Rest views

rest_framework/rest_views.py

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+from django import VERSION as DJANGO_VERSION
+from django.db import models
+from django.urls import path
+from django.utils.decorators import classonlymethod
+from django.views.decorators.csrf import csrf_exempt
+
+from rest_framework.views import APIView
+
+
+class RESTViewMethod:
+
+    def __init__(
+        self,
+        http_method: str,
+        path: str,
+        url_name: str,
+        view_method
+    ):
+        self.http_method = http_method
+        self.path = path
+        self.url_name = url_name
+        self.view_method = view_method
+
+
+def get(path: str, url_name: str):
+    def decorator(view_method):
+        return RESTViewMethod(
+            http_method='get',
+            path=path,
+            url_name=url_name,
+            view_method=view_method,
+        )
+
+    return decorator
+
+
+def post(path: str, url_name: str):
+    def decorator(view_method):
+        return RESTViewMethod(
+            http_method='post',
+            path=path,
+            url_name=url_name,
+            view_method=view_method,
+        )
+
+    return decorator
+
+
+def put(path: str, url_name: str):
+    def decorator(view_method):
+        return RESTViewMethod(
+            http_method='put',
+            path=path,
+            url_name=url_name,
+            view_method=view_method,
+        )
+
+    return decorator
+
+
+def patch(path: str, url_name: str):
+    def decorator(view_method):
+        return RESTViewMethod(
+            http_method='patch',
+            path=path,
+            url_name=url_name,
+            view_method=view_method,
+        )
+
+    return decorator
+
+
+def delete(path: str, url_name: str):
+    def decorator(view_method):
+        return RESTViewMethod(
+            http_method='delete',
+            path=path,
+            url_name=url_name,
+            view_method=view_method,
+        )
+
+    return decorator
+
+
+class RESTViewMetaclass(type):
+
+    def __new__(cls, name, bases, attrs):
+        _all_actions: dict[str, list[tuple[str, str, str]]] = {}
+        http_method_path_pairs = set()
+        url_names_by_path = {}
+
+        for key, value in attrs.items():
+            if isinstance(value, RESTViewMethod):
+                if (value.http_method, value.path) in http_method_path_pairs:
+                    raise ValueError(f"{cls.__name__} has multiple methods with the same HTTP method and path")
+
+                http_method_path_pairs.add((value.http_method, value.path))
+
+                url_names_by_path.setdefault(value.path, set()).add(value.url_name)
+                if len(url_names_by_path[value.path]) > 1:
+                    raise ValueError(
+                        f"{cls.__name__} has multiple methods with the same path {value.path}, but different URL names"
+                    )
+
+                http_method_path_pairs.add((value.http_method, value.path))
+                _all_actions.setdefault(value.path, [])
+                _all_actions[value.path].append((value.http_method, value.view_method.__name__, value.url_name))
+                attrs[key] = value.view_method
+
+        attrs['_all_actions'] = _all_actions
+        return type.__new__(cls, name, bases, attrs)
+
+
+class RESTView(APIView, metaclass=RESTViewMetaclass):
+    """
+    A View that allows handling any HTTP methods and URL paths. Use special decorators to specify URl path
+    and URl name for handlers. These decorators moved to a class attribute at runtime.
+
+    Example:
+        class UserAPI(RESTView):
+
+            @get(path='v1/users/', url_name='users')
+            def list(self, request):
+                ...
+
+            @get(path='v1/users/<int:user_id>/', url_name='user_detail')
+            def retrieve(self, request, user_id: int):
+                ...
+
+            @post(path='v1/users/', url_name='users')
+            def create(self, request):
+                ...
+
+            @patch(path='v1/users/<int:user_id>/change_password/', url_name='user_change_password')
+            def change_password(self, request, user_id: int):
+                ...
+
+    To use this View, you have to comply with these rules:
+    1. Use special decorators for all handlers
+    2. All identical URL paths must have identical URL names
+    3. Special decorators have to be the last in order
+    4. All custom decorators have to be wrapped with functools.wraps or manually copy the docstrings
+    """
+
+    @classonlymethod
+    def unwrap_url_patterns(cls, **initkwargs):
+        """
+        Create classes for all URL paths for Django urlpatterns interface
+
+        Example:
+            urlpatterns = [
+                *UserAPI.unwrap_url_patterns(),
+            ]
+        """
+        urlpatterns = []
+        for url_path, attrs in cls._all_actions.items():
+            view = cls.as_view(url_path=url_path, **initkwargs)
+            urlpatterns.append(path(url_path, view, name=attrs[0][2]))
+
+        return urlpatterns
+
+    @classmethod
+    def as_view(cls, url_path: str, **initkwargs):
+        """
+        Store the generated class on the view function for URL path. Don't use this method.
