The Queryset Attribute Of Django Rest Api Generic Views
I am trying to understand the django rest framework generic API views, the documentation tells me that while overriding methods of the generic views, I shouldn't be accessing the q
Solution 1:
To further expand, the source code will tell you the truth.
assert self.queryset isnotNone, (
"'%s' should either include a `queryset` attribute, ""or override the `get_queryset()` method."
% self.__class__.__name__
)
queryset = self.queryset
ifisinstance(queryset, QuerySet):
# Ensure queryset is re-evaluated on each request.
queryset = queryset.all()
return queryset
- First it checks queryset is defined
- Second it checks if the queryset specified is an instance of Django's Queryset class
- Third it re-evaluates (makes a database query) the queryset and sets the results
- Fourth it returns the results
The warning about using self.queryset directly is that results are cached when evaluated so further references to this value will not be up to date as opposed of using self.get_queryset().
Solution 2:
for simple views, the queryset
attribute would quickly get your started. But in real life, normally, we have permissions on models, for example, the default queryset
for a user would be filtered queryset based on request.user. The get_queryset
method would become
defget_queryset(self):
return self.model.objects.filter(user=self.request.user)
the above get_queryset
method is just an example present real-life API design.
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