Pagination

Django Ninja comes with a pagination support. This allows you to split large result sets into individual pages.

To apply pagination to a function - just apply paginate decorator:

from ninja.pagination import paginate

@api.get('/users', response=List[UserSchema])
@paginate
def list_users(request):
    return User.objects.all()

That's it!

Now you can query users with limit and offset GET parameters

/api/users?limit=10&offset=0

by default limit is set to 100 (you can change it in your settings.py using NINJA_PAGINATION_PER_PAGE)

Built in Pagination Classes

LimitOffsetPagination (default)

This is the default pagination class (You can change it in your settings.py using NINJA_PAGINATION_CLASS path to a class)

from ninja.pagination import paginate, LimitOffsetPagination

@api.get('/users', response=List[UserSchema])
@paginate(LimitOffsetPagination)
def list_users(request):
    return User.objects.all()

Example query:

/api/users?limit=10&offset=0

this class has two input parameters:

• limit - defines a number of queryset on the page (default = 100, change in NINJA_PAGINATION_PER_PAGE)
• offset - set's the page window offset (default: 0, indexing starts with 0)

PageNumberPagination

from ninja.pagination import paginate, PageNumberPagination

@api.get('/users', response=List[UserSchema])
@paginate(PageNumberPagination)
def list_users(request):
    return User.objects.all()

Example query:

/api/users?page=2

this class has one parameter page and outputs 100 queryset per page by default (can be changed with settings.py)

Page numbering start with 1

you can also set custom page_size value individually per view:

@api.get("/users")
@paginate(PageNumberPagination, page_size=50)
def list_users(...

Accessing paginator parameters in view function

If you need access to Input parameters used for pagination in your view function - use pass_parameter argument

In that case input data will be available in **kwargs:

@api.get("/someview")
@paginate(pass_parameter="pagination_info")
def someview(request, **kwargs):
    page = kwargs["pagination_info"].page
    return ...

Creating Custom Pagination Class

To create a custom pagination class you should subclass ninja.pagination.PaginationBase and override the Input and Output schema classes and paginate_queryset(self, queryset, request, **params) method:

• The Input schema is a Schema class that describes parameters that should be passed to your paginator (f.e. page-number or limit/offset values).
• The Output schema describes schema for page output (f.e. count/next-page/items/etc).
• The paginate_queryset method is passed the initial queryset and should return an iterable object that contains only the data in the requested page. This method accepts the following arguments:
  • queryset: a queryset (or iterable) returned by the api function
  • pagination - the paginator.Input parameters (parsed and validated)
  • **params: kwargs that will contain all the arguments that decorated function received

Example:

from ninja.pagination import paginate, PaginationBase
from ninja import Schema


class CustomPagination(PaginationBase):
    # only `skip` param, defaults to 5 per page
    class Input(Schema):
        skip: int


    class Output(Schema):
        items: List[Any] # `items` is a default attribute
        total: int
        per_page: int

    def paginate_queryset(self, queryset, pagination: Input, **params):
        skip = pagination.skip
        return {
            'items': queryset[skip : skip + 5],
            'total': queryset.count(),
            'per_page': 5,
        }


@api.get('/users', response=List[UserSchema])
@paginate(CustomPagination)
def list_users(request):
    return User.objects.all()

Tip: You can access request object from params:

def paginate_queryset(self, queryset, pagination: Input, **params):
    request = params["request"]

Output attribute

By defult page items are placed to 'items' attribute. To override this behaviour use items_attribute:

class CustomPagination(PaginationBase):
    ...
    class Output(Schema):
        results: List[Any]
        total: int
        per_page: int

    items_attribute: str = "results"

Apply pagination to multiple operations at once

There is often a case when you need to add pagination to all views that returns querysets or list

You can use a builtin router class (RouterPaginated) that automatically injects pagination to all operations that defined response=List[SomeSchema]:

from ninja.pagination import RouterPaginated

router = RouterPaginated()


@router.get("/items", response=List[MySchema])
def items(request):
    return MyModel.objects.all()

@router.get("/other-items", response=List[OtherSchema])
def ohter_items(request):
    return OtherModel.objects.all()

In this example both operations will have pagination enabled

to apply pagination to main api instance use default_router argument:

api = NinjaAPI(default_router=RouterPaginated())

@api.get(...