Speno's Pythonic Avocado 12.10.2004

Sorry, I timed out there...

Sometimes you don't have time to wait forever...

class TimeoutFunctionException(Exception):
    """Exception to raise on a timeout"""
    pass

class TimeoutFunction:
    def __init__(self, function, timeout):
        self.timeout = timeout
        self.function = function

    def handle_timeout(self, signum, frame):
        raise TimeoutFunctionException()

    def __call__(self, *args):
        old = signal.signal(signal.SIGALRM, self.handle_timeout)                
        signal.alarm(self.timeout)                                              
        try:                                                                    
            result = self.function(*args)                                       
        finally:                                                                
            signal.signal(signal.SIGALRM, old)                                  
        signal.alarm(0)                                                         
        return result 

if __name__ == '__main__':
    import sys
    stdin_read = TimeoutFunction(sys.stdin.readline, 1)
    try:
        line = stdin_read()
    except TimeoutFunctionException:
        print 'Too slow!'
    else:
        print 'You made it!'

Thanks to mjd for the original idea implemented in $@%.

I searched the Python Cookbook before writing this code and found nothing. The day after I wrote this TimeoutFunction class, I saw this python cookbook recipe on Daily Python -URL. D'oh!