jabber.el manual
****************

This manual is for jabber.el, version 0.8.

Copyright © 2004, 2005, 2006, 2007, 2008 Magnus Henoch, Tom Berger.

     Permission is granted to make and distribute verbatim copies or modified versions of this manual, provided the copyright notice and this permission notice are preserved on all copies.

Introduction
************

jabber.el is a Jabber client running under Emacs.  For more information on the open-protocol instant messaging network Jabber, please visit http://www.jabber.org.

As a Jabber client, jabber.el is mostly just a face in the crowd, except that it uses buffers where GUI clients have windows.  There is a roster buffer, and to chat with someone you open a chat buffer, and there are buffers for interaction with servers and services.  Then again, jabber.el delivers excellent console performance and customizable hooks (if you have speech synthesizer software, hook it up to your presence alerts).

jabber.el does not yet support PGP encryption, sending and receiving roster items, and various other things.

Contact
=======

  * There is a web page at http://emacs-jabber.sf.net/.

  * There is a Sourceforge project page at http://sourceforge.net/projects/emacs-jabber, with bug and patch trackers.

  * There is a mailing list: emacs-jabber-general@lists.sourceforge.net, https://lists.sourceforge.net/lists/listinfo/emacs-jabber-general, http://dir.gmane.org/gmane.emacs.jabber.general

  * There is a chat room, jabber.el@conference.jabber.se.  If you have successfully connected, you can join it by typing M-x jabber-groupchat-join and entering the address.

Basic operation
***************

This chapter is intended as an introduction to basic usage of jabber.el.  If you have used Jabber before and are familiar with the terminology, you might find it a bit too basic---in that case, just skim it, making sure to pick up the commands mentioned.

I'll assume that you have already successfully installed jabber.el; if not, consult the README file.  Also, make sure you have (require 'jabber) or (load "jabber-autoloads") in your .emacs.

There are a handful of global keybindings for common commands.  They start with C-x C-j, and you can get a list of them by typing C-x C-j C-h.

Do you have a Jabber account?
=============================

Jabber has become rather popular as an instant messaging technology. Several sites use it, but often not under the names ``Jabber'' or ``XMPP''.  Examples:

  * Google Talk uses Jabber.  If you have a Gmail address, you can use it as a Jabber ID.  See Account settings, for Google-specific configuration.

  * LJ Talk (of Livejournal) uses Jabber.  Your Jabber ID is LJUSERNAME@livejournal.com.

Registering an account
======================

If you do not yet have a Jabber account, you can register one.  The registration processes for various servers differ, but many servers support so-called ``in-band registration'', which is described in this section.

To register an account, type C-u M-x jabber-connect and enter your desired JID in the form USERNAME@SERVER.  You will be presented with a registration form to fill out and send.  There the username you chose will be prefilled.  After registration, you can connect to the server as usual.

Connecting
==========

Now, type C-x C-j C-c and enter your JID and password.  If you successfully connect, jabber.el will download your roster and display it in a buffer called *-jabber-*.

By default, you will appear as ``online'' to your contacts.  To change this to e.g. ``away'', type M-x jabber-send-presence or C-x C-j C-p.  See Presence, for more information.

To disconnect, type M-x jabber-disconnect or C-x C-j C-d. Use M-x jabber-disconnect-one to disconnect just one account (or just type C-u C-x C-j C-d).

If you don't want to type your JID every time you connect, you can save it in the variable jabber-account-list.  See Account settings.  If you configure more than one account, all of them will be connected when you type C-x C-j C-c, as that key is bound to jabber-connect-all.  To connect only one account, possibly one that's not in your list, type M-x jabber-connect or C-u C-x C-j C-c.

Chatting
========

There are several ways to open a chat buffer.  The shortest way is to put point over the person you want to chat with in the roster display and hit RET.

You can also use the function jabber-chat-with.  This function is bound to C-x C-j C-j in the global keymap.  You will be asked to enter a JID in the minibuffer.  You can also enter the roster name of one of your contacts.  All JIDs and names in your roster can be tab-completed.

