feat(status_codes) Handle 451 Unavailable For Legal Reasons

See https://en.wikipedia.org/wiki/HTTP_451 for details.

doc/api/errors.rst

@@ -37,4 +37,5 @@ Predefined Errors
         HTTPMethodNotAllowed, HTTPNotAcceptable, HTTPConflict,
         HTTPLengthRequired, HTTPPreconditionFailed, HTTPUnsupportedMediaType,
         HTTPRangeNotSatisfiable, HTTPUnprocessableEntity, HTTPTooManyRequests,
-        HTTPInternalServerError, HTTPBadGateway, HTTPServiceUnavailable
+        HTTPUnavailableForLegalReasons, HTTPInternalServerError,
+        HTTPBadGateway, HTTPServiceUnavailable

doc/api/status.rst

@@ -100,6 +100,7 @@ string objects that must be created when preparing responses.
     HTTP_PRECONDITION_REQUIRED = HTTP_428
     HTTP_TOO_MANY_REQUESTS = HTTP_429
     HTTP_REQUEST_HEADER_FIELDS_TOO_LARGE = HTTP_431
+    HTTP_UNAVAILABLE_FOR_LEGAL_REASONS = HTTP_451
 
     HTTP_400 = '400 Bad Request'
     HTTP_401 = '401 Unauthorized'  # <-- Really means "unauthenticated"
@@ -125,6 +126,7 @@ string objects that must be created when preparing responses.
     HTTP_428 = '428 Precondition Required'
     HTTP_429 = '429 Too Many Requests'
     HTTP_431 = '431 Request Header Fields Too Large'
+    HTTP_451 = '451 Unavailable For Legal Reasons'
 
 5xx Server Error
 ----------------

falcon/errors.py

@@ -361,6 +361,26 @@ class HTTPTooManyRequests(HTTPError):
                                                   **kwargs)
 
 
+class HTTPUnavailableForLegalReasons(OptionalRepresentation, HTTPError):
+    """451 Unavailable For Legal Reasons.
+
+    This status code indicates that the server is denying access to the
+    resource as a consequence of a legal demand.
+
+    See also:
+    https://datatracker.ietf.org/doc/draft-ietf-httpbis-legally-restricted-status/
+
+    Args:
+        title (str): Error title (e.g., 'Legal reason: <reason>').
+        kwargs (optional): Same as for ``HTTPError``.
+
+    """
+
+    def __init__(self, title, **kwargs):
+        super(HTTPUnavailableForLegalReasons, self).__init__(status.HTTP_451,
+                                                             title, **kwargs)
+
+
 class HTTPInternalServerError(HTTPError):
     """500 Internal Server Error.
 

falcon/status_codes.py

@@ -100,6 +100,8 @@ HTTP_429 = '429 Too Many Requests'
 HTTP_TOO_MANY_REQUESTS = HTTP_429
 HTTP_431 = '431 Request Header Fields Too Large'
 HTTP_REQUEST_HEADER_FIELDS_TOO_LARGE = HTTP_431
+HTTP_451 = '451 Unavailable For Legal Reasons'
+HTTP_UNAVAILABLE_FOR_LEGAL_REASONS = HTTP_451
 
 HTTP_500 = '500 Internal Server Error'
 HTTP_INTERNAL_SERVER_ERROR = HTTP_500

tests/test_httperror.py

@@ -773,5 +773,7 @@ class TestHTTPError(testing.TestBase):
         self._misc_test(falcon.HTTPUnsupportedMediaType, falcon.HTTP_415,
                         needs_title=False)
         self._misc_test(falcon.HTTPUnprocessableEntity, falcon.HTTP_422)
+        self._misc_test(falcon.HTTPUnavailableForLegalReasons, falcon.HTTP_451,
+                        needs_title=False)
         self._misc_test(falcon.HTTPInternalServerError, falcon.HTTP_500)
         self._misc_test(falcon.HTTPBadGateway, falcon.HTTP_502)