Add more control for decoding IQ payloads

src/ejabberd_local.erl

@@ -96,13 +96,7 @@ process_iq(From, To, #iq{type = T} = Packet) when T == get; T == set ->
     Err = xmpp:make_error(Packet, xmpp:err_bad_request()),
     ejabberd_router:route(To, From, Err);
 process_iq(From, To, #iq{type = T} = Packet) when T == result; T == error ->
-    try
-	NewPacket = xmpp:decode_els(Packet),
-	process_iq_reply(From, To, NewPacket)
-    catch _:{xmpp_codec, Why} ->
-	    ?DEBUG("failed to decode iq-result ~p: ~s",
-		   [Packet, xmpp:format_error(Why)])
-    end.
+    process_iq_reply(From, To, Packet).
 
 -spec process_iq_reply(jid(), jid(), iq()) -> any().
 process_iq_reply(From, To, #iq{id = ID} = IQ) ->

src/gen_iq_handler.erl

@@ -153,11 +153,9 @@ process_iq(_Host, Module, Function, From, To, IQ0) ->
 -spec process_iq(module(), atom(), iq()) -> ignore | iq().
 process_iq(Module, Function, #iq{lang = Lang, sub_els = [El]} = IQ) ->
     try
-	%% TODO: move this 'conditional' decoding somewhere
-	%% IQ handler should know *nothing* about vCards.
-	Pkt = case xmpp:get_ns(El) of
-		  ?NS_VCARD when Module == mod_vcard -> El;
-		  _ -> xmpp:decode(El)
+	Pkt = case erlang:function_exported(Module, decode_iq_subel, 1) of
+		  true -> Module:decode_iq_subel(El);
+		  false -> xmpp:decode(El)
 	      end,
 	Module:Function(IQ#iq{sub_els = [Pkt]})
     catch error:{xmpp_codec, Why} ->

src/mod_delegation.erl

@@ -18,7 +18,7 @@
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
 	 terminate/2, code_change/3]).
 -export([component_connected/1, component_disconnected/2,
-	 ejabberd_local/1, ejabberd_sm/1,
+	 ejabberd_local/1, ejabberd_sm/1, decode_iq_subel/1,
 	 disco_local_features/5, disco_sm_features/5,
 	 disco_local_identity/5, disco_sm_identity/5]).
 
@@ -56,6 +56,12 @@ mod_opt_type(_) ->
 depends(_, _) ->
     [].
 
+-spec decode_iq_subel(xmpp_element()) -> xmpp_element();
+		     (xmlel()) -> xmlel().
+%% Tell gen_iq_handler not to auto-decode IQ payload
+decode_iq_subel(El) ->
+    El.
+
 -spec component_connected(binary()) -> ok.
 component_connected(Host) ->
     lists:foreach(

src/mod_vcard.erl

@@ -37,7 +37,7 @@
 	 remove_user/2, export/1, import/1, import/3, depends/2,
 	 process_search/1, process_vcard/1, get_vcard/2,
 	 disco_items/5, disco_features/5, disco_identity/5,
-	 mod_opt_type/1, set_vcard/3, make_vcard_search/4]).
+	 decode_iq_subel/1, mod_opt_type/1, set_vcard/3, make_vcard_search/4]).
 
 -include("ejabberd.hrl").
 -include("logger.hrl").
@@ -167,6 +167,14 @@ get_sm_features(Acc, _From, _To, Node, _Lang) ->
       _ -> Acc
     end.
 
+-spec decode_iq_subel(xmpp_element() | xmlel()) -> xmpp_element() | xmlel().
+%% Tell gen_iq_handler not to decode vcard elements
+decode_iq_subel(El) ->
+    case xmpp:get_ns(El) of
+	?NS_VCARD -> xmpp:encode(El);
+	_ -> xmpp:decode(El)
+    end.
+
 -spec process_local_iq(iq()) -> iq().
 process_local_iq(#iq{type = set, lang = Lang} = IQ) ->
     Txt = <<"Value 'set' of 'type' attribute is not allowed">>,