Ah, looks better.
But, 2 questions:
1. I should also catch ConnectionResetError I am guessing.
2. How do I handle all other exceptions, just say Exception: and handle them? I
want to silently ignore them.
Thanks...
On Tuesday, April 9, 2013 2:41:51 PM UTC+3, cab...@gmail.com wrote:
> Hi,
>
>
>
> I have been using Java/Perl professionally for many years and have been
> trying to learn python3 recently. As my first program, I tried writing a
> class for a small project, and I am having really hard time understanding
> exception handling in urllib and in python in general...
>
> Basically, what I want to do is very simple, try to fetch something
> "tryurllib.request.urlopen(request)", and:
>
> - If request times out or connection is reset, re-try n times
>
> - If it fails, return an error
>
> - If it works return the content.
>
>
>
> But, this simple requirement became a nightmare for me. I am really confused
> about how I should be checking this because:
>
> - When connection times out, I sometimes get URLException with "reason"
> field set to socket.timeout, and checking (isinstance(exception.reason,
> socket.timeout)) works fine
>
> - But sometimes I get socket.timeout exception directly, and it has no
> "reason" field, so above statement fails, since there is no reason field
> there.
>
> - Connection reset is a totally different exception
>
> - Not to mention, some exceptions have msg / reason / errno fields but some
> don't, so there is no way of knowing exception details unless you check them
> one by one. The only common thing I could was to find call __str__()?
>
> - Since, there are too many possible exceptions, you need to catch
> BaseException (I received URLError, socket.timeout, ConnectionRefusedError,
> ConnectionResetError, BadStatusLine, and none share a common parent). And,
> catching the top level exception is not a good thing.
>
>
>
> So, I ended up writing the following, but from everything I know, this looks
> really ugly and wrong???
>
>
>
> try:
>
> response = urllib.request.urlopen(request)
>
> content = response.read()
>
> except BaseException as ue:
>
> if (isinstance(ue, socket.timeout) or (hasattr(ue, "reason") and
> isinstance(ue.reason, socket.timeout)) or isinstance(ue,
> ConnectionResetError)):
>
> print("REQUEST TIMED OUT")
>
>
>
> or, something like:
>
>
>
> except:
>
> (a1,a2,a3) = sys.exc_info()
>
> errorString = a2.__str__()
>
> if ((errorString.find("Connection reset by peer") >= 0) or
> (errorString.find("error timed out") >= 0)):
>
>
>
> Am I missing something here? I mean, is this really how I should be doing it?
>
>
>
> Thanks.
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