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Pagination in Django-Rest-Framework with API-View

It is necessary to display the configured 10 records per swagger page (book api).
The BookListView class in views.py looks like this:
class BookListView(APIView):
def get(self, request):
author = set([item.get('ID') for item in Author.objects.values('ID').all()])
saler = set([item.get('name') for item in Saler.objects.values('name').all()])
if author:
salers = Saler.objects.filter(name__in=list(saler - author))
else:
salers = Saler.objects.all()
serializer = SalerListSerializer(salers, many = True)
return Response(serializer.data)
Now all records are displayed at once, I would like to add pangination and display 10 records on one page.
I added 'DEFAULT_PAGINATION_CLASS': 'rest_framework.pagination.DESIRED_PAGINATION_STYLE', 'PAGE_SIZE': 100 to the settings.py file, but since I am using APIView, this does not work.
What is the way to implement the idea?

You need to call your paginator's paginate_queryset method. Since you're using a APIView, it does not have many of the built-in functions to do this for you, but the process is as follows:
Instantiate a paginator:
from rest_framework.settings import api_settings
pagination_class = api_settings.DEFAULT_PAGINATION_CLASS
paginator = pagination_class()
Get a page from your queryset and serialize it:
page = paginator.paginate_queryset(queryset, request, view=self)
serializer = self.get_serializer(page, many=True)
Return a paginated response:
return paginator.get_paginated_response(serializer.data)
This is how django-rest does it with its ListAPIView class. You can go though the code easily by checking out the ListAPIView's list method here.
However, I suggest using a ListAPIView instead of an APIView since it already handles
pagination for you.

Django-REST: custom permission doesn't work

I'm trying to make a custom permission using this guide
views.py
class CustomModelList(generics.ListAPIView):
queryset = CustomModel.objects.all()
serializer_class = CustomModelSerializer
permission_classes = [IsAuthenticatedOrReadOnly, IsCustomOrReadOnly]
def get(self, request, format=None):
# some logic
def post(self, request, format=None):
# some logic
Just for experiment I've created this permission not to apply anyway
pesmissions.py
class IsCustomOrReadOnly(BasePermission):
def has_object_permission(self, request, view, obj):
return False
But when POST request sends to server it takes no effect -- I'm able to create new model instance.

I think that since you are using a list view, custom object level permissions are not checked automatically.
Also note that the generic views will only check the object-level permissions for views that retrieve a single model instance. If you require object-level filtering of list views, you'll need to filter the queryset separately. See the filtering documentation for more details.
You can try overriding the has_permission method instead and see if that works, or check the permissions manually.

One object only in GET method in Django REST Framework

I have a list of all my objects when I use get method by api/movies in my api, and this is ok. I want also to get only one, specyfic object when use get method by api/movies/1 but now I still have a list of all my objects... What to change in my MoviesView or in urls?
My views.py:
class MoviesView(APIView):
def get(self, request):
movies = Movie.objects.all()
serializer = MovieSerializer(movies, many=True)
return Response(serializer.data)
My appurls.py:
urlpatterns = [
url('movies', MoviesView.as_view(), name="MoviesView"),
]
And my project urls.py:
urlpatterns = [
path('admin/', admin.site.urls),
path('api/', include("api.urls")),
]
When I use routers everythig crushes... Could you help me?

You can simply use viewsets.ModelViewSet that natively implements list and retrieve.
You declare something like router.register('movies', my_views.MoviesViewSet) in you urls.py and
class MoviesViewSet(viewsets.ModelViewSet):
queryset = Movie.objects.all()
serializer_class = MovieSerializer
permission_classes = [IsAuthenticated, ]
def get_queryset(self):
return self.queryset
def get_object(self):
movie_id = self.kwargs['pk']
return self.get_queryset().filter(id=movie_id)
def retrieve(self, request, *args, **kwargs):
try:
instance = self.get_object()
except (Movie.DoesNotExist, KeyError):
return Response({"error": "Requested Movie does not exist"}, status=status.HTTP_404_NOT_FOUND)
serializer = self.get_serializer(instance)
return Response(serializer.data)
def list(self, request, *args, **kwargs):
queryset = self.get_queryset()
serializer = self.get_serializer(queryset, many=True)
return Response(serializer.data)
This approach implies that you declare a Serializer, just like:
class MovieSerializer(serializers.ModelSerializer):
class Meta:
model = Movie
fields = '__all__'
Django simply maps HOST/movies/ to list (multiple objects) and HOST/movies/PK/ to retrieve method (one single object).
Docs:
https://www.django-rest-framework.org/api-guide/viewsets/#modelviewset
https://www.django-rest-framework.org/api-guide/serializers/#modelserializer
Hope it helps.
BR.
Eduardo

