Re: ConnectionError handling problem

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Date	Sun, 20 Sep 2015 23:25:58 +1000
Subject	Re: ConnectionError handling problem
From	Chris Angelico <rosuav@gmail.com>
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On Sun, Sep 20, 2015 at 10:45 PM, Jon Ribbens
<jon+usenet@unequivocal.co.uk> wrote:
> On 2015-09-19, Mark Lawrence <breamoreboy@yahoo.co.uk> wrote:
>> On 19/09/2015 07:13, shiva upreti wrote:
>>>              try:
>>>                      r=requests.post(url, data=query_args)
>>>              except:
>>>                      print "Connection error"
>>
>> Never use a bare except in Python, always handle the bare minimum number
>> of exceptions that you need to, in this case your ConnectionError.
>
> While I entirely agree with the principle of being specific in what
> exceptions you are catching (with the absolute maximum being
> 'Exception'), it is often not obvious which ones you need to specify.
> The code above probably actually needs to catch EnvironmentError if
> it is intended to intercept all network problems.

General principle: If you don't know what you should be catching,
_catch nothing_. Anything that happens will get printed to the
console. Then when you find that something's getting thrown, you check
out what its name is, and maybe what its superclasses are (in case
there's a broader one worth catching), and only THEN do you stick in a
try/except.

ChrisA

Thread

ConnectionError handling problem shiva upreti <katewinslet626@gmail.com> - 2015-09-18 23:13 -0700
  Re: ConnectionError handling problem Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-19 17:18 +0100
    Re: ConnectionError handling problem Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-09-20 12:45 +0000
      Re: ConnectionError handling problem Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-20 14:13 +0100
        Re: ConnectionError handling problem Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-09-20 13:28 +0000
      Re: ConnectionError handling problem Chris Angelico <rosuav@gmail.com> - 2015-09-20 23:25 +1000
        Re: ConnectionError handling problem Jon Ribbens <jon+usenet@unequivocal.co.uk> - 2015-09-20 13:33 +0000
  Re: ConnectionError handling problem Laura Creighton <lac@openend.se> - 2015-09-20 16:40 +0200
    Re: ConnectionError handling problem shiva upreti <katewinslet626@gmail.com> - 2015-09-23 19:49 -0700
      Re: ConnectionError handling problem Laura Creighton <lac@openend.se> - 2015-09-24 12:38 +0200
        Re: ConnectionError handling problem shiva upreti <katewinslet626@gmail.com> - 2015-09-24 20:52 -0700
        Re: ConnectionError handling problem shiva upreti <katewinslet626@gmail.com> - 2015-09-24 22:41 -0700
        Re: ConnectionError handling problem shiva upreti <katewinslet626@gmail.com> - 2015-09-24 22:42 -0700

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