util.stanza: Support the 'by' attribute on errors

This is to be used when the entity generating the error is not the same
as the one the stanza was directed to, e.g. an intermediate server.

1 files changed, 5 insertions, 2 deletions

diff --git a/util/stanza.lua b/util/stanza.lua
index 8ff1aae3..8e46f90f 100644
--- a/util/stanza.lua
+++ b/util/stanza.lua
@@ -447,7 +447,7 @@ local function reply(orig)
 end
 
 local xmpp_stanzas_attr = { xmlns = xmlns_stanzas };
-local function error_reply(orig, error_type, condition, error_message)
+local function error_reply(orig, error_type, condition, error_message, error_by)
 	if not is_stanza(orig) then
 		error("bad argument to error_reply: expected stanza, got "..type(orig));
 	elseif orig.attr.type == "error" then
@@ -455,7 +455,10 @@ local function error_reply(orig, error_type, condition, error_message)
 	end
 	local t = reply(orig);
 	t.attr.type = "error";
-	t:tag("error", {type = error_type}) --COMPAT: Some day xmlns:stanzas goes here
+	if t.attr.from == error_by then
+		error_by = nil;
+	end
+	t:tag("error", {type = error_type, by = error_by}) --COMPAT: Some day xmlns:stanzas goes here
 	:tag(condition, xmpp_stanzas_attr):up();
 	if error_message then t:text_tag("text", error_message, xmpp_stanzas_attr); end
 	return t; -- stanza ready for adding app-specific errors