Python:如何区分套接字错误和超时？

Question

我有以下代码:

try:
    while 1:
        s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
        s.settimeout(5);
        s.connect((HOST,PORT))
        print("before send")
        #time.sleep(10);
        #s.sendall('GET / HTTP/1.1\r\nConnection: Keep-Alive\r\nHost: www.google.lt\r\n\r\n')
        data=s.recv(52)
        print("after send");
        s.close()
        if string.find(data,"HTTP/1.1 200 OK") == -1:
            print("Lost Connection")
        print(data)
        time.sleep(2)
except KeyboardInterrupt:
    print("CTRL C occured")
except socket.error:
    print("socket error occured: ")
except socket.timeout:
    print("timeout error")

我已经注释了sendall函数来测试recv如何产生超时异常。但问题是我得到 socket.error 异常。如果我将最后一行代码更改为:

except socket.timeout:
    print("timeout error")
except socket.error:
     print("socket error occured: ")

然后我得到 socket.timeout 异常。那么真正产生了什么异常呢？

Answer 1

socket.timeout 是 socket.error 的子类。真的是 socket.timeout。当您首先捕捉到 socket.error 时，您会捕捉到更一般的情况。

>>> issubclass(socket.timeout, socket.error)
True

这段代码是正确的:

except socket.timeout:
 print("timeout error")
except socket.error:
 print("socket error occured: ")

try catch 特定的socket.timeout，然后是其他socket.error。