django-rest-framework，在列表响应中添加“ includes”（带有分页）

Question

With an API I am currently working on in django-rest-framework, I am attempting to implement something similar to a feature in the json-api standard. Given a book model:

class Book(models.Model):
    title = models.CharField(max_length=255)
    author = models.ForeignKey(Author, on_delete=models.CASCADE)
    publisher = models.ForeignKey(Publisher, on_delete=models.CASCADE)

I want to include a parameter in the url, include , which lets the user define if they want to include author and publisher models in the response. The additional gotcha, is I am using limit/offset pagination. Thus, the following url:

https://my-api-domain/api/books?limit=5&offset=0&include=authors

should return something that looks like:

{
  "count": 152,
  "next": "https://my-api-domain/api/books/limit=5&offset=5&include=authors"
  "previous": null,
  "results": [
    {"id": 1, "title": "Book 1", "author": 1, "publisher": 18},
    {"id": 2, "title": "Book 2", "author": 2, "publisher": 26},
    ...
  ],
  "include": {
    "authors": [
      {"id": 1, "first_name": "Author", "last_name": "One"},
      {"id": 2, "first_name": "Author", "last_name": "Two"},
      ... for all author ids in paged `results` field above
    ]
  }
}

So far, my view looks like:

class BookViewSet(viewsets.ModelViewSet):
    queryset = Book.objects.all()
    serializer_class = BookSerializer
    permission_classes = (IsAuthenticated,)
    pagination_class = LimitOffsetPagination
    filter_class = BookFilterSet
    filter_backends = [DjangoFilterBackend]

    def list(self, request, *args, **kwargs):
        # Grab include from url parameters
        include = request.query_params.get('include', None)
        # Apply incoming filters to books
        queryset = self.filter_queryset(self.get_queryset())
        # Apply pagination to queryset
        page = self.paginate_queryset(queryset)

        # Assemble include data if necessary
        if include is not None:
            include_data = {}
            includes = include.split(',')
            response_data = serializer.data
            response_data['includes'] = {}
            for entity in includes:
                if entity == 'authors':
                    authors = Author.objects.distinct().filter(book__in=page)
                    authors_serializer = AuthorSerializer(authors, many=True)
                    include_data['authors'] = authors_serializer.data
                elif entity == 'publishers':
                    publishers = Publisher.objects.distinct().filter(book__in=page)
                    publishers_serializer = PublisherSerializer(publishers, many=True)
                    include_data['publishers'] = publishers_serializer.data

        serializer = self.get_serializer(page, many=True)

        # PROBLEM: How can I inject include_data into my response below???
        return self.get_paginated_response(serializer.data)

So I am able to take the incoming request, get the filtered and paged query, and pull the proper author and publisher serialized data. However, I am not sure, with the pagination response, how to inject this data (see the last two lines of the above code).

Any thoughts on how this can be accomplished? Is doing this in the view even the right spot? Or do I somehow need to be grabbing everything in my serializer? And if I do that, is there any way to get the include array as a sibling to the results array in my response (rather than include being embedded in results )?

Also, I realize that there is a django-rest-framwork-jsonapi package, however it also transforms my data in such a way that would require me doing drastic changes to my client code, which I am trying to avoid. Thus the 'light' version I am proposing here.

Answer 1

add

class CustomPagination(pagination.PageNumberPagination):
    def get_paginated_response(self, data, include_data):
        return Response({
            'links': {
                'next': self.get_next_link(),
                'previous': self.get_previous_link()
            },
            'count': self.page.paginator.count,
            'results': data,
            'include': include_data
        })

and configure its use

REST_FRAMEWORK = {
    'DEFAULT_PAGINATION_CLASS': 'my_project.apps.core.pagination.CustomPagination',
    'PAGE_SIZE': 100
}

then in your list method do

return self.get_paginated_response(serializer.data, include_data)