Add query() route shortcut and MethodView support for HTTP QUERY

CHANGES.rst

@@ -28,6 +28,9 @@ Unreleased
     it's disabled in config. Previously, only disabling worked. :issue:`5916`
 -   ``Flask.select_jinja_autoescape`` uses case-insensitive comparison instead
     of only lower case file extensions. :pr:`6012`
+-   Add ``query`` method route shortcut for the ``QUERY`` HTTP method
+    (:rfc:`10008`). ``MethodView`` dispatches ``QUERY`` requests to a ``query``
+    handler. :issue:`6065`
 
 
 Version 3.1.3

src/flask/sansio/scaffold.py

@@ -332,6 +332,17 @@ def patch(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
         """
         return self._method_route("PATCH", rule, options)
 
+    @setupmethod
+    def query(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
+        """Shortcut for :meth:`route` with ``methods=["QUERY"]``.
+
+        The ``QUERY`` method is a safe, idempotent request method that
+        carries content in the request body, defined in :rfc:`10008`.
+
+        .. versionadded:: 3.2
+        """
+        return self._method_route("QUERY", rule, options)
+
     @setupmethod
     def route(self, rule: str, **options: t.Any) -> t.Callable[[T_route], T_route]:
         """Decorate a view function to register it with the given URL

src/flask/views.py

@@ -9,7 +9,7 @@
 F = t.TypeVar("F", bound=t.Callable[..., t.Any])
 
 http_method_funcs = frozenset(
-    ["get", "post", "head", "options", "delete", "put", "trace", "patch"]
+    ["get", "post", "head", "options", "delete", "put", "trace", "patch", "query"]
 )
 
 

tests/test_basic.py

@@ -69,6 +69,19 @@ def test_method_route_no_methods(app):
         app.get("/", methods=["GET", "POST"])
 
 
+def test_query_method_route(app, client):
+    @app.query("/")
+    def query():
+        return flask.request.get_data(as_text=True)
+
+    rv = client.open("/", method="QUERY", data="select=*")
+    assert rv.status_code == 200
+    assert rv.data == b"select=*"
+    # The QUERY method is advertised like any other registered method.
+    rv = client.open("/", method="OPTIONS")
+    assert "QUERY" in rv.allow
+
+
 def test_provide_automatic_options_attr_disable(
     app: flask.Flask, client: FlaskClient
 ) -> None:

tests/test_views.py

@@ -39,6 +39,20 @@ def post(self):
     common_test(app)
 
 
+def test_query_method_view(app, client):
+    class Index(flask.views.MethodView):
+        def query(self):
+            return flask.request.get_data(as_text=True)
+
+    app.add_url_rule("/", view_func=Index.as_view("index"))
+
+    assert Index.methods == {"QUERY"}
+    rv = client.open("/", method="QUERY", data="select=*")
+    assert rv.status_code == 200
+    assert rv.data == b"select=*"
+    assert client.get("/").status_code == 405
+
+
 def test_view_patching(app):
     class Index(flask.views.MethodView):
         def get(self):