I would suggest you if you want to retrieve just 1 element to use a Generic View, i.e RetrieveAPIView
It would give you all you need for getting 1 element.
from rest_framework import generics
class MoviesView(generics.RetrieveAPIView):
queryset = Movie.objects.all()
serializer_class = MovieSerializer
but you need also to change urls.py
url(r'movies/(?P<pk>[0-9]+)/$', MoviesView.as_view(), name="MoviesView"),

When you make a GET request to "api/movies/1", the url is matched to the "api/movies" path (read more in the docs), and the MoviesView's get method is called. And your get() implementation just fetches all the movies (movies = Movie.objects.all()), serializes and returns them - that's why you get the entire list.
If you want to retrieve one specific object, you need to somehow specify which object you have in mind, using its primary key (in your case, id).
1. You have to define a separate path: movies/<int:pk>/ (btw, which Django version are you using? url has been deprecated, use path instead!)
2. You have to define a detail view to handle this new case, and pass it to the path function as the second argument.
This general problem can really be solved in many ways, and depending on your app you may want to use a ViewSet instead of views. Then you don't have to define paths (urls) separately - you can use a router. You can't use routers with your view, because router needs a viewset class as its argument.
If you provide more details, I could try to suggest something more specific.

My appurls.py:
use path method
urlpatterns = [
path('movies', MoviesView.as_view(), name="MoviesView"),]
Maybe it works

Start by adding a format keyword argument to both of the views, like so
def snippet_list(request, format=None):
and
def snippet_detail(request, pk, format=None):
Now update the snippets/urls.py file slightly, to append a set of format_suffix_patterns in addition to the existing URLs
from django.urls import path
from rest_framework.urlpatterns import format_suffix_patterns
from snippets import views
urlpatterns = [
path('snippets/', views.snippet_list),
path('snippets/<int:pk>', views.snippet_detail),
]
urlpatterns = format_suffix_patterns(urlpatterns)

Django POST with ModelViewSet and ModelSerializer 405

How can I make a ModelViewSet accept the POST method to create an object? When I attempt to call the endpoint I get a 405 'Method "POST" not allowed.'.
Within views.py:
class AccountViewSet(viewsets.ModelViewSet):
"""An Account ModelViewSet."""
model = Account
serializer_class = AccountSerializer
queryset = Account.objects.all().order_by('name')
Within serializers.py:
class AccountSerializer(serializers.ModelSerializer):
name = serializers.CharField(required=False)
active_until = serializers.DateTimeField()
class Meta:
model = Account
fields = [
'name',
'active_until',
]
def create(self, validated_data):
with transaction.atomic():
Account.objects.create(**validated_data)
within urls.py:
from rest_framework import routers
router = routers.SimpleRouter()
router.register(
prefix=r'v1/auth/accounts',
viewset=AccountViewSet,
base_name='accounts',
)
Do I need to create a specific #action? my attempts to do so have yet to be successful. If that is the case what would the url = reverse('app:accounts-<NAME>') be such that I can call it from tests? I haven't found a full example (urls.py, views.py, serializers.py, and tests etc).

I discovered what the issue was, I had a conflicting route. There was a higher level endpoint registered before the AccountViewSet.
router.register(
prefix=r'v1/auth',
viewset=UserViewSet,
base_name='users',
)
router.register(
prefix=r'v1/auth/accounts',
viewset=AccountViewSet,
base_name='accounts',
)
Django runs through each URL pattern, in order, and stops at the first one that matches the requested URL.. I should have been ordered this way:
router.register(
prefix=r'v1/auth/accounts',
viewset=AccountViewSet,
base_name='accounts',
)
router.register(
prefix=r'v1/auth',
viewset=UserViewSet,
base_name='users',
)
despite the fact that reverse('appname:acccounts-list') worked, the underlying URL router still thought I was calling the UserViewSet.