+        """
+        if isinstance(getattr(cls, 'queryset', None), models.query.QuerySet):
+            def force_evaluation():
+                raise RuntimeError(
+                    'Do not evaluate the `.queryset` attribute directly, '
+                    'as the result will be cached and reused between requests. '
+                    'Use `.all()` or call `.get_queryset()` instead.'
+                )
+            cls.queryset._fetch_all = force_evaluation
+
+        fork_cls = type(cls.__name__, cls.__bases__, dict(cls.__dict__))
+        actions = {}
+        for http_method, view_method_name, url_name in cls._all_actions[url_path]:
+            actions[http_method] = view_method_name
+
+        if 'get' in actions and 'head' not in actions:
+            actions['head'] = actions['get']
+
+        if 'options' not in actions:
+            # use ApiView.options
+            actions['options'] = 'options'
+
+        fork_cls.actions = actions
+        view = super(APIView, fork_cls).as_view(**initkwargs)
+        view.cls = fork_cls
+        view.initkwargs = initkwargs
+
+        # Exempt all DRF views from Django's LoginRequiredMiddleware. Users should set
+        # DEFAULT_PERMISSION_CLASSES to 'rest_framework.permissions.IsAuthenticated' instead
+        if DJANGO_VERSION >= (5, 1):
+            view.login_required = False
+
+        # Note: session based authentication is explicitly CSRF validated,
+        # all other authentication is CSRF exempt.
+        return csrf_exempt(view)
+
+    def dispatch(self, request, *args, **kwargs):
+        """
+        `.dispatch()` is pretty much the same as ApiView dispatch
+        """
+        self.args = args
+        self.kwargs = kwargs
+        request = self.initialize_request(request, *args, **kwargs)
+        self.request = request
+        self.headers = self.default_response_headers  # deprecate?
+
+        try:
+            self.initial(request, *args, **kwargs)
+
+            view_method_name = self.actions.get(request.method.lower())
+            handler = (
+                getattr(self, view_method_name, self.http_method_not_allowed)
+                if view_method_name
+                else self.http_method_not_allowed
+            )
+            response = handler(request, *args, **kwargs)
+
+        except Exception as exc:
+            response = self.handle_exception(exc)
+
+        self.response = self.finalize_response(request, response, *args, **kwargs)
+        return self.response
+
+
+__all__ = ['get', 'post', 'put', 'patch', 'delete', 'RESTView']

tests/test_rest_views.py

@@ -0,0 +1,148 @@
+from functools import wraps
+
+from django.test import TestCase, override_settings
+
+from rest_framework import status
+from rest_framework.response import Response
+from rest_framework.rest_views import RESTView, get, patch, post
+from rest_framework.settings import api_settings
+
+
+class BasicRESTView(RESTView):
+
+    @get(path='instances/', url_name='instances_list')
+    def list(self, request):
+        return Response(status=200, data={'http_method': 'GET', 'view_method': 'list'})
+
+    @get(path='instances/<int:instance_id>/', url_name='detail_instance')
+    def retrieve(self, request, instance_id: int):
+        return Response(status=200, data={'http_method': 'GET', 'view_method': 'retrieve'})
+
+    @post(path='instances/', url_name='instances_list')
+    def create(self, request):
+        return Response(status=201, data={'http_method': 'POST', 'view_method': 'create'})
+
+    @patch(path='instances/<int:instance_id>/', url_name='detail_instance')
+    def update(self, request, instance_id: int):
+        return Response(status=200, data={'http_method': 'PATCH', 'view_method': 'update'})
+
+    @patch(path='instances/<int:instance_id>/change/', url_name='detail_instance_change')
+    def change_status(self, request, instance_id: int):
+        return Response(status=200, data={'http_method': 'PATCH', 'view_method': 'change_status'})
+
+
+class ErrorRESTView(RESTView):
+
+    @get(path='errors/', url_name='errors_list')
