urlopen, six, and py2

Path	csiph.com!aioe.org!.POSTED!not-for-mail
From	Fabien <fabien.maussion@gmail.com>
Newsgroups	comp.lang.python
Subject	urlopen, six, and py2
Date	Wed, 2 Mar 2016 15:05:46 +0100
Organization	Aioe.org NNTP Server
Lines	40
Message-ID	<nb6rvp$cub$1@gioia.aioe.org> (permalink)
NNTP-Posting-Host	+L+NlaBbFxmjN1Tx9NZnQA.user.gioia.aioe.org
Mime-Version	1.0
Content-Type	text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding	7bit
X-Complaints-To	abuse@aioe.org
User-Agent	Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1
X-Notice	Filtered by postfilter v. 0.8.2
X-Mozilla-News-Host	news://news.aioe.org:119
Xref	csiph.com comp.lang.python:103869

Show key headers only | View raw

Hi,

it seems that urlopen had no context manager for versions < 3. The 
following code therefore will crash on py2 but not on py3.

from six.moves.urllib.request import urlopen
with urlopen('http://www.google.com') as resp:
     _ = resp.read()

Error:
AttributeError: addinfourl instance has no attribute '__exit__'

I actually wonder if this is not something that the six library should 
take care of upstream, but in the meantime I could simply do what is 
suggested on this stackoverflow post:

http://stackoverflow.com/questions/30627937/tracebaclk-attributeerroraddinfourl-instance-has-no-attribute-exit

My question is: why does the python3 version need a "with" block while 
the python2 version doesn't? Can I skip the "with" entirely, or should I 
rather do the following:

from six.moves.urllib.request import urlopen

try:
     with urlopen('http://www.google.com') as resp:
         _ = resp.read()
except AttributeError:
     # python 2
     resp = urlopen('http://www.google.com')
     _ = resp.read()

(which is quite ugly).

Thanks!

Fabien

Back to comp.lang.python | Previous | Next — Next in thread | Find similar | Unroll thread

Thread

urlopen, six, and py2 Fabien <fabien.maussion@gmail.com> - 2016-03-02 15:05 +0100
  Re: urlopen, six, and py2 Matt Wheeler <m@funkyhat.org> - 2016-03-02 14:35 +0000
    Re: urlopen, six, and py2 Fabien <fabien.maussion@gmail.com> - 2016-03-02 16:36 +0100
      Re: urlopen, six, and py2 Chris Angelico <rosuav@gmail.com> - 2016-03-03 03:17 +1100
  Re: urlopen, six, and py2 Chris Angelico <rosuav@gmail.com> - 2016-03-03 01:53 +1100

csiph-web