Multi-user chat

With Multi-User Chat (short MUC , German multi-user chat ), and group chat are at XMPP , the chat rooms designated, where multiple users can converse simultaneously.

Similar to Internet Relay Chat ( IRC ), a chat room can have different statuses (visible, hidden, password-protected, etc.) and the participants take on the role of participant, visitor or moderator (similar to the IRC operator , voice, etc.).

However, the MUC has many advantages over the IRC. This is how you go online in the MUC with its globally unique Jabber Identifier , which cannot be used by someone else. This means that the MUC does not need any cumbersome services (such as NickServ ) to be able to clearly identify users. In addition, rooms (channels) can be registered in the MUC without detours via bots (such as ChanServ ). In addition, the different rights of users in a room (owner, operator, authorized to speak, authorized to read, banned) are linked to the Jabber identifier of the respective user, so that rooms are not "taken over" by others - as in IRC - or banned users after changing the host and the nickname can re-enter the room. In addition, the MUC has an optional feature to log calls on the server without a bot . In order to maintain anonymity, you can (optionally) choose any name in the MUC, which is then sent to normal participants instead of the Jabber identifier. However, owners and operators can see the Jabber Identifier, which is also necessary to change the rights of a user in the room. Nicknames are chosen room-by-room and do not apply across the network as with IRC.

development

MUC is the last of a series of XMPP protocols . The original group chat protocol, on which today's multi-user conferences in common rooms are based, was expanded to include administrative functions and was called Conference. This extension, which was not officially adopted, was revised and finally formulated in an XMPP Extension Protocol .

In order to ensure that new users have as few problems as possible in the chat, the ability to perform the functions and actions in XEP -0045: Multi-User Chat was created to use commands in IRC style (e.g. / msg, / kick, / join) implement them or provide them via the context menus of the clients.

Functions

MUC offers various functions. So it is possible for the server to create a log file for a room on request . Regardless of this, the latest messages are also saved and sent to new visitors with the correct times, so that they can see what is currently being talked about.

In addition, each user in a chat can have different privileges, so he can write or change the subject in a room depending on his privileges. In addition, the privileges can allow users to kick or ban other users . You can also set which user can see the other's Jabber identifiers . And if the rights are sufficient, these users can change the rights of the other users and thus, for example, revoke their right to speak.

In addition, the number of users in a chat can be limited. A chat also continues without the user being present and it can also be hidden or protected with a password. And should an internal chat be set up, it is also possible to specify which users can join and which cannot. In addition, a chat can be anonymous and thus hide the other's Jabber Identifiers.

The role and rights of a present

Everyone in a chat room has a role in it. The three possible roles are: visitor, participant and moderator. A participant has all the rights that a visitor has. The moderator also has all the rights that a visitor or participant has.

If you enter a chat room, you are automatically assigned a role. The role in a chat room only remains as long as you are in this chat room. If you leave a chat room, all changes to the role are discarded. (Exceptions to this rule result from membership, which is explained below.)

Visitors

The visitor status is the lowest level in a channel. So he can only do things that are important to him. So he can see what is being written in the room. He can also change his status (presence) or nickname . He can also write private messages to others in the room or send invitations to others and invite the recipients to join the channel. He can only write messages in the room (visible to all) if the room does not have the "moderated" status.

Attendees

A participant also has the right to send messages in a moderated room. He can also change the subject, provided this right is not restricted to the moderators.

Moderators

The moderator can also kick others out of a room, provided the other is not a moderator. He can also turn visitors into participants and participants into visitors. He also sees the Jabber Identifier of all those present, even if the room has the status anonymous.

The affiliation of a person

In addition, everyone has an affiliation relating to the room. In contrast to the role, the affiliation is retained when someone leaves a chat room. If he enters a room again, he has the same affiliation as before.

The following affiliations exist: excluded (outcast), no (special) affiliation (no affiliation), member (member), administrator (admin) and owner (owner). As with the roles, all higher-ranking memberships also have all the rights of the weaker memberships.

Excluded

An excluded person does not have the right to enter the chat room (he has been banned ).

No affiliation

A person with no (special) affiliation can enter a room (unless this room is configured as "members only").

Members

A member can also enter rooms that are configured "only for members" and receive at least the role of participant in the moderated room and are therefore authorized to send messages to the chat room from the start.

Administrators

An administrator can also change affiliation with other members. In addition, every person invited by the administrator is assigned membership as a member in a “members only” configured room. The invitation must be made in accordance with the MUC protocol. An invitation according to the old protocol does not have this effect. In addition, the administrator can make others, except administrators or owners, excluded, i.e. refer them to the room (see the heading excluded ). In addition, he always has the role of moderator and can assign or remove the role of moderator to others.

owner

An owner is the highest belonging. As soon as a new room is created, the person who created the room is usually the owner immediately. He can change the configuration of the chat room and assign or remove the membership of an administrator or an owner. He can also dissolve the room again.

software

Client

Not every XMPP client supports all of the functions listed above. Here is a list of clients that (almost) fully support MUC:

• Coccinella (Windows / Linux / MAC OS X)
• Gajim (Windows / Linux)
• Psi (Windows / Linux / MAC OS X)
• Pidgin (Windows / Linux / MAC OS X) ( FAQ )
• Conversations (Android)

server

• ejabberd (erlang / GPL)
• prosody (lua / MIT license)
• Openfire Server (Java / Apache License 2.0)
• PSYCED (also PSYC and IRC capable)

List of known MUCs

Chat room	theme	language	Web link
[e-mail]	Ubuntu		http://www.ubuntuusers.de/
[e-mail]	Official MUC from Thereforefrei.org		http://www.deshalbfrei.org/
[e-mail]	General information from and about XMPP		http://web.jabber.ccc.de/
[e-mail]	eCS / OS / 2
[e-mail]	Assistance to Gajim		http://www.gajim.org/
[e-mail]	Help with conversations		https://conversations.im/
[e-mail]	Help from and for beginners		http://www.jabber.org/
[e-mail]	Help from and for users about IT and programming		http://www.uhuc.de/
[e-mail]	Official MUC for the Python MUC Bot SleekBot		http://code.google.com/p/sleekbot/
[e-mail]	Help on the Python programming language		http://www.python.de/
[e-mail]	Chat and help on the subject of "free messengers"		https://www.frei-messenger.de/
[e-mail]	IT security, data protection, hacking - MUC to Mike Kuketz's blog		https://www.kuketz-blog.de/

Web links

• Search engine for MUC rooms (PHP)
• Search engine for MUC rooms ( Gopher )
• debianforum.de - Introduction to JabberChat

swell

1. ↑ ^{a b} XMPP Standards Foundation: XEP-0045: Multi-User Chat Version 1.20, September 8, 2005