Django Rest Framework: DRYer pagination for custom actions

user_5013234 0
Viewed 1933

Suppose I need to set up several GET endpoints that look like this objects/past, objects/future. Example:

@action(detail=False, methods=["GET"], name="Past Objects")
def past(self, request, *args, **kwargs):
    startdate = datetime.datetime.now()
    some_user = UserProfile.objects.get(user__username="someuser")

    queryset = self.queryset.filter(
        other__attribute__profile=some_user,
        creation_date__lte=startdate
        ).order_by("-creation_date")

    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)

The above works just fine. But is there anyway to avoid the page = ... -> serializer= ... part?

I have specified this in my ModelViewSet:

pagination_class = CustomObjectPagination

But it seems the pagination is only auto-applied to default methods like get_queryset and not custom actions. Do I have to write this boilerplate every time I specify a custom action like past?

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)

Edit: Should have made it clearer that I'm asking specifically whether there's a built-in way to do the above.

django-rest-framework django
2 Answers

I don't think we have any built-in to apply pagination on actions. But, we can have a simple decorator to do this. Make sure that your action returns a list or QuerySet when using this decorator.

from functools import wraps
from django.db.models import QuerySet

def paginate(func):

    @wraps(func)
    def inner(self, *args, **kwargs):
        queryset = func(self, *args, **kwargs)
        assert isinstance(queryset, (list, QuerySet)), "apply_pagination expects a List or a QuerySet"

        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)
    return inner

@paginate
@action(detail=False, methods=["GET"], name="Past Objects")
def past(self, request, *args, **kwargs):
    startdate = datetime.datetime.now()
    some_user = UserProfile.objects.get(user__username="someuser")

    queryset = self.queryset.filter(
        other__attribute__profile=some_user,
        creation_date__lte=startdate
        ).order_by("-creation_date")

    return queryset
user_99178710

I wrote a simple function for that:

def response_with_paginator(viewset, queryset):
    page = viewset.paginate_queryset(queryset)
    if page is not None:
        serializer = viewset.get_serializer(page, many=True)
        return viewset.get_paginated_response(serializer.data)

    return Response(viewset.get_serializer(queryset, many=True).data)

Usage is like:

@action(...)
def comments(self, ...):
    queryset = Comment.objects.filter(...)
    return response_with_paginator(self, queryset)
user_72858630
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