Pagination with Django Ninja

views.py

'''
Credit to https://github.com/vitalik/django-ninja/issues/104#issuecomment-805939752 🔥

python '3.11.6'
django '4.2.7'
ninja '1.0.1'
pydantic '2.5.2'
'''

from ninja import Router
from typing import Optional
from datetime import datetime
from django.core.paginator import Page, Paginator

def replace_query_param(url, key, val):
    from urllib import parse
    from django.utils.encoding import force_str

    (scheme, netloc, path, query, fragment) = parse.urlsplit(force_str(url))
    query_dict = parse.parse_qs(query, keep_blank_values=True)
    query_dict[force_str(key)] = [force_str(val)]
    query = parse.urlencode(sorted(query_dict.items()), doseq=True)
    return parse.urlunsplit((scheme, netloc, path, query, fragment))


def get_next_page_url(request, page: Page) -> Optional[str]:
    if not page.has_next():
        return None
    return replace_query_param(request.build_absolute_uri(), "page", page.number + 1)


def get_previous_page_url(request, page: Page) -> Optional[str]:
    if not page.has_previous():
        return None
    return replace_query_param(request.build_absolute_uri(), "page", page.number - 1)
  

router = Router()
@router.get(
    "/users",
    response=ListStdResponse[Union[UserSchema, None]],
)
def list_users(request, page: int = 1, limit: int = 5):
    users = model.User.objects.all()
    paginator_page = Paginator(users, per_page=limit).get_page(page)

    users = [user for user in paginator_page.object_list]
    next_page = get_next_page_url(request, paginator_page).__str__()
    previous_page = get_previous_page_url(request, paginator_page).__str__()

    return {
        "data": users,
        "count": paginator_page.paginator.count,
        "next": next_page,
        "previous": previous_page,
    }