You can also use menus to access commands.  In the roster display, you can access several menus through keystrokes or mouse clicks.  You can bring one big menu up by pressing the second mouse button, or you can bring up the ``chat menu'' by typing C-c C-c.  If you do the latter while point is on a roster entry, that entry will be the default value when you are asked for whom to chat with.

Now, try opening a chat with someone.  A buffer named *-jabber-chat-:-PERSON-* will be created and selected. Type your message at the end of the buffer, and hit RET to send it.  To include a newline in your message, use C-j.

When you receive a message from someone, you will see a red indicator in the mode line.  You can click this indicator with the mouse, or type C-x C-j C-l to switch to the relevant buffer.  See Tracking activity.

Presence
========

Presence is the Jabber term for letting other people know that you are online, and additionally how ``available'' you are.  There are three elements to presence: availability state (called ``show''), status message, and priority.

Your show state may either be empty (meaning simply ``online''), or one of away, xa, dnd and chat, meaning ``away'', ``extended away'' (i.e. away for an extended period), ``do not disturb'', and ``free for chat'', respectively.  This information is available to everyone subscribing to your presence, but technically it does not restrict anyone's actions.  You can chat with people even if you claim to be away.

The status message is a short text complementing your show status, such as ``at home'', ``working'', ``phone'', ``playing games'' or whatever you want.  It is sent to everyone subscribing to your presence, but not all clients prominently display it to the user.

The priority is only interesting if you are running more than one Jabber client at a time accessing the same account.  See Resources and priority.

To set your presence, use the function jabber-send-presence (bound to C-x C-j C-p). It can be called both interactively and in Lisp code.  For the latter case, use something like (jabber-send-presence "away" "idle for 10 minutes" 10).  There are a few shortcuts:

C-x C-j C-a
     Send ``away'' presence (with prefix argument, specify status text)

C-x C-j C-x
     Send ``extended away'' presence (with prefix argument, specify status text)

C-x C-j C-o
     Send default presence (see below)

By default, jabber.el sets your presence when you connect.  If you want it not to do that, remove jabber-send-current-presence from jabber-post-connect-hooks.  If you want to change the presence that is sent, change the variables jabber-default-show, jabber-default-status and jabber-default-priority.

With jabber.el, you can set your presence remotely.  See Ad-Hoc Commands.

Resources and priority
----------------------

Every connection to an account has a specific name, a resource. The account itself has a JID of the form USERNAME@SERVER (a bare JID), but the connections have JIDs of the form USERNAME@SERVER/RESOURCE (a full JID). You can choose the resource name yourself by entering a JID of the latter form at the connection prompt (see Connecting), or by configuring it in jabber-account-list (see Account settings)

Each session has a priority.  The priority determines what happens when a message is sent to the bare JID (i.e. without specifying what connection should receive message).  Such messages are delivered to the connection with the highest non-negative priority value.  If there are no connections, or if all connections have negative priority, the message is either stored on the server for later delivery or bounced to the sender, depending on the server configuration.

If there are several connections with the same priority, the behaviour depends on the server.  Some server implementations deliver the message to all such connections, while others choose one connection depending on certain rules.

Note that these rules do not apply when a message is sent to a full JID.  Such messages are sent to the specified resource, if it is still connected, and otherwise treated as messages to the bare JID.  In the chat buffers of jabber.el, messages are sent to whatever JID the last message came from (usually a full JID), or to the bare JID if no message has been received yet.  Other clients may have different behaviour.

Directed presence
-----------------

You can send ``directed presence'' with M-x jabber-send-directed-presence.  This is mostly useful to manage transports---sending directed presence is a way to turn them on and off.  You can also send directed presence to an annoying contact to appear as away or offline to that contact.  Note, however, that in both of these cases, all subscribed entities will get your next global presence update.

