Pass the request ctx rather than use the globals in the app

The globals have a performance penalty which can be justified for the
convinience in user code. In the app however the ctx can easily be
passed through the method calls thereby reducing the performance
penalty.

This may affect extensions if they have subclassed the app and
overridden these methods.

CHANGES.rst

@@ -6,7 +6,8 @@ Unreleased
 -   Remove previously deprecated code. :pr:`5223`
 -   Restructure the code such that the Flask (app) and Blueprint
     classes have Sans-IO bases. :pr:`5127`
-
+-   Pass the request ctx rather than use the globals in the app class
+    methods. :pr:`5229`
 
 Version 2.3.3
 -------------

src/flask/app.py

@@ -692,12 +692,17 @@ def test_cli_runner(self, **kwargs: t.Any) -> FlaskCliRunner:
         return cls(self, **kwargs)  # type: ignore
 
     def handle_http_exception(
-        self, e: HTTPException
+        self,
+        e: HTTPException,
+        ctx: RequestContext,
     ) -> HTTPException | ft.ResponseReturnValue:
         """Handles an HTTP exception.  By default this will invoke the
         registered error handlers and fall back to returning the
         exception as response.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         .. versionchanged:: 1.0.3
             ``RoutingException``, used internally for actions such as
              slash redirects during routing, is not passed to error
@@ -721,13 +726,15 @@ def handle_http_exception(
         if isinstance(e, RoutingException):
             return e
 
-        handler = self._find_error_handler(e, request.blueprints)
+        handler = self._find_error_handler(e, ctx.request.blueprints)
         if handler is None:
             return e
         return self.ensure_sync(handler)(e)
 
     def handle_user_exception(
-        self, e: Exception
+        self,
+        e: Exception,
+        ctx: RequestContext,
     ) -> HTTPException | ft.ResponseReturnValue:
         """This method is called whenever an exception occurs that
         should be handled. A special case is :class:`~werkzeug
@@ -736,6 +743,9 @@ def handle_user_exception(
         return a response value or reraise the exception with the same
         traceback.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         .. versionchanged:: 1.0
             Key errors raised from request data like ``form`` show the
             bad key in debug mode rather than a generic bad request
@@ -749,16 +759,16 @@ def handle_user_exception(
             e.show_exception = True
 
         if isinstance(e, HTTPException) and not self.trap_http_exception(e):
-            return self.handle_http_exception(e)
+            return self.handle_http_exception(e, ctx)
 
-        handler = self._find_error_handler(e, request.blueprints)
+        handler = self._find_error_handler(e, ctx.request.blueprints)
 
         if handler is None:
             raise
 
         return self.ensure_sync(handler)(e)
 
-    def handle_exception(self, e: Exception) -> Response:
+    def handle_exception(self, e: Exception, ctx: RequestContext) -> Response:
         """Handle an exception that did not have an error handler
         associated with it, or that was raised from an error handler.
         This always causes a 500 ``InternalServerError``.
@@ -775,6 +785,9 @@ def handle_exception(self, e: Exception) -> Response:
         always receive the ``InternalServerError``. The original
         unhandled exception is available as ``e.original_exception``.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         .. versionchanged:: 1.1.0
             Always passes the ``InternalServerError`` instance to the
             handler, setting ``original_exception`` to the unhandled
@@ -801,77 +814,87 @@ def handle_exception(self, e: Exception) -> Response:
 
             raise e
 
-        self.log_exception(exc_info)
+        self.log_exception(exc_info, ctx)
         server_error: InternalServerError | ft.ResponseReturnValue
         server_error = InternalServerError(original_exception=e)
-        handler = self._find_error_handler(server_error, request.blueprints)
+        handler = self._find_error_handler(server_error, ctx.request.blueprints)
 
         if handler is not None:
             server_error = self.ensure_sync(handler)(server_error)
 
-        return self.finalize_request(server_error, from_error_handler=True)
+        return self.finalize_request(server_error, ctx, from_error_handler=True)
 
     def log_exception(
         self,
         exc_info: (tuple[type, BaseException, TracebackType] | tuple[None, None, None]),
+        ctx: RequestContext,
     ) -> None:
         """Logs an exception.  This is called by :meth:`handle_exception`
         if debugging is disabled and right before the handler is called.
         The default implementation logs the exception as error on the
         :attr:`logger`.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         .. versionadded:: 0.8
         """
         self.logger.error(
-            f"Exception on {request.path} [{request.method}]", exc_info=exc_info
+            f"Exception on {ctx.request.path} [{ctx.request.method}]", exc_info=exc_info
         )
 
