Django Rest Framework : Pagination with annotated Queryset - django

Question

I am currently doing a project which requires pagination. A list of Images is provided to the user and whether they were Favorited or not by user.
Favorited Images are kept in a separate table.
In order to provide a list of images and ones that were Favorited by the user an annotate.
def _get_queryset(self, request):
user_favorited = DjImagingImagefavorites.objects.filter(ifv_img_recordid__exact=OuterRef('pk'), ifv_user_id__exact=request.user.profile)
queryset = DjImagingImage.objects.all().annotate(favorited=Exists(user_favorited))
return queryset
Then in the list function
def list(self, request):
images = self._get_queryset(request)
page = self.paginate_queryset(images) #Breaks here
The Query then throws an error.
]Cannot use an aggregate or a subquery in an expression used for the group by list of a GROUP BY clause.
Due to an oddities of how the paginate function performs the count and constructs an illegal sql statement.
Question is - Is their a better way about going to do this or should this work perfectly as I thought it should have?

Answer 1

A solution that I found works is coded below
def list(self, request):
images = self._get_queryset(request)
#page = self.paginate_queryset(images)
return self.paginate(images)
I create a wrapper called paginate
def paginate(self, queryset):
"""Calculate paginated QuerySet and wrap in a Response.
Args:
queryset - the queryset to be paginated
"""
page = self.paginate_queryset(queryset)
if page is not None:
serializer = self.get_serializer(page, many=True)
return self.get_paginated_response(serializer.data)
serializer = self.get_serializer(queryset, many=True)
return Response(serializer.data)
For those who are wondering the queryset I am constructing
def get_queryset(self):
"""Return the modified/prepared master QuerySet.
Returns:
QuerySet<DjImagingImage>: The modified master QuerySet
"""
return DjImagingImage.objects.annotate(
mine=FilteredRelation('djimaginguserspecifics',condition=Q(djimaginguserspecifics__usp_emp_employeeid=self.request.user.profile)),
usp_favorite=F('mine__usp_favorite'),
usp_inhistory=F('mine__usp_inhistory'),
usp_emp_employeeid=F('mine__usp_emp_employeeid'),
usp_lastviewed=F('mine__usp_lastviewed'),
comment_count=Count('djimagingimagecomment'))