Presence subscription
=====================

Having permission to view the presence status of a person is called subscribing to his presence.  Presence subscription between two persons can be asymmetric.  Subscription state is shown in the roster display by arrows (see Customizing the roster buffer).  A left-pointing arrow means that the contact can see your presence (``from'').  A right-pointing arrow means that you can see the contact's presence (``to'').  The most common case is mutual subscription, a double-ended arrow (``both'').

When jabber.el receives a presence subscription request, it will present it to you in a chat buffer, and offer you to choose subscription mode and send a subscription request back to that person.  The ``Mutual'' button accepts the request and sends a reciprocal request. (If this request is superfluous, the server will drop it without bothering the contact.)  The ``One-way'' button accepts the request, but doesn't ask for a subscription in return.  The ``Decline'' button declines the request.

To request subscription to someone, type M-x jabber-send-subscription-request.  You will be prompted for the JID to send it to.  This command can also be accessed through the Roster menu, by typing C-c C-r in the roster buffer.  After that, you will probably want to give the contact a more readable name.  The command for that is jabber-roster-change, which is also available in the Roster menu or by typing e on a person in the roster buffer.

The roster buffer
=================

The roster buffer is called *-jabber-*.  It simply contains a list of the contacts on your roster.  If you have several accounts connected, contacts will be grouped by account.

In the roster buffer, any command which requires a JID will default to the JID under point when called.  These commands can be called through either keyboard menus or mouse menus.  To open a menu with the mouse, simply press the second mouse button over the JID in question. (For some reason, mouse menus don't work in XEmacs. Patches are welcome.)  This will bring up a menu with all available actions.  The keyboard menus are split into categories: Chat, Roster, Information, MUC (Multi-User Chat, or groupchat) and Services, opened by C-c C-c, C-c C-r, C-c C-i, C-c C-m and C-c C-s, respectively.

A list of keybindings is displayed at the top of the roster buffer. You can turn it off by setting jabber-roster-show-bindings to nil.

You can call jabber-display-roster (bound to g) to redisplay your roster according to changed preferences (see Customizing the roster buffer).  This will not refetch your roster from the server.  Refetching the roster is usually not needed, since updates are pushed to clients automatically.

You can choose not to have the roster updated automatically on presence changes (see Presence alerts).  In that case, you need to call jabber-display-roster manually.

Please note, that by default offline contacts showed in roster as any others. To hide them, you can use o in roster buffer. To permanently hide them, customize jabber-show-offline-contacts variable.

Groupchat
*********

The groupchat menu can be accessed by typing C-c C-m in the roster buffer.  You can also type the commands directly, as will be shown here.

To join a groupchat, type M-x jabber-groupchat-join.  You will be prompted for the groupchat to join, and your nickname in the groupchat.  This nickname doesn't need to have any correlation to your JID; in fact, groupchats are usually (but not always) configured such that only moderators can see your JID.  You can change your nickname with M-x jabber-muc-nick.  See Configuration, for setting default nicknames.

When trying to join a room, jabber.el first sends a service discovery info request to the room, to find out whether it exists and what features are enabled (in particular whether the room is password-protected).  However, this can cause problems with some buggy MUC services (or services that respond in a way that jabber.el doesn't expect).  A workaround for that is to set jabber-muc-disable-disco-check to t; however, the bug should be unearthed and fixed.

Groupchat messages will be displayed in a buffer called *-jabber-groupchat-:-GROUPCHAT-*.  By default, the buffer name is based on the JID of the chat room.  If you want a shorter name, you can add the chat room to your roster and give it a name, using the command M-x jabber-roster-change.  The groupchat buffer works much like the chat buffer.  It has its own class of alerts (see Customizing alerts), and uses activity tracking (see Tracking activity).

Also, to save from repeating unnesesary typing you can press Tab key to complete nick of a groupchat member that you are talking with. You can customize your form of personal talking in MUC (jabber-muc-completion-delimiter) and form of personal talking to you (jabber-muc-looks-personaling-symbols)---see ``jabber-chat'' customization group. Defaults are sane, so it is unlikely that you would want to change this, but... it is Emacs!

