了。 - jmatos