Feature/cursor-paginator

[janrito]

Hi

I have implemented a version of CursonPaginator based on ideas from both:
https://github.com/kitware-resonant/django-ninja-cursor-pagination/tree/master/ninja_cursor_pagination
and https://github.com/encode/django-rest-framework/blob/2465f9b4876ce16f2d22aa8d9f3cd20abde1b7c8/rest_framework/pagination.py#L583

This is an attempt for a minimal implementation that serves my needs, happy to hear any feedback.

It defines a custom paginator which can be added to any call:

from ninja.pagination import paginate, CursorPagination

@api.get('/events', response=List[EventSchema])
@paginate(CursorPagination)
def list_events(request):
    return Event.objects.all()

It defaults to using -created as the positioning attribute and allows for additional ordering attributes. These, along a page_size and max_page_size can be customised per view:

@api.get("/events")
@paginate(CursorPagination, ordering=("start_date", "end_date"), page_size=20, max_page_size=100)
def list_events(request):
    return Event.objects.all()

Where start_date is the positioning attribute

[vitalik]

Hi @janrito

I think thi default is not practicaly - not many will have 'created' - maybe default should be '-pk' ?

PAGINATION_DEFAULT_ORDERING: tuple[str, ...] = Field(
        ("-created",), alias="NINJA_PAGINATION_DEFAULT_ORDERING"
    )

[janrito]

Hi @janrito

I think thi default is not practicaly - not many will have 'created' - maybe default should be '-pk' ?

PAGINATION_DEFAULT_ORDERING: tuple[str, ...] = Field(
        ("-created",), alias="NINJA_PAGINATION_DEFAULT_ORDERING"
    )

Makes sense, have updated here: 1bddcaa

[danlamanna]

FWIW - this is related to #836 (FYI @zachmullen).