To change the topic of a groupchat, type M-x jabber-muc-set-topic. The current topic is shown in the header line.

To leave a groupchat, type M-x jabber-groupchat-leave.

If you are the owner of a groupchat, you can change its configuration by typing M-x jabber-groupchat-get-config.  A configuration form will be rendered in new buffer.

To see which people are in a groupchat, type M-x jabber-muc-names.  This gives a list of nicknames, ``roles'', ``affiliations'', and possibly JIDs.  See MUC Administration, for the meaning of roles and affiliations.

Configuration
=============

You can configure jabber.el to use a certain nickname for a certain room, or to automatically join a certain room when you connect.  You can do this either by storing bookmarks on the server or by setting Emacs variables.

Type M-x jabber-edit-bookmarks to add bookmarks.  You can specify the JID of the conference, the name of the conference (not used by jabber.el), whether to automatically join the room, your desired nickname (or leave empty), and the room password (or leave empty).

The default nickname for groupchats is the username part of your JID. If you don't use bookmarks, you can set different nicknames for different groups by customizing jabber-muc-default-nicknames. There you specify the JID of the group, and your preferred nickname.

Automatically joining certain rooms when connecting can be accomplished by setting jabber-muc-autojoin to a list containing the JIDs of the rooms you want to enter.  To disable this feature, remove jabber-muc-autojoin from jabber-post-connect-hooks.

Please note, that jabber-muc-default-nicknames and jabber-muc-autojoin are machine-local, but apply to all accounts---if you connect several accounts, both will try to connect to the same chat rooms, or use the same nickname.  This will lead to confusion.

Invitations
===========

You can invite someone to a groupchat with M-x jabber-muc-invite (also available in the MUC menu).  Pay attention to the order of the arguments---as both users and rooms are just JIDs, it is technically possible to invite a room to a user, but that's probably not what you want.

When you receive an invitation, it appears in the chat buffer along with two buttons, ``Accept'' and ``Decline''.  Pressing ``Accept'' enters the room, as you would expect.  Pressing ``Decline'' gives you an opportunity to state the reason why you're not joining.

Private messages
================

You can open a private chat with a participant in a chat room with M-x jabber-muc-private (or by using the MUC menu).  This creates a buffer with the name *-jabber-muc-priv-GROUP-NICKNAME-* (customizable by jabber-muc-private-buffer-format), which behaves mostly like an ordinary chat buffer.  This buffer will also be created if someone sends a private message to you.

Private MUC messages use the same alerts as normal chat messages. See Message alerts.

Administration
==============

Administration of a MUC room mostly consists of managing roles and affiliations.  Roles are temporary, and apply until the user leaves the room.  Affiliations are permanent, and based on JIDs.

Roles
-----

If you have moderator privileges, you can change the role of a participant with M-x jabber-muc-set-role.  Kicking means setting the role to ``none''.  Granting and revoking voice are ``participant'' and ``visitor'', respectively.  ``moderator'' gives moderator privileges, obviously.

The possible roles are:

moderator
     Has voice, can change other people's roles.

participant
     Has voice.

visitor
     Doesn't have voice (can't send messages to everyone, but can send private messages)

none
     Not in room.

Affiliations
------------

If you have admin or owner privileges, you can change the affiliation of a user with M-x jabber-muc-set-affiliation.  Affiliation is persistent, and based on JIDs.  Depending of your affiliation and the MUC implementation, you might not be allowed to perform all kinds of changes, and maybe not in one step.

Affiliations are:

owner
     Can destroy room, appoint admins, make people members, ban people.

admin
     Can make people members or ban people.

member
     Can enter the room, and has voice by default.

none
     Rights depend on room configuration.  The room might be members-only, or grant voice only to members.

outcast
     Banned from the room.

