WorkHorseIndustries/drf-raw-pagination

Pagination for RawQuerySets

#drf-raw-pagination

Provides pagination for Django's RawQuerySet. The original intention was for this to be used with django-rest-framework.

There are three different components involved, the PaginatedRawQuerySet, the Paginator, and Pagination class.

##PaginatedRawQuerySet PaginatedRawQuery is a subclass of RawQuerySet, extending it with count, and page methods.

count will hit the Database the first time it's called, and return the total count of all records matching the query

    PaginatedRawQuery("SELECT * FROM foo_bar")

count() will execute

    SELECT COUNT(*) FROM (SELECT * FROM foo_bar) b;

and cache the result so future calls to count wont hit the database.

page takes two parameters limit and offset which are used by there respective SQL expressions to return a paged result set.

    PaginatedRawQuery("SELECT * FROM foo_bar")

page(2, 3) will execute

    SELECT * FROM foo_bar LIMIT 2 OFFSET 3

##Paginator RawPaginator and RawPage implements the Paginator and Page contracts specified by Django. They rely on the count and page being implemented by the underlying queryset.

##Pagination RawablePageNumberPaginator extends DRF's PageNumberPaginator, it checks whether the queryset is an instance of PaginatedRawQuerySet and if so, it uses the RawPaginator otherwise it uses the default DjangoPaginator.

##Example models.py

from djang.db import models
from .managers import FooManager

class Foo(models.Model):
    name = model.CharField(max_length=10)

    objects = FooManager()

manage.py

from django.db import models
from raw_pagination.db.models.query import PaginatedRawQuerySet

class FooManager(models.Manager):

    def paged_raw(self, raw_query, params=None, translations=None, using=None):
        if using is None
            using = self.db
        return PaginatedRawQuerySet(raw_query, model=self.model, params=params, 
                                    translations=translations, using=using)

serializers.py

from rest_framework import serializers
from .models import Foo

class FooSerializer(serializers.ModelSerializer):

    class Meta:
        model = Foo
        fields = ('name')

api.py

from rest_framework import generics
from rest_framework.mixins import ListModelMixin
from .serializers import FooSerializer
from .models import Foo
from raw_pagination.pagination import RawablePageNumberPagination


class FooView(ListModelMixin, generics.GenericView):
    serializer_class = FooSerializer
    pagination_class = RawablePageNumberPagination

    def get_queryset(self):
        Foo.objects.paged_raw("SELECT * FROM foo_foo")