From d46b7d59084f256c0ecd573a157e43bbc3655689 Mon Sep 17 00:00:00 2001
From: Christophe Romain <christophe.romain@process-one.net>
Date: Mon, 14 Apr 2008 12:02:18 +0000
Subject: [PATCH] Cache negative response (EJAB-474)

SVN Revision: 1294
---
 ChangeLog        |  4 ++++
 src/mod_caps.erl | 17 +++++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 7dc1aab06..282506e0f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2008-04-14  Christophe Romain <christophe.romain@process-one.net>
+
+	* src/mod_caps.erl: Cache negative response (EJAB-474)
+
 2008-04-12  Badlop  <badlop@process-one.net>
 
 	* src/web/ejabberd_web_admin.erl: Include Last-Modified HTTP
diff --git a/src/mod_caps.erl b/src/mod_caps.erl
index 8bf37d8be..dee9078a9 100644
--- a/src/mod_caps.erl
+++ b/src/mod_caps.erl
@@ -250,8 +250,21 @@ handle_cast({disco_response, From, _To,
 		    ?ERROR_MSG("ID '~s' matches no query", [ID])
 	    end;
 	{error, _} ->
-	    gen_server:cast(self(), visit_feature_queries),
-	    ?DEBUG("Error IQ reponse from ~s:~n~p", [jlib:jid_to_string(From), SubEls]);
+	    %% XXX: if we get error, we cache empty feature not to probe the client continuously
+	    case ?DICT:find(ID, Requests) of
+		{ok, {Node, SubNode}} ->
+		    Features = [],
+		    mnesia:transaction(
+		      fun() ->
+			      mnesia:write(#caps_features{node_pair = {Node, SubNode},
+							  features = Features})
+		      end),
+		    gen_server:cast(self(), visit_feature_queries);
+		error ->
+		    ?ERROR_MSG("ID '~s' matches no query", [ID])
+	    end;
+	    %gen_server:cast(self(), visit_feature_queries),
+	    %?DEBUG("Error IQ reponse from ~s:~n~p", [jlib:jid_to_string(From), SubEls]);
 	{result, _} ->
 	    ?DEBUG("Invalid IQ contents from ~s:~n~p", [jlib:jid_to_string(From), SubEls]);
 	_ ->