Composing messages
******************

The chat buffer interface can be inconvenient for some purposes.  As you can't use RET to insert a newline (use C-j for that), writing a longer message can be painful.  Also, it is not possible to include a subject in the message, or send the message to multiple recipients.

These features are implemented by the message composing tool.  Type M-x jabber-compose to start it.  In the buffer that comes up, you can specify recipients, enter a subject, and type your message.

File transfer
*************

jabber.el has limited support for file transfer.  The most important limit is that files sent and received are kept in buffers, so Emacs must be able to allocate enough memory for the entire file, and the file size must be smaller than the maximum buffer size. (The maximum buffer size depends on in the variable most-positive-fixnum.  On 32-bit systems, this is 128 or 256 megabytes, depending on your Emacs version.)

jabber.el is able to exchange files with most Jabber clients (and also some MSN transports), but notably not with the official Google Talk client.  The Google Talk client uses a different file transfer protocol which, at the time of this release, has not been published.

Receiving files
===============

Receiving files requires no configuration.  When someone wants to send a file to you, you are asked (through yes-or-no-p) whether you want to accept the file.  If you answer yes, you get to choose where to save the file.

If the sender's client is correctly configured (this is often not the case; see below), the file transfer will start.  Currently, the only way to watch the progress is to inspect the buffer of the file being transfered; C-x C-b is one way of doing that.  See Listing Existing Buffers (GNU Emacs Manual).  When the transfer is done, the message ``FILE downloaded'' appears in the echo area, and the buffer is killed.

If this doesn't happen, it is most likely the sender's fault.  The sender needs to have a public IP address, either directly, through port forwarding (in which case the client needs to be configured with the real public IP address), or through an XEP-0065 proxy.  If you have activated XML logging (see Debug options), you can see the IP address that the other client is asking you to connect to there.  Often you will find that this is an internal IP address (often starts with 192.168).  See the documentation of the sender's client for setting this up.

Sending files
=============

To send a file to someone, you need an XEP-0065 proxy. (This requirement is not inherent in the protocol, only in the current file transfer implementation of jabber.el, and in Emacs versions earlier than 22.)  If your Jabber server hosts such a proxy, it will be found automatically, otherwise it needs to be manually configured.

You can check whether your Jabber server has a proxy with M-x jabber-get-disco-items; see Service discovery.

To configure a proxy manually, customize the variable jabber-socks5-proxies.  Putting proxy.jabber.se there should work.  Type M-x jabber-socks5-query-all-proxies to see if the proxies answer.

Now, you can type M-x jabber-ft-send to send a file to someone. You need to enter the correct full JID, including resource, to get this right.  If the contact is logged in with only one client, and you can see it online, just typing the JID or roster name is enough.  If you run the command from a chat buffer, the JID of the contact is given as the default value.

If the contact has several clients online, you probably want to send the file to a particular one.  If you run this command from within a chat buffer, the default target will be the one that last sent a message to you.  If you just type a bare JID or a roster name, the client with the highest priority will get the file.

If the contact accepts the file, and the contact's client succeeds in connecting to the proxy, jabber.el will send the file through the proxy.  During this time, your Emacs will be blocked, so you might want to avoid sending large files over slow connections.

Services
********

Not every Jabber entity is a physical person.  There are many automatic entities, called servers, services, components, agents, transports and other names.  The use of these is described here.

The functions described in this chapter use browse buffers. Browse buffers are named *-jabber-browse-:-SERVICE-*, sometimes with a numerical suffix.  The different menus have the same keybindings as in the roster buffer, and if you call a function operating on a JID while point is over a JID, that JID will be the default value, so you don't have to type it or copy it yourself.

You can change the buffer name template by customizing the variable jabber-browse-buffer-format.

Commands
========

A small number of commands is used for almost all interaction with Jabber services.  Essentially, they are all the same: you request a form from the server, fill it in, and send it back.

