Using infinite scroll with Django Rest Framework?

Question

I am creating a REST API using Django Rest Framework. The API will serve large amount of data and I want to use infinite scrolling on the page. I would like to use Angular for the frontend. I am not sure how to serve the data such that not all data has to be sent once but only when the user scrolls down.

I am using serializer class -

class CompanySerializer(serializers.ModelSerializer):
    class Meta:
        model = Company
        fields = ('company_name', 'location', 'founded_year')

I am not sure about how to implement this. Should i use Django Endless Pagination or could it be done by using the pagination provided by django-rest-framework. I am also not sure about how the frontend of this would work. Web development newbie here, please help.

Answer 1

Create a ListAPIView subclass

from rest_framework import pagination, generics

class CompanyPagination(pagination.PageNumberPagination):
    page_size = 20  # the no. of company objects you want to send in one go

# Assume url for this view is /api/v1/companies/
class CompanyListView(generics.ListAPIView):
    queryset = Company.objects.all()
    serializer_class = CompanySerializer
    pagination_class = CompanyPagination

Once this is done, you can get first 20 by calling the http://your_domain.com/api/v1/companies/?page=1, ?page=2 will give 21st company to 40th company and so on. (Not specifying ?page= is like doing ?page=1)

On your AngularJS side, you will maintain some variable which will hold which page number to fetch next. Now you can bind your API request to either click event on some Load More type of button, or may be you can detect whether user has scrolled to the bottom, and then do the API request and fetch next set of Company objects.

Note:

It is not compulsory to use PageNumberPagination, you can even use LimitOffsetPagination or CursorPagination to achieve your objective. Read more about various pagination styles here

Answer 2

You should give CursorPagination a try. I don't know exactly whether it's infinite or not but it's definitively for huge sets.