-    def dispatch_request(self) -> ft.ResponseReturnValue:
+    def dispatch_request(self, ctx: RequestContext) -> ft.ResponseReturnValue:
         """Does the request dispatching.  Matches the URL and returns the
         return value of the view or error handler.  This does not have to
         be a response object.  In order to convert the return value to a
         proper response object, call :func:`make_response`.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         .. versionchanged:: 0.7
            This no longer does the exception handling, this code was
            moved to the new :meth:`full_dispatch_request`.
         """
-        req = request_ctx.request
-        if req.routing_exception is not None:
-            self.raise_routing_exception(req)
-        rule: Rule = req.url_rule  # type: ignore[assignment]
+        if ctx.request.routing_exception is not None:
+            self.raise_routing_exception(ctx.request)
+        rule: Rule = ctx.request.url_rule  # type: ignore[assignment]
         # if we provide automatic options for this URL and the
         # request came with the OPTIONS method, reply automatically
         if (
             getattr(rule, "provide_automatic_options", False)
-            and req.method == "OPTIONS"
+            and ctx.request.method == "OPTIONS"
         ):
             return self.make_default_options_response()
         # otherwise dispatch to the handler for that endpoint
-        view_args: dict[str, t.Any] = req.view_args  # type: ignore[assignment]
+        view_args: dict[str, t.Any] = ctx.request.view_args  # type: ignore[assignment]
         return self.ensure_sync(self.view_functions[rule.endpoint])(**view_args)
 
-    def full_dispatch_request(self) -> Response:
+    def full_dispatch_request(self, ctx: RequestContext) -> Response:
         """Dispatches the request and on top of that performs request
         pre and postprocessing as well as HTTP exception catching and
         error handling.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         .. versionadded:: 0.7
         """
         self._got_first_request = True
 
         try:
             request_started.send(self, _async_wrapper=self.ensure_sync)
-            rv = self.preprocess_request()
+            rv = self.preprocess_request(ctx)
             if rv is None:
-                rv = self.dispatch_request()
+                rv = self.dispatch_request(ctx)
         except Exception as e:
-            rv = self.handle_user_exception(e)
-        return self.finalize_request(rv)
+            rv = self.handle_user_exception(e, ctx)
+        return self.finalize_request(rv, ctx)
 
     def finalize_request(
         self,
         rv: ft.ResponseReturnValue | HTTPException,
+        ctx: RequestContext,
         from_error_handler: bool = False,
     ) -> Response:
         """Given the return value from a view function this finalizes
@@ -884,11 +907,14 @@ def finalize_request(
         with the `from_error_handler` flag.  If enabled, failures in
         response processing will be logged and otherwise ignored.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         :internal:
         """
         response = self.make_response(rv)
         try:
-            response = self.process_response(response)
+            response = self.process_response(response, ctx)
             request_finished.send(
                 self, _async_wrapper=self.ensure_sync, response=response
             )
@@ -1215,7 +1241,7 @@ def make_response(self, rv: ft.ResponseReturnValue) -> Response:
 
         return rv
 
-    def preprocess_request(self) -> ft.ResponseReturnValue | None:
+    def preprocess_request(self, ctx: RequestContext) -> ft.ResponseReturnValue | None:
         """Called before the request is dispatched. Calls
         :attr:`url_value_preprocessors` registered with the app and the
         current blueprint (if any). Then calls :attr:`before_request_funcs`
@@ -1224,13 +1250,16 @@ def preprocess_request(self) -> ft.ResponseReturnValue | None:
         If any :meth:`before_request` handler returns a non-None value, the
         value is handled as if it was the return value from the view, and
         further request handling is stopped.
+
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
         """
-        names = (None, *reversed(request.blueprints))
+        names = (None, *reversed(ctx.request.blueprints))
 
         for name in names:
             if name in self.url_value_preprocessors:
                 for url_func in self.url_value_preprocessors[name]:
-                    url_func(request.endpoint, request.view_args)
+                    url_func(ctx.request.endpoint, ctx.request.view_args)
 