Most of these commands are available under the Service menu, which is opened by typing C-c C-s.  Service discovery is under the Info menu instead, which is available under C-c C-i.

Registration
------------

You can get a registration form for a service by typing M-x jabber-get-register and entering the JID of the service.  On success, you get a single-stage form to fill in.

There are two buttons at the bottom of the form, ``Submit'' and ``Cancel registration''.  ``Submit'' does what you would expect it to, but ``Cancel registration'' cancels any existing registration with the service.  Whichever of them you choose, you get a message in the echo area informing whether the operation succeeded.

Search
------

You can get a search form for a service by typing M-x jabber-get-search.  This gives you a single-stage form to fill in. After you press the ``Submit'' button at the bottom, the search results will be displayed in the same buffer.

Ad-Hoc Commands
---------------

jabber.el supports a subset of XEP-0050, the standard for Ad-Hoc Commands.  As the name implies, this can be used for just about anything.  In particular, it is used not only by services, but also by clients (e.g. Psi, and jabber.el itself).

To find which commands are available, run ``Request command list'' (jabber-ahc-get-list). (This is the same thing as a disco items request to the node http://jabber.org/protocol/commands.)

To run a command from the list, put point over it and run ``Execute command'' (jabber-ahc-execute-command), accepting the defaults for JID and node.  (If you already know those, you could of course enter them yourself.)

What happens next depends on the command and the service.  In some cases, the service just responds that the command has been run.  You may also get a form to fill out.  This form may have multiple stages, in which case there are ``Next'' and ``Previous'' buttons for navigating between stages.  You may also see ``Complete'', which runs the command skipping any remaining stages of the form, and ``Cancel'', which cancels the command.

Currently, jabber.el uses ad-hoc commands for setting presence remotely. If you realize that you forgot to set your client to ``away'' with a low priority, you can do it remotely from any JID from jabber-account-list. So, you can add disabled JIDs in jabber-account-list to allow them control your presence. (Most Jabber servers also support kicking a client off the net by logging in with another client with exactly the same resource.)

Service discovery
-----------------

Service discovery is used to find information about servers, services and clients.  There are two kinds of requests: find info about a Jabber entity---i.e. its identity and supported features---and find items related to an entity, where the definition of ``related'' is left to the entity itself.

The commands to execute such requests are jabber-get-disco-info and jabber-get-disco-items, respectively.  These commands can be accessed from the Info menu, which is opened by typing C-c C-i. The commands accept a JID and optionally a ``node''.

The result of such a command is displayed in a browse buffer.  For an info request, the result just lists the identities and features of the entity.  For an item request, the related items are listed.  The items may be JIDs, or JIDs with a node.  If you put point on one of the items, its JID and node will be the default value for any Jabber command.

If you think that the interface to service discovery is awkward and should be replaced with something better, you are completely right.

Browsing
--------

Before service discovery, browsing was the way to find information about Jabber entities.  Nowadays it is all but superseded, but jabber.el still supports it.  You can use it by typing M-x jabber-get-browse.  It works much like service discovery.

Your home server
================

You can interact with your Jabber server to change your password or remove your account.  Both of these can be accomplished by typing M-x jabber-get-register and typing the JID of your server; see Registration.

Transports to other IM networks
===============================

Some Jabber services make it possible to communicate with users on other instant messaging networks (e.g. MSN, ICQ, AIM), in effect turning your Jabber client into a multi-protocol client.  These are called gateways or transports.  They work by impersonating you on the legacy network; therefore you need to provide your username and password through registration.

Finding a transport
-------------------

To use such a transport, you first need to find one, obviously. Sometimes your home server provides the transports you need, but you are not limited to those; in principle you can use any transport on the Jabber network.  Some transports only accept local users, though.

Transports are generally mentioned on the web page of the Jabber server in question.  You can also find transports from within the client; see Service discovery.

Registering with a transport
----------------------------

To register with a transport, type M-x jabber-get-register and enter the JID of the transport.  This will open a registration form where you get to fill in your login information; see Registration. You can later use this same form to change the information or cancel your registration.

