On Sat, 04 Mar 2006 00:10:17 +0100, Rene Pijlman wrote:
> I've writen an application that uses urllib2, urlparse, robotparser and
> some other modules in the battery pack. One day my app failed with an
> urllib2.HTTPError. So I catch that. But then I get a urllib2.URLError, so
> I catch that too. The next day, it encounters a urllib2.HTTPError, then a
> IOError, a socket.timeout, httplib.InvalidURL,...
>
> How do you program robustly with these modules throwing all those
> different (and sometimes undocumented) exceptions at you?
How robust do you want to be? Do you want to take a leaf out of Firefox
and Windows XP by generating an error report and transmitting it back to
the program maintainer?
> A catchall seems like a bad idea, since it also catches AttributeErrors
> and other bugs in the program.
ExpectedErrors = (URLError, IOError)
ErrorsThatCantHappen = (LookupError, ArithmeticError, AssertionError)
try:
process_things()
except ExpectedErrors:
recover_from_error_gracefully()
except ErrorsThatCantHappen:
print "Congratulations! You have found a program bug!"
print "For a $327.68 reward, please send the following " \
"traceback to Professor Donald Knuth."
raise
except:
print "An unexpected error occurred."
print "This probably means the Internet is broken."
print "If the bug still occurs after fixing the Internet, " \
"it may be a program bug."
log_error()
sys.exit()
--
Steven.
--
http://mail.python.org/mailman/listinfo/python-list