+    def error_method(self, request):
+        raise Exception
+
+
+def custom_decorator(view_method):
+    @wraps(view_method)
+    def wrapper(*args, **kwargs):
+        response = view_method(*args, **kwargs)
+        response.data['has_decorator'] = True
+        return response
+
+    return wrapper
+
+
+class RESTViewWithCustomDecorators(RESTView):
+
+    @get(path='decorators/', url_name='errors_list')
+    @custom_decorator
+    def custom_decorator(self, request):
+        return Response(status=200, data={'http_method': 'GET', 'view_method': 'custom_decorator'})
+
+
+urlpatterns = [
+    *BasicRESTView.unwrap_url_patterns(),
+    *ErrorRESTView.unwrap_url_patterns(),
+    *RESTViewWithCustomDecorators.unwrap_url_patterns(),
+]
+
+
+class TestInitializeRESTView(TestCase):
+
+    @staticmethod
+    def test_initialize_rest_view():
+        assert BasicRESTView._all_actions == {
+            'instances/': [
+                ('get', 'list', 'instances_list'),
+                ('post', 'create', 'instances_list'),
+            ],
+            'instances/<int:instance_id>/': [
+                ('get', 'retrieve', 'detail_instance'),
+                ('patch', 'update', 'detail_instance'),
+            ],
+            'instances/<int:instance_id>/change/': [('patch', 'change_status', 'detail_instance_change')],
+        }
+        assert not hasattr(BasicRESTView, 'actions')
+
+
+class TestRESTViewUnwrap(TestCase):
+
+    @staticmethod
+    def test_unwrap_url_patterns():
+        urlpatterns = BasicRESTView.unwrap_url_patterns()
+        assert len(urlpatterns) == 3
+        for pattern in urlpatterns:
+            assert pattern.callback.cls is not BasicRESTView
+
+
+@override_settings(ROOT_URLCONF='tests.test_rest_views')
+class RESTViewIntegrationTests(TestCase):
+
+    def test_successful_get_request(self):
+        response = self.client.get(path='/instances/')
+        assert response.status_code == status.HTTP_200_OK
+        assert response.data == {'http_method': 'GET', 'view_method': 'list'}
+
+    def test_successful_get_request_with_path_param(self):
+        response = self.client.get(path='/instances/1/')
+        assert response.status_code == status.HTTP_200_OK
+        assert response.data == {'http_method': 'GET', 'view_method': 'retrieve'}
+
+    def test_successful_post_request(self):
+        response = self.client.post(path='/instances/')
+        assert response.status_code == status.HTTP_201_CREATED
+        assert response.data == {'http_method': 'POST', 'view_method': 'create'}
+
+    def test_successful_head_request(self):
+        response = self.client.head(path='/instances/')
+        assert response.status_code == status.HTTP_200_OK
+        assert response.data == {'http_method': 'GET', 'view_method': 'list'}
+
+    def test_successful_options_request(self):
+        response = self.client.options(path='/instances/')
+        assert response.status_code == status.HTTP_200_OK
+
+    def test_method_not_allowed(self):
+        response = self.client.put(path='/instances/')
+        assert response.status_code == status.HTTP_405_METHOD_NOT_ALLOWED
+
+    def test_method_with_custom_decorator(self):
+        response = self.client.get(path='/decorators/')
+        assert response.status_code == status.HTTP_200_OK
+        assert response.data == {'http_method': 'GET', 'view_method': 'custom_decorator', 'has_decorator': True}
+
+
+@override_settings(ROOT_URLCONF='tests.test_rest_views')
+class TestCustomExceptionHandler(TestCase):
+
+    def setUp(self):
+        self.DEFAULT_HANDLER = api_settings.EXCEPTION_HANDLER
+
+        def exception_handler(exc, request):
+            return Response('Error!', status=status.HTTP_400_BAD_REQUEST)
+
+        api_settings.EXCEPTION_HANDLER = exception_handler
+
+    def tearDown(self):
+        api_settings.EXCEPTION_HANDLER = self.DEFAULT_HANDLER
+
+    def test_class_based_view_exception_handler(self):
+        response = self.client.get(path='/errors/')
+        assert response.status_code == status.HTTP_400_BAD_REQUEST
+        assert response.data == 'Error!'