After you have registered, the transport will request presence subscription.  It needs that to know when you are online, and synchronize your presence on the legacy network.

Contact list
------------

Once you are registered, the transport will transfer the contact list from the legacy service.  From the Jabber side, it appears as if lots of people suddenly request presence subscription to you.  This is somewhat inconvenient, but it is currently the only way that the transport can influence your Jabber contact list, as it is an entity external to your server. (Of course, jabber.el could do more to alleviate this inconvenience.)

When you have accepted these presence subscriptions, the contacts from legacy networks appear as if they were Jabber contacts.

Finding users
-------------

Some legacy networks have a global database of users, and some transports support searching that database.  In that case, you can search for other users with M-x jabber-get-search; see Search.

User directories
================

There are some Jabber user directories, usually abbreviated JUDs.  The most well-known one is users.jabber.org.  You can register with such a directory to let other people find you (see Registration), and you can search the directory (see Search).

MUC services
============

MUC services (Multi-User Chat, chat rooms) are usually not operated by these commands, but by commands specific to the MUC protocol; see Groupchat.  However, some MUC services offer nickname registration through the registration protocol (see Registration), and other commands; see Ad-Hoc Commands.

Personal information
********************

The Jabber way of handling personal information (name, addresses, phone numbers, etc) is ``vCards'' encoded in XML. (See XEP-0054.) You can get information about a user by running M-x jabber-vcard-get, and you can edit your own information by running M-x jabber-vcard-edit.

The form for editing your information can be slightly confusing---you are allowed to enter any number of addresses, phone numbers and e-mail addresses, each of which has a set of orthogonal properties.  You can add and remove items with the [INS] and [DEL] buttons, respectively.

This is also where you set your avatar (see Avatars).  The size of your avatar file is limited to 8 kilobytes.

Avatars
*******

jabber.el supports viewing and publishing avatars according to XEP-0153, vCard-Based Avatars.  By default, if you have an avatar in your vCard (see Personal information), it will be published for others to see, and if other people publish their avatars, they will be displayed in the roster buffer and in the header line of chat buffers, if your Emacs can display images.  Otherwise, jabber.el will not fetch avatars at all.

To disable retrieval of other people's avatars, set jabber-vcard-avatars-retrieve to nil.  To disable publishing of your own avatar, set jabber-vcard-avatars-publish to nil.  To disable avatars in chat buffer header lines, set jabber-chat-buffer-show-avatar to nil.

There are a number of restrictions on avatar images in the specification.  Most of them are not enforced by jabber.el.

  * The image should be smaller than 8 kilobytes; this is enforced by jabber.el.

  * The image height and width should be between 32 and 96 pixels; the recommended size is 64 by 64 pixels.

  * The image should be square.

  * The image should be in either PNG, GIF, or JPEG format.  (jabber.el will behave incorrectly if the image is not in a format supported by Emacs.)

Avatars are cached in the directory specified by jabber-avatar-cache-directory, by default ~/.jabber-avatars/.  The cache is never cleaned, so you might want to do that yourself from time to time.

Time queries
************

With M-x jabber-get-time, you can ask what time an entity (client, server or component) thinks it is, and what time zone it thinks it is in.

You can query a server about when a certain user was last seen online. Use M-x jabber-get-last-online for that.

You can also ask a client about how long a user has been idle with M-x jabber-get-idle-time.  Not all clients answer such queries, e.g. jabber.el doesn't.  This command can also tell the uptime of a server or component.

The first of these commands uses the old Entity Time protocol (see XEP-0090).  It has been superseded by XEP-0202, but jabber.el doesn't implement the newer protocol yet.  The latter two commands use the Last Activity protocol (see XEP-0012).

Useful features
***************

jabber.el includes a number of features meant to improve the user interface and do other useful things.

