25 lines
796 B
Python
25 lines
796 B
Python
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from django.core.exceptions import ObjectDoesNotExist
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from django.http import Http404
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class ForId(object):
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''' Mixin class that gives you new classmethods: for_id for_id_or_404.
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These let you retrieve an instance of the class by specifying the model ID.
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Your subclass must define __MODEL__ as a class attribute. This will be the
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model class that we wrap. There must also be a constructor that takes a
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single argument: the instance of the model that we are controlling. '''
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@classmethod
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def for_id(cls, id_):
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id_ = int(id_)
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obj = cls.__MODEL__.objects.get(pk=id_)
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return cls(obj)
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@classmethod
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def for_id_or_404(cls, id_):
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try:
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return cls.for_id(id_)
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except ObjectDoesNotExist:
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return Http404
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