[Standards] Group chat protocol

Ненахов Андрей andrew.nenakhov at redsolution.ru
Sun Jun 3 14:30:48 UTC 2018

To whom it may concern, we're working on group chat solution for XMPP.

It is quite a simple solution that we feel is good enough to counter most
issues of XEP-0045.

It is quite simple:

   - Group chat is listed in a roster, we use standard xmpp subscription to
   join-leave group chats
   - Clients can differentiate group chat contacts from regular contacts in
   their rosters by a specially formatted presence.
   - Sending messages to group chat is done by sending messages to group
   chat JID
   - Group chat server resends messages to everyone but sender with special
   formatting, that includes unique message ID, sender nickname, sender JID,
   avatar hash. For older clients, we provide a plaintext body that starts
   with *nickname:\n *before actual message.
   This way allows a client to display everything they need without
   fetching data from a list of group chat members. Avatar hash is also a
   filename so avatar can be retrieved from a server when needed.
   - Non-anonymous groups transmit real user JID, semi-anonymous transmit
   JID assigned to this user for identification purposes.
   - Nicknames and avatars are retrieved from user's vCard when he joins
   the group. Can be redefined later by user
   - No private messages support. XMPP is already a protocol for private
   messaging. In non-anonymous groups users can contact each other directly.
   In semi-anonymous groups, users can send a special message (via group) to
   other users that would disclose their real JID to the user they want to
   talk to. If the recipient accepts he can add him to his personal roster and
   chat privately.
   - Clients can fetch a list of group chat members and turn on/off
   receiving updates. We imagine users of big groups of 300+ users don't
   really want to receive presence data all the time, but might want to open a
   list of participants and see who's online.

Group chat also provides a centralized message archive, so members can
fetch chat history directly from group chat server.

Advantages of this approach:

   - Simple
   - Compatible with existing clients
   - Compatible with existing servers
   - Easy to implement in any XMPP client

Parts of it are already implemented (we run it on modified ejabberd), we
already use it for internal communications. It is also already supported in
a web version of Xabber. I expect a mid-July release with support in Web,
Android and iOS versions of Xabber. Most likely we'll also make a Gajim
plugin, but a bit later and maybe not fully featured.

Admin stuff is not yet done. Most likely will be somewhat akin to Telegram
group chats model. Admins can be granted rights by owners and other admins,
users can be restricted by admins.

Anyone interested to try it can connect with me
xmpp:andrew.nenakhov at redsolution.com, I'll invite you to
existing groupchat we made. Best way to try is to connect using development
version of Xabber, https://web.xabber.com/develop/
For now, it's limited (and sometimes breaks ;) ) and you can only join
already created group chats, I think we'll also add permissions for anyone
to create group chats on our server.


Documentation for all of this is now in a somewhat inconsistent state (and
is also in Russian), we changed a number of things from our original plan
and our proto-protocol spec is now already outdated at some places, I plan
to fix it next week and translate to English.

*Important notice.* I fully understand that it is almost inevitable that
we'll now receive a very big share of criticism from people who won't like
this and that and how we do everything *wrong*. We will release support for
this protocol in our clients and server no matter what because we need it
for our product and we can't wait until this MIX enormity somehow settles
down. Thus said, we're very open to constructive feedback, and since this
functionality is in very active development we might consider changing some

Ненахов Андрей
Директор ООО "Редсолюшн" (Челябинск)
(351) 750-50-04
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