Getting NameError for an exception handling

Question

I wanted to list an object(club) detail on a page by extracting its id from url and giving it to django models api. It is working when that id exist in the database. But when I try giving id in url which does not exist then the model api gives this error:

club = Club.objects.get(id=8) Traceback (most recent call last): File "", line 1, in File "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py", line 131, in get return self.get_query_set().get(*args, **kwargs) File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py", line 366, in get % self.model._meta.object_name) DoesNotExist: Club matching query does not exist.

So I added an exception handler for this error in my view. Here is the code:

def club_detail(request, offset):
    try:
        club_id = int(offset)
        club = Club.objects.get(id=club_id)
    except (ValueError, DoesNotExist):
        raise HTTP404()
    return render_to_response('home/club_detail.html', {'club': club }, context_instance = RequestContext(request))

But it is not catching DoesNotExist error and instead giving a NameError in browser:

NameError at /club/8/
  global name 'DoesNotExist' is not defined
  Request Method:   GET
  Request URL:  http://127.0.0.1:8000/club/8/
  Django Version:   1.4.1
  Exception Type:   NameError
  Exception Value:  
  global name 'DoesNotExist' is not defined

How can I make it working? Thanks in advance

David Robinson · Accepted Answer · 2016-07-28 20:30:30Z

8

DoesNotExist is implemented as an attribute of the model itself. Change your line to:

    except (ValueError, Club.DoesNotExist):

Alternatively, since all DoesNotExist errors inherit the ObjectDoesNotExist class, you can do:

from django.core.exceptions import ObjectDoesNotExist

...

    except (ValueError, ObjectDoesNotExist):

as described here.

edited Jul 28, 2016 at 20:30

answered Sep 8, 2012 at 3:42

David Robinson

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Comments

DimmuR · Accepted Answer · 2012-09-10 10:11:49Z

1

You cannot use DoesNotExist directly - it shoul'd be Club.DoesNotExist so your code would look like:

def club_detail(request, offset):
    try:
        club_id = int(offset)
        club = Club.objects.get(id=club_id)
    except (ValueError, Club.DoesNotExist):
        raise HTTP404()
    return render_to_response('home/club_detail.html', {'club': club }, context_instance = RequestContext(request))

answered Sep 10, 2012 at 10:11

DimmuR

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Comments

nneonneo · Accepted Answer · 2012-09-08 02:37:53Z

0

You need to import DoesNotExist:

from django.core.exceptions import DoesNotExist

answered Sep 8, 2012 at 2:37

nneonneo

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2 Comments

karambir Over a year ago

I tried this but it is giving ImportError. And I also opened exceptions.py file, but there is no DoesNotExist class. (I'm running django 1.4)

Sheena Over a year ago

cannot import name DoesNotExist

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