Adding 421 Misdirected Request HTTP Exception

CHANGES.rst

@@ -9,6 +9,7 @@ Unreleased
 -   ``CacheControl.no_transform`` is a boolean when present. ``min_fresh`` is
     ``None`` when not present. Added the ``must_understand`` attribute. Fixed
     some typing issues on cache control. :issue:`2881`
+-   Add 421 ``MisdirectedRequest`` HTTP exception. :issue:`2850`
 
 
 Version 3.0.6

docs/exceptions.rst

@@ -44,6 +44,8 @@ The following error classes exist in Werkzeug:
 
 .. autoexception:: ImATeapot
 
+.. autoexception:: MisdirectedRequest
+
 .. autoexception:: UnprocessableEntity
 
 .. autoexception:: Locked

src/werkzeug/exceptions.py

@@ -571,6 +571,17 @@ class ImATeapot(HTTPException):
     description = "This server is a teapot, not a coffee machine"
 
 
+class MisdirectedRequest(HTTPException):
+    """421 Misdirected Request
+
+    Indicates that the request was directed to a server that is not able to
+    produce a response.
+    """
+
+    code = 421
+    description = "The server is not able to produce a response."
+
+
 class UnprocessableEntity(HTTPException):
     """*422* `Unprocessable Entity`
 

tests/test_exceptions.py

@@ -37,6 +37,7 @@ def test_proxy_exception():
         (exceptions.RequestEntityTooLarge, 413),
         (exceptions.RequestURITooLarge, 414),
         (exceptions.UnsupportedMediaType, 415),
+        (exceptions.MisdirectedRequest, 421),
         (exceptions.UnprocessableEntity, 422),
         (exceptions.Locked, 423),
         (exceptions.InternalServerError, 500),