From the docs:
A ViewSet class is simply a type of class-based View, that does not provide any method handlers such as .get() or .post(), and instead provides actions such as .list() and .create().
And here is a list of supported actions:
def list(self, request):
pass
def create(self, request):
pass
def retrieve(self, request, pk=None):
pass
def update(self, request, pk=None):
pass
def partial_update(self, request, pk=None):
pass
def destroy(self, request, pk=None):
pass
So no post is not directly supported but create is.
So your end point would be v1/auth/accounts/create when using the a router instead v1/auth/accounts/post.
I honestly prefer using class based or function based views when working with DRF. It resembles regular django views more closely and makes more sense to me when working with them. You woul write you views and urls pretty much like regular django urls and views.

Django REST Framework - can't override list in ListAPIView

I am using Django REST Framework to create an endpoint that will produce a PDF document. The PDF document will have information that corresponds to a particular Department. I have two desired functionalities -- to be able to download a PDF document, and to be able to preview the document within the browser.
Since the PDF document changes over time based on data that is added to the app, the document needs to be generated in real time when it is requested. As a first step, I'm trying to have the document be generated in a remote file storage location when the following endpoint is hit by a GET request:
departments/<department_pk>/result/preview
Since my endpoint should only take GET requests, I am using a ListAPIView. I'm trying to override the list method so that my custom document generation logic is executed, but it looks like the method is never called. How can I have some custom document generation logic be inserted into my endpoint, so that it is executed when the endpoint is hit by a GET request?
api/urls.py
url(r'^departments/(?P<department_pk>[0-9]+)/result/preview',
include(result_document_urls.result_document_preview_router.urls,
document_app/urls.py
result_document_preview_router = routers.DefaultRouter()
result_document_preview_router.register(r'^', ResultDocumentDetailView.as_view(),
base_name='Department')
document_app/views.py
class ResultDocumentDetailView(generics.ListAPIView):
queryset = Department.objects.all()
lookup_field = 'department_pk'
lookup_url_kwarg = 'department_pk'
def list(self, request, department_pk):
queryset = self.get_queryset()
import ipdb; ipdb.set_trace() # this break point is never hit
department = get_object_or_404(queryset, department_pk=department_pk)
...generate document logic...
return Response(status=status.HTTP_200_OK)

replace list method with below code, I think it will work
class ResultDocumentDetailView(generics.ListAPIView):
queryset = Department.objects.all()
lookup_field = 'department_pk'
lookup_url_kwarg = 'department_pk'
def list(self, request, *args, **kwargs):
queryset = self.get_queryset()
import ipdb; ipdb.set_trace() # this break point is never hit
department = get_object_or_404(
queryset, department_pk=kwargs.get('department_pk')
)
...generate document logic...
return Response(status=status.HTTP_200_OK)
for more reference see the overrinding method "list"
https://github.com/tomchristie/django-rest-framework/blob/master/rest_framework/mixins.py#L35

In your document_app/urls.py, you are incorrectly passing ResultDocumentDetailView as an argument instead of a viewset.
Router while registering accepts a ViewSet instead of an APIView.
There are two mandatory arguments to the register() method:
prefix - The URL prefix to use for this set of routes.
viewset - The viewset class.
Also, since you are only interested in the retrieve method, you can just create a ResultDocumentRetrieveView and add its corresponding url to your urls.py without the need of creating a ResultDocument router. (Routers are generally used when you want to handle both list and detail requests.)
class ResultDocumentRetrieveView(generics.RetrieveAPIView):
queryset = Department.objects.all()
lookup_field = 'department_pk'
lookup_url_kwarg = 'department_pk'
def retrieve(self, request, department_pk):
department = self.get_object()
...generate document logic...
return Response(status=status.HTTP_200_OK)
urls.py
url(r'^departments/(?P<department_pk>[0-9]+)/result/preview', ResultDocumentRetrieveView.as_view())