source: pagination.py

# Pagination

> Django provides a few classes that help you manage paginated data – that is, data that’s split across several pages, with “Previous/Next” links.
>
> &mdash; [Django documentation][cite]

REST framework includes support for customizable pagination styles. This allows you to modify how large result sets are split into individual pages of data.

The pagination API can support either:

* Pagination links that are provided as part of the content of the response.
* Pagination links that are included in response headers, such as `Content-Range` or `Link`.

The built-in styles currently all use links included as part of the content of the response. This style is more accessible when using the browsable API.

Pagination is only performed automatically if you're using the generic views or viewsets. If you're using a regular `APIView`, you'll need to call into the pagination API yourself to ensure you return a paginated response. See the source code for the `mixins.ListMixin` and `generics.GenericAPIView` classes for an example.

## Setting the pagination style

The default pagination style may be set globally, using the `DEFAULT_PAGINATION_CLASS` settings key. For example, to use the built-in limit/offset pagination, you would do:

    REST_FRAMEWORK = {
        'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.LimitOffsetPagination'
    }

You can also set the pagination class on an individual view by using the `pagination_class` attribute. Typically you'll want to use the same pagination style throughout your API, although you might want to vary individual aspects of the pagination, such as default or maximum page size, on a per-view basis.

## Modifying the pagination style

If you want to modify particular aspects of the pagination style, you'll want to override one of the pagination classes, and set the attributes that you want to change.

    class LargeResultsSetPagination(PageNumberPagination):
        paginate_by = 1000
        paginate_by_param = 'page_size'
        max_paginate_by = 10000

    class StandardResultsSetPagination(PageNumberPagination):
        paginate_by = 100
        paginate_by_param = 'page_size'
        max_paginate_by = 1000

You can then apply your new style to a view using the `.pagination_class` attribute:

    class BillingRecordsView(generics.ListAPIView):
        queryset = Billing.objects.all()
        serializer = BillingRecordsSerializer
        pagination_class = LargeResultsSetPagination

Or apply the style globally, using the `DEFAULT_PAGINATION_CLASS` settings key. For example:

    REST_FRAMEWORK = {
        'DEFAULT_PAGINATION_CLASS': 'apps.core.pagination.StandardResultsSetPagination'
    }

# API Reference

## PageNumberPagination

## LimitOffsetPagination

---

# Custom pagination styles

To create a custom pagination serializer class you should subclass `pagination.BasePagination` and override the `paginate_queryset(self, queryset, request, view=None)` and `get_paginated_response(self, data)` methods:

* The `paginate_queryset` method is passed the initial queryset and should return an iterable object that contains only the data in the requested page.
* The `get_paginated_response` method is passed the serialized page data and should return a `Response` instance.

Note that the `paginate_queryset` method may set state on the pagination instance, that may later be used by the `get_paginated_response` method.

## Example

Let's modify the built-in `PageNumberPagination` style, so that instead of include the pagination links in the body of the response, we'll instead include a `Link` header, in a [similar style to the GitHub API][github-link-pagination].

    class LinkHeaderPagination(pagination.PageNumberPagination):
        def get_paginated_response(self, data):
            next_url = self.get_next_link()
            previous_url = self.get_previous_link()

            if next_url is not None and previous_url is not None:
                link = '<{next_url}; rel="next">, <{previous_url}; rel="prev">'
            elif next_url is not None:
                link = '<{next_url}; rel="next">'
            elif previous_url is not None:
                link = '<{previous_url}; rel="prev">'
            else:
                link = ''

            link = link.format(next_url=next_url, previous_url=previous_url)
            headers = {'Link': link} if link else {}

            return Response(data, headers=headers)

## Using your custom pagination class

To have your custom pagination class be used by default, use the `DEFAULT_PAGINATION_CLASS` setting:

    REST_FRAMEWORK = {
        'DEFAULT_PAGINATION_CLASS': 'my_project.apps.core.pagination.LinkHeaderPagination',
        'PAGINATE_BY': 10
    }

API responses for list endpoints will now include a `Link` header, instead of including the pagination links as part of the body of the response, for example:

---

![Link Header][link-header]

*A custom pagination style, using the 'Link' header'*

---

# Third party packages

The following third party packages are also available.

## DRF-extensions

The [`DRF-extensions` package][drf-extensions] includes a [`PaginateByMaxMixin` mixin class][paginate-by-max-mixin] that allows your API clients to specify `?page_size=max` to obtain the maximum allowed page size.

[cite]: https://docs.djangoproject.com/en/dev/topics/pagination/
[github-link-pagination]: https://developer.github.com/guides/traversing-with-pagination/
[link-header]: ../img/link-header-pagination.png
[drf-extensions]: http://chibisov.github.io/drf-extensions/docs/
[paginate-by-max-mixin]: http://chibisov.github.io/drf-extensions/docs/#paginatebymaxmixin
