Support using the route decorator on view classes

CHANGES.rst

@@ -81,7 +81,8 @@ Unreleased
 -   ``helpers.total_seconds()`` is deprecated. Use
     ``timedelta.total_seconds()`` instead. :pr:`3962`
 -   Add type hinting. :pr:`3973`.
-
+-   Support using the ``route`` decorator on view classes (i.e.
+    ``View`` and ``MethodView`` subclasses). :issue:`3404`
 
 Version 1.1.2
 -------------

docs/views.rst

@@ -233,3 +233,56 @@ registration code::
                          methods=['GET', 'PUT', 'DELETE'])
 
     register_api(UserAPI, 'user_api', '/users/', pk='user_id')
+
+
+Use the ``route`` Decorator on View Classes
+-------------------------------------------
+
+For simple use cases, you can use the :func:`~flask.Flask.route` decorator
+as a shortcut of :meth:`~flask.views.View.as_view` class method to register
+a view class::
+
+    from flask.views import View
+
+    @app.route('/users/', endpoint='show_users')
+    class ShowUsers(View):
+
+        def dispatch_request(self):
+            users = User.query.all()
+            return render_template('users.html', objects=users)
+
+Or on a method-based view class::
+
+    from flask.views import MethodView
+
+    @app.route('/users/', endpoint='users')
+    class UserAPI(MethodView):
+
+        def get(self):
+            users = User.query.all()
+            ...
+
+        def post(self):
+            user = User.from_form_data(request.form)
+            ...
+
+You can also pass a view class to :meth:`~flask.Flask.add_url_rule`
+directly::
+
+    from flask.views import MethodView
+
+    class UserAPI(MethodView):
+
+        def get(self):
+            users = User.query.all()
+            ...
+
+        def post(self):
+            user = User.from_form_data(request.form)
+            ...
+
+    app.add_url_rule('/users/', endpoint='users', view_func=UserAPI)
+
+Beware that if the ``endpoint`` argument isn't provided, the class name
+will be used as the endpoint. Also, you can't pass any class arguments in
+this way.

src/flask/app.py

@@ -68,6 +68,8 @@ from .typing import TemplateGlobalCallable
 from .typing import TemplateTestCallable
 from .typing import URLDefaultCallable
 from .typing import URLValuePreprocessorCallable
+from .typing import ViewFuncArgument
+from .views import View
 from .wrappers import Request
 from .wrappers import Response
 
@@ -1033,10 +1035,16 @@ class Flask(Scaffold):
         self,
         rule: str,
         endpoint: t.Optional[str] = None,
-        view_func: t.Optional[t.Callable] = None,
+        view_func: ViewFuncArgument = None,
         provide_automatic_options: t.Optional[bool] = None,
         **options: t.Any,
     ) -> None:
+        """A helper method to register a rule (and optionally a view function)
+        to the application.
+
+        .. versionchanged:: 2.0.0
+            Support to pass a view class as view function.
+        """
         if endpoint is None:
             endpoint = _endpoint_from_view_func(view_func)  # type: ignore
         options["endpoint"] = endpoint
@@ -1078,6 +1086,8 @@ class Flask(Scaffold):
         rule.provide_automatic_options = provide_automatic_options  # type: ignore
 
         self.url_map.add(rule)
+        if isinstance(view_func, type) and issubclass(view_func, View):
+            view_func = view_func.as_view(endpoint)
         if view_func is not None:
             old_func = self.view_functions.get(endpoint)
             if getattr(old_func, "_flask_sync_wrapper", False):

src/flask/blueprints.py

@@ -15,6 +15,8 @@ from .typing import TemplateGlobalCallable
 from .typing import TemplateTestCallable
 from .typing import URLDefaultCallable
 from .typing import URLValuePreprocessorCallable
+from .typing import ViewFuncArgument
+from .views import View
 
