DRF how to return list filtered by lookup w/ custom router and modelviewset - django-rest-framework

Question

I tried to search for answers as much as I can but I still don't know how to achieve my goal here.
My goal:
I need two api endpoints, one returns a list filtered by a lookup fields, and another returns an obj filtered by another field, both using GET method. For example:
<ip>/api/books/bycategory/{category_lookup}/ This endpoint will return a list of books filtered by a category
<ip>/api/books/byid/{id_lookup}/ This returns one book matches the specified id (not pk)
Since there's no built-in router that suits my needs here because the built-in ones don't provide url pattern with lookup that returns a list, so I figured I need to have a custom router of my own, so here's what I have:
class CustomRouter(routers.SimpleRouter):
routes = [
routers.DynamicRoute(
url=r'^{prefix}/{url_path}/{lookup}{trailing_slash}$',
name='{basename}-{url_name}',
detail=True,
initkwargs={}
)
]
router = CustomRouter()
router.register('books', BookViewSet)
and my serializer:
class BookSerializer(serializers.ModelSerializer):
class Meta:
model = BookKeeper
fields = '__all__'
Right until here I think I'm on the right track, but when it comes to the view, thats where i can't quite figure out. Right now I only have this incomplete viewset:
class BookViewSet(viewsets.ReadOnlyModelViewSet):
queryset = BookKeeper.objects.all()
serializer_class = BookSerializer
#action(detail=True)
def bycategory(self, request):
lookup_field = 'category'
#action(detail=True)
def byid(self, request):
lookup_field = 'id'
My first question here is I "think" {url_path} in the router url matches the method name with #action specified in the viewset somehow and that how they are connected, am I correct?
Second question is how do I use {lookup} value in the view?
Third, what's the lookup_field for if I'm to use like:
def bycategory(self, request):
return Response(BookKeeper.objects.filter(category=<lookup_value>))
Lastly what should my viewset be like anyway?
Any input will be appreciated.

Answer 1

Second question is how do I use {lookup} value in the view?
You need two lookup_fields for the same set. You can do that by a custom Mixin class. But in four case, it is better not to use routers but custom urls, so edit like this:
# views.py
class BookViewSet(viewsets.ReadOnlyModelViewSet):
queryset = BookKeeper.objects.all()
serializer_class = BookSerializer
#action(detail=True)
def bycategory(self, request, category):
# do filtering by category
print(category)
#action(detail=True)
def byid(self, request, book_id):
# do filtering by book_id
print(book_id)
# urls.py
get_by_id = views.BookViewSet.as_view(
{
'get': 'byid'
}
)
get_by_category = views.BookViewSet.as_view(
{
'get': 'bycategory'
}
)
urlpatterns += [
url(
r'^api/books/byid/(?P<book_id>[0-9a-f-]+)/',
get_by_id,
name='get-by-id'
),url(
r'^api/books/bycategory/(?P<category>[0-9a-f-]+)/',
get_by_category,
name='get-by-category'
)
]