anchor.diff:      send_json(Req, Code, [], Value).
   
   send_json(Req, Code, Headers, Value) ->
  -    ContentType = negotiate_content_type(Req),
  +    DefaultHeaders = [
  +        {"Content-Type", negotiate_content_type(Req)},
  +        {"Cache-Control", "must-revalidate"}
  +    ] ++ server_header(),
       Body = cjson:encode(Value),
  -    Resp = Req:respond({Code, [{"Content-Type", ContentType}] ++ Headers,
  -                        Body}),
  +    Resp = Req:respond({Code, DefaultHeaders ++ Headers, Body}),
       {ok, Resp}.
   
   start_json_response(Req, Code) ->
       start_json_response(Req, Code, []).
   
   start_json_response(Req, Code, Headers) ->
  -    ContentType = negotiate_content_type(Req),
  -    Req:respond({Code, [{"Content-Type", ContentType}] ++ Headers, chunked}).
  +    DefaultHeaders = [
  +        {"Content-Type", negotiate_content_type(Req)},
  +        {"Cache-Control", "must-revalidate"}
  +    ] ++ server_header(),
  +    Req:respond({Code, DefaultHeaders ++ Headers, chunked}).
   
   end_json_response(Resp) ->
       Resp:write_chunk(""),
  
positive.code:             throw({not_found, missing});
          {Type, Bin} ->
              Resp = Req:respond({200, [
                  {"content-type", Type},
                  {"content-length", integer_to_list(couch_doc:bin_size(Bin))}
              ], chunked}),
              couch_doc:bin_foldl(Bin,
                  fun(BinSegment, []) ->
                      ok = Resp:write_chunk(BinSegment),
  
negative.code:     {500, error, Error}.
  
  send_error(Req, {method_not_allowed, Methods}) ->
      {ok, Req:respond({405, [{"Allow", Methods}] ++ server_header(), <<>>})};
  send_error(Req, {modified, Etag}) ->
      {ok, Req:respond({412, [{"Etag", Etag}] ++ server_header(), <<>>})};
  send_error(Req, {not_modified, Etag}) ->
      {ok, Req:respond({304, [{"Etag", Etag}] ++ server_header(), <<>>})};
  send_error(Req, Error) ->
      {Code, Json} = error_to_json(Error),
      ?LOG_INFO("HTTP Error (code ~w): ~p", [Code, Error]),
  