add redirect method to app

CHANGES.rst

@@ -5,6 +5,9 @@ Version 2.2.0
 
 Unreleased
 
+-   Add an ``app.redirect`` method, which ``flask.redirect`` will call.
+    This makes it possible for an app to override how redirects work.
+    :issue:`4569`
 -   Refactor ``register_error_handler`` to consolidate error checking.
     Rewrite some error messages to be more consistent. :issue:`4559`
 

src/flask/__init__.py

@@ -1,7 +1,6 @@
 from markupsafe import escape
 from markupsafe import Markup
 from werkzeug.exceptions import abort as abort
-from werkzeug.utils import redirect as redirect
 
 from . import json as json
 from .app import Flask as Flask
@@ -23,6 +22,7 @@ from .helpers import flash as flash
 from .helpers import get_flashed_messages as get_flashed_messages
 from .helpers import get_template_attribute as get_template_attribute
 from .helpers import make_response as make_response
+from .helpers import redirect as redirect
 from .helpers import send_file as send_file
 from .helpers import send_from_directory as send_from_directory
 from .helpers import stream_with_context as stream_with_context

src/flask/app.py

@@ -22,6 +22,7 @@ from werkzeug.routing import MapAdapter
 from werkzeug.routing import RequestRedirect
 from werkzeug.routing import RoutingException
 from werkzeug.routing import Rule
+from werkzeug.utils import redirect as _wz_redirect
 from werkzeug.wrappers import Response as BaseResponse
 
 from . import cli
@@ -1630,6 +1631,16 @@ class Flask(Scaffold):
 
         return asgiref_async_to_sync(func)
 
+    def redirect(self, location: str, code: int = 302) -> BaseResponse:
+        """Create a redirect response object.
+
+        :param location: the url of the redirect
+        :param code: http return code
+
+        .. versionadded:: 2.2
+        """
+        return _wz_redirect(location, code=code, Response=self.response_class)
+
     def make_response(self, rv: ResponseReturnValue) -> Response:
         """Convert the return value from a view function to an instance of
         :attr:`response_class`.

src/flask/helpers.py

@@ -12,6 +12,7 @@ from threading import RLock
 import werkzeug.utils
 from werkzeug.routing import BuildError
 from werkzeug.urls import url_quote
+from werkzeug.utils import redirect as _wz_redirect
 
 from .globals import _app_ctx_stack
 from .globals import _request_ctx_stack
@@ -21,6 +22,7 @@ from .globals import session
 from .signals import message_flashed
 
 if t.TYPE_CHECKING:  # pragma: no cover
+    from werkzeug.wrappers import Response as BaseResponse
     from .wrappers import Response
 
 
@@ -340,6 +342,28 @@ def url_for(endpoint: str, **values: t.Any) -> str:
     return rv
 
 
+def redirect(
+    location: str, code: int = 302, Response: t.Optional[t.Type["BaseResponse"]] = None
+) -> "BaseResponse":
+    """Create a redirect response object.
+
+    If :data:`~flask.current_app` is available, it will use
+    :meth:`~flask.app.Flask.redirect`, otherwise it will use
+    :func:`werkzeug.utils.redirect`.
+
+    :param location: The URL to redirect to.
+    :param code: The status code for the redirect.
+    :param Response: The response class to use. Not used when
+        ``current_app`` is active, which uses ``app.response_class``.
+
+    .. versionadded:: 2.2
+    """
+    if current_app:
+        return current_app.redirect(location, code=code)
+
+    return _wz_redirect(location, code=code, Response=Response)
+
+
 def get_template_attribute(template_name: str, attribute: str) -> t.Any:
     """Loads a macro (or variable) a template exports.  This can be used to
     invoke a macro from within Python code.  If you for example have a

tests/test_helpers.py

@@ -158,6 +158,22 @@ class TestUrlFor:
         assert flask.url_for("myview", _method="POST") == "/myview/create"
 
 
+def test_redirect_no_app():
+    response = flask.redirect("https://localhost", 307)
+    assert response.location == "https://localhost"
+    assert response.status_code == 307
+
+
+def test_redirect_with_app(app):
+    def redirect(location, code=302):
+        raise ValueError
+
+    app.redirect = redirect
+
+    with app.app_context(), pytest.raises(ValueError):
+        flask.redirect("other")
+
+
 class TestNoImports:
     """Test Flasks are created without import.