Properly handle nick assignment when joining a MUC room

[PaulSD]

When joining a MUC room, the MUC protocol allows the server ignore the nick requested by the client and assign a different nick. As currently implemented, Candy breaks if the server does this. This patch corrects this issue.

Thanks!

[mweibel]

Hey Paul,

thanks for your various contributions 👍 :)
Is there a possibility to test it? Didn't encounter this case yet and can't really see how to force this :D

Will release a new beta with this fix afterwards.

• Michael

[PaulSD]

I've tested it against my own XMPP server, which runs a customized version of MongooseIM (https://github.com/esl/MongooseIM). Our users authenticate to the server using an enterprise login account, and our MUC module requires the user's nick to be set to their real name (so it assigns the proper nick using their enterprise account info if the user doesn't specify the correct one when joining a room).

Unfortunately, I don't think any of the standard XMPP servers do something like this out-of-the-box, so testing it will probably require patching the server.

Here is a simple patch for ejabberd (https://github.com/processone/ejabberd) if you want to try it:

diff --git a/src/mod_muc_room.erl b/src/mod_muc_room.erl
index b1c5c92..2f19ae2 100644
--- a/src/mod_muc_room.erl
+++ b/src/mod_muc_room.erl
@@ -1762,10 +1762,11 @@ nick_collision(User, Nick, StateData) ->
       jlib:jid_remove_resource(jlib:jid_tolower(UserOfNick))
        /= jlib:jid_remove_resource(jlib:jid_tolower(User)).

-add_new_user(From, Nick,
+add_new_user(From, _RequestedNick,
             #xmlel{attrs = Attrs, children = Els} = Packet,
             StateData) ->
     Lang = xml:get_attr_s(<<"xml:lang">>, Attrs),
+    Nick = <<"Nick Assignment Test">>,
     MaxUsers = get_max_users(StateData),
     MaxAdminUsers = MaxUsers +
                      get_max_users_admin_threshold(StateData),
@@ -2178,6 +2179,10 @@ send_new_presence(NJID, Reason, StateData) ->
                                          [#xmlel{name = <<"status">>,
                                                  attrs =
                                                      [{<<"code">>, <<"110">>}],
+                                                 children = []},
+                                          #xmlel{name = <<"status">>,
+                                                 attrs =
+                                                     [{<<"code">>, <<"210">>}],
                                                  children = []}
                                           | Status2];
                                      false -> Status2

[mweibel]

Thanks for the patch. Somehow though I couldn't try it out because of some library missing.. Anyway, you have an interesting use case :)

I merged it in, as you see.