XEP-0198: Support "resend_on_timeout: if_offline"

If "resend_on_timeout" is set to "if_offline", resend unacknowledged
stanzas only if no other resource is online when the session times out.
In other words, allow for sending them to offline storage, but nowhere
else.

diff --git a/doc/guide.tex b/doc/guide.tex
index 27fcfc18128bfaef0df7c2329d2b07bdabba169e..efebc2521708f677359ee94b44cb54d9841852d0 100644 (file)
--- a/doc/guide.tex
+++ b/doc/guide.tex
@@ -1022,7 +1022,7 @@ request_handlers:
   /"a"/"b": mod_foo
   /"http-bind": mod_http_bind
 \end{verbatim}
-  \titem{resend\_on\_timeout: true|false}
+  \titem{resend\_on\_timeout: true|false|if\_offline}
     If \term{stream\_management} is enabled and this option is set to
     \term{true}, any stanzas that weren't acknowledged by the client
     will be resent on session timeout. This behavior might often be
@@ -1030,8 +1030,12 @@ request_handlers:
     circumstances. For example, a message that was sent to two resources
     might get resent to one of them if the other one timed out.
     Therefore, the default value for this option is \term{false}, which
-    tells ejabberd to generate an error message instead. The option can
-    be specified for \term{ejabberd\_c2s} listeners.
+    tells ejabberd to generate an error message instead. As an
+    alternative, the option may be set to \term{if\_offline}. In this
+    case, unacknowledged stanzas are resent only if no other resource is
+    online when the session times out. Otherwise, error messages are
+    generated. The option can be specified for \term{ejabberd\_c2s}
+    listeners.
   \titem{resume\_timeout: Seconds}
     This option configures the number of seconds until a session times
     out if the connection is lost. During this period of time, a client

diff --git a/src/ejabberd_c2s.erl b/src/ejabberd_c2s.erl
index cb6f9e6d83059f024c9be56939458da83b467dd1..d0dfd25530ba68473bca5cfa898f69a331a76521 100644 (file)
--- a/src/ejabberd_c2s.erl
+++ b/src/ejabberd_c2s.erl
@@ -316,7 +316,11 @@ init([{SockMod, Socket}, Opts]) ->
                      Timeout when is_integer(Timeout), Timeout >= 0 -> Timeout;
                      _ -> 300
                    end,
-    ResendOnTimeout = proplists:get_bool(resend_on_timeout, Opts),
+    ResendOnTimeout = case proplists:get_value(resend_on_timeout, Opts) of
+                       Resend when is_boolean(Resend) -> Resend;
+                       if_offline -> if_offline;
+                       _ -> false
+                     end,
     IP = peerip(SockMod, Socket),
     Socket1 = if TLSEnabled andalso
                 SockMod /= ejabberd_frontend_socket ->
@@ -2879,7 +2883,15 @@ handle_unacked_stanzas(_StateData, _F) ->
 handle_unacked_stanzas(StateData)
     when StateData#state.mgmt_state == active;
         StateData#state.mgmt_state == pending ->
-    ReRoute = case StateData#state.mgmt_resend of
+    ResendOnTimeout =
+       case StateData#state.mgmt_resend of
+         Resend when is_boolean(Resend) ->
+             Resend;
+         if_offline ->
+             ejabberd_sm:get_user_resources(StateData#state.user,
+                                            StateData#state.server) == []
+       end,
+    ReRoute = case ResendOnTimeout of
                true ->
                    fun ejabberd_router:route/3;
                false ->