Do not strip entity-headers with HTTP status 304 or 412

sanic/helpers.py

@@ -122,25 +122,6 @@ def is_hop_by_hop_header(header):
     return header.lower() in _HOP_BY_HOP_HEADERS
 
 
-def remove_entity_headers(headers, allowed=("content-location", "expires")):
-    """
-    Removes all the entity headers present in the headers given.
-    According to RFC 2616 Section 10.3.5,
-    Content-Location and Expires are allowed as for the
-    "strong cache validator".
-    https://tools.ietf.org/html/rfc2616#section-10.3.5
-
-    returns the headers without the entity headers
-    """
-    allowed = set([h.lower() for h in allowed])
-    headers = {
-        header: value
-        for header, value in headers.items()
-        if not is_entity_header(header) or header.lower() in allowed
-    }
-    return headers
-
-
 def import_string(module_name, package=None):
     """
     import a module or class by string path.

sanic/response/types.py

@@ -24,7 +24,6 @@
     Default,
     _default,
     has_message_body,
-    remove_entity_headers,
 )
 from sanic.http import Http
 
@@ -106,9 +105,6 @@ def processed_headers(self) -> Iterator[Tuple[bytes, bytes]]:
         Returns:
             Iterator[Tuple[bytes, bytes]]: A list of header tuples encoded in bytes for sending
         """  # noqa: E501
-        # TODO: Make a blacklist set of header names and then filter with that
-        if self.status in (304, 412):  # Not Modified, Precondition Failed
-            self.headers = remove_entity_headers(self.headers)
         if has_message_body(self.status):
             self.headers.setdefault("content-type", self.content_type)
         # Encode headers into bytes

tests/test_response.py

@@ -178,6 +178,10 @@ async def no_content_unmodified_handler(request: Request):
     async def unmodified_handler(request: Request):
         return json(JSON_DATA, status=304)
 
+    @app.get("/precondition")
+    async def precondition_handler(request: Request):
+        return json(JSON_DATA, status=412)
+
     @app.delete("/")
     async def delete_handler(request: Request):
         return json(None, status=204)
@@ -193,6 +197,10 @@ def test_json_response(json_app):
     assert response.text == json_dumps(JSON_DATA)
     assert response.json == JSON_DATA
 
+    request, response = json_app.test_client.get("/precondition")
+    assert response.status == 412
+    assert response.json == JSON_DATA
+
 
 def test_no_content(json_app):
     request, response = json_app.test_client.get("/no-content")