         for name in names:
             if name in self.before_request_funcs:
@@ -1242,11 +1271,14 @@ def preprocess_request(self) -> ft.ResponseReturnValue | None:
 
         return None
 
-    def process_response(self, response: Response) -> Response:
+    def process_response(self, response: Response, ctx: RequestContext) -> Response:
         """Can be overridden in order to modify the response object
         before it's sent to the WSGI server.  By default this will
         call all the :meth:`after_request` decorated functions.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         .. versionchanged:: 0.5
            As of Flask 0.5 the functions registered for after request
            execution are called in reverse order of registration.
@@ -1255,23 +1287,25 @@ def process_response(self, response: Response) -> Response:
         :return: a new response object or the same, has to be an
                  instance of :attr:`response_class`.
         """
-        ctx = request_ctx._get_current_object()  # type: ignore[attr-defined]
-
         for func in ctx._after_request_functions:
             response = self.ensure_sync(func)(response)
 
-        for name in chain(request.blueprints, (None,)):
+        for name in chain(ctx.request.blueprints, (None,)):
             if name in self.after_request_funcs:
                 for func in reversed(self.after_request_funcs[name]):
                     response = self.ensure_sync(func)(response)
 
         if not self.session_interface.is_null_session(ctx.session):
-            self.session_interface.save_session(self, ctx.session, response)
+            self.session_interface.save_session(
+                self, ctx.session, response  # type: ignore[arg-type]
+            )
 
         return response
 
     def do_teardown_request(
-        self, exc: BaseException | None = _sentinel  # type: ignore
+        self,
+        ctx: RequestContext,
+        exc: BaseException | None = _sentinel,  # type: ignore
     ) -> None:
         """Called after the request is dispatched and the response is
         returned, right before the request context is popped.
@@ -1290,13 +1324,16 @@ def do_teardown_request(
             request. Detected from the current exception information if
             not passed. Passed to each teardown function.
 
+        .. versionchanged:: 3.0
+            The request context, ctx, is now a required argument.
+
         .. versionchanged:: 0.9
             Added the ``exc`` argument.
         """
         if exc is _sentinel:
             exc = sys.exc_info()[1]
 
-        for name in chain(request.blueprints, (None,)):
+        for name in chain(ctx.request.blueprints, (None,)):
             if name in self.teardown_request_funcs:
                 for func in reversed(self.teardown_request_funcs[name]):
                     self.ensure_sync(func)(exc)
@@ -1451,10 +1488,10 @@ def wsgi_app(self, environ: dict, start_response: t.Callable) -> t.Any:
         try:
             try:
                 ctx.push()
-                response = self.full_dispatch_request()
+                response = self.full_dispatch_request(ctx)
             except Exception as e:
                 error = e
-                response = self.handle_exception(e)
+                response = self.handle_exception(e, ctx)
             except:  # noqa: B001
                 error = sys.exc_info()[1]
                 raise

src/flask/ctx.py

@@ -398,7 +398,7 @@ def pop(self, exc: BaseException | None = _sentinel) -> None:  # type: ignore
             if clear_request:
                 if exc is _sentinel:
                     exc = sys.exc_info()[1]
-                self.app.do_teardown_request(exc)
+                self.app.do_teardown_request(self, exc)
 
                 request_close = getattr(self.request, "close", None)
                 if request_close is not None:

tests/test_reqctx.py

@@ -288,8 +288,8 @@ def test_bad_environ_raises_bad_request():
     # use a non-printable character in the Host - this is key to this test
     environ["HTTP_HOST"] = "\x8a"
 
-    with app.request_context(environ):
-        response = app.full_dispatch_request()
+    with app.request_context(environ) as ctx:
+        response = app.full_dispatch_request(ctx)
     assert response.status_code == 400
 
 
@@ -308,8 +308,8 @@ def index():
     # these characters are all IDNA-compatible
     environ["HTTP_HOST"] = "ąśźäüжŠßя.com"
 
-    with app.request_context(environ):
-        response = app.full_dispatch_request()
+    with app.request_context(environ) as ctx:
+        response = app.full_dispatch_request(ctx)
 
     assert response.status_code == 200
 

tests/test_subclassing.py

@@ -5,7 +5,7 @@
 
 def test_suppressed_exception_logging():
     class SuppressedFlask(flask.Flask):
-        def log_exception(self, exc_info):
+        def log_exception(self, exc_info, ctx):
             pass
 
     out = StringIO()