 if t.TYPE_CHECKING:
     from .app import Flask
@@ -78,12 +80,15 @@ class BlueprintSetupState:
         self,
         rule: str,
         endpoint: t.Optional[str] = None,
-        view_func: t.Optional[t.Callable] = None,
+        view_func: ViewFuncArgument = None,
         **options: t.Any,
     ) -> None:
         """A helper method to register a rule (and optionally a view function)
         to the application.  The endpoint is automatically prefixed with the
         blueprint's name.
+
+        .. versionchanged:: 2.0.0
+            Support to pass a view class as view function.
         """
         if self.url_prefix is not None:
             if rule:
@@ -96,6 +101,8 @@ class BlueprintSetupState:
         defaults = self.url_defaults
         if "defaults" in options:
             defaults = dict(defaults, **options.pop("defaults"))
+        if isinstance(view_func, type) and issubclass(view_func, View):
+            view_func = view_func.as_view(endpoint)
         self.app.add_url_rule(
             rule,
             f"{self.name_prefix}{self.blueprint.name}.{endpoint}",

src/flask/scaffold.py

@@ -405,9 +405,9 @@ class Scaffold:
         return self._method_route("PATCH", rule, options)
 
     def route(self, rule: str, **options: t.Any) -> t.Callable:
-        """Decorate a view function to register it with the given URL
+        """Decorate a view function or view class to register it with
-        rule and options. Calls :meth:`add_url_rule`, which has more
+        the given URL rule and options. Calls :meth:`add_url_rule`, which
-        details about the implementation.
+        has more details about the implementation.
 
         .. code-block:: python
 
@@ -426,6 +426,9 @@ class Scaffold:
         :param rule: The URL rule string.
         :param options: Extra options passed to the
             :class:`~werkzeug.routing.Rule` object.
+
+        .. versionchanged:: 2.0.0
+            The ``route`` decorator can be used on view classes.
         """
 
         def decorator(f: t.Callable) -> t.Callable:

src/flask/typing.py

@@ -5,6 +5,7 @@ if t.TYPE_CHECKING:
     from werkzeug.datastructures import Headers  # noqa: F401
     from wsgiref.types import WSGIApplication  # noqa: F401
     from .wrappers import Response  # noqa: F401
+    from .views import View  # noqa: F401
 
 # The possible types that are directly convertible or are a Response object.
 ResponseValue = t.Union[
@@ -44,3 +45,4 @@ TemplateGlobalCallable = t.Callable[[], t.Any]
 TemplateTestCallable = t.Callable[[t.Any], bool]
 URLDefaultCallable = t.Callable[[str, dict], None]
 URLValuePreprocessorCallable = t.Callable[[t.Optional[str], t.Optional[dict]], None]
+ViewFuncArgument = t.Optional[t.Union[t.Callable, t.Type["View"]]]

tests/test_views.py

@@ -240,3 +240,55 @@ def test_remove_method_from_parent(app, client):
     assert client.get("/").data == b"GET"
     assert client.post("/").status_code == 405
     assert sorted(View.methods) == ["GET"]
+
+
+def test_route_on_view(app):
+    @app.route("/", endpoint="index")
+    class Index(flask.views.View):
+        methods = ["GET", "POST"]
+
+        def dispatch_request(self):
+            return flask.request.method
+
+    common_test(app)
+
+
+def test_route_on_methodview(app):
+    @app.route("/", endpoint="index")
+    class Index(flask.views.MethodView):
+        def get(self):
+            return "GET"
+
+        def post(self):
+            return "POST"
+
+    common_test(app)
+
+
+def test_bp_route_on_view(app):
+    bp = flask.Blueprint("test", __name__)
+
+    @bp.route("/", endpoint="index")
+    class Index(flask.views.View):
+        methods = ["GET", "POST"]
+
+        def dispatch_request(self):
+            return flask.request.method
+
+    app.register_blueprint(bp)
+    common_test(app)
+
+
+def test_bp_route_on_methodview(app):
+    bp = flask.Blueprint("test", __name__)
+
+    @bp.route("/", endpoint="index")
+    class Index(flask.views.MethodView):
+        def get(self):
+            return "GET"
+
+        def post(self):
+            return "POST"
+
+    app.register_blueprint(bp)
+    common_test(app)