Autoaway
========

It is possible to automatically set your status to ``away'' when you haven't used your computer for a while.  This lets your contacts know that you might not answer immediately.

To activate this feature, add jabber-autoaway-start to jabber-post-connect-hooks, e.g:

     (add-hook 'jabber-post-connect-hooks 'jabber-autoaway-start)

There are different methods to find how long you have been ``idle''. The method to use is specified by jabber-autoaway-method.  The value of this variable should be a function that returns the number of seconds you have been idle.  Three functions are provided.

If your Emacs has the current-idle-time function (which was introduced in Emacs 22), it is used by default.  Note that this method only measures the time since you last interacted with Emacs, and thus disregards activity in other programs.

If you are using the X Window System, you can use the xprintidle program. (http://www.dtek.chalmers.se/~henoch/text/xprintidle.html) Make sure that jabber-xprintidle-program is set to the correct file name.  This uses the same method as XScreensaver (http://www.jwz.org/xscreensaver) to find your idle time.

If you use the xscreensaver program, you can use the xscreensaver-emacs-jabber Perl script to synchronize xscreensaver and jabber.el status. It is a simple Perl daemon that watches for xscreensaver status and sets jabber.el's presence when needed.  I.e.: it sets XA presence when the screen is blanked or locked (by hands or by idle timeout) and default presence when it's unlocked/unblanked. To use it, just run xscreensaver-emacs-jabber after xscreensaver and make sure that your Emacs run in server mode (that you run (server-start) in init files; see Using Emacs as a Server (GNU Emacs Manual).  Alternatively, you can turn on and off server-mode by jabber.el's hooks).

If you are using Emacs on a GNU/Linux terminal, the function jabber-termatime-get-idle-time is used by default.  It uses the access time of the terminal device as a measure of idle time.

Modeline status
===============

By typing M-x jabber-mode-line-mode you toggle display of some status in mode lines.  The information is your own presence status, and some numbers showing the status of your roster contacts.  By default, there are three numbers, for ``online'' (chatty and online), ``away'' (away, extended away and do not disturb) and offline contacts.

If you set jabber-mode-line-compact to nil, you get a complete breakdown of presence status.  That gives you six numbers indicating the number of chatty, online, away, extended away, dnd, and offline contacts, respectively.

Keepalive
=========

Sometimes network connections are lost without you noticing.  This is especially true with Jabber, as it is quite reasonable to keep the connection open for a long time without either sending or receiving any data.

If you want to detect a lost connection earlier, you can use the keepalive functions.  Type M-x jabber-keepalive-start to start it, and M-x jabber-keepalive-stop to stop it.

These functions work by asking your server for the time once in a while (by default every ten minutes), and considering the connection lost if the server doesn't answer within reasonable time (by default 20 seconds).

You can customize the interval and the timeout with the variables jabber-keepalive-interval and jabber-keepalive-timeout, respectively.

Reconnecting
============

jabber.el supports automatic reconnection to Jabber server(s) upon lost connection.  By default it is off.  To turn on, customize the jabber-auto-reconnect variable.

This is of limited use if you have to type your password every time jabber.el reconnects.  There are two ways to save your password: you can set it in jabber-account-alist (see Account settings), and you can use password-cache.el, which is available in recent versions of Gnus and in Emacs 23.  Note that you probably want to customize password-cache-expiry if you use the latter.

Tracking activity
=================

When you're working on something important you might want to delay responding to incoming messages.  However, when you're done working, will you remember them?  If you're anything like me, you'll have a lot of buffers in your Emacs session, and a Jabber chat buffer can easily get lost.

When jabber-activity-mode is enabled (by default, it is), Emacs keeps track of the buddies which have messaged you since last you visited their buffer, and will display them in mode line.  As soon as you visit their buffer they disappear from the mode line, indicating that you've read their message.

If your mode line fills over because of these notifications, you can customize jabber-activity-make-strings to shorten them to the shortest possibly unambiguous form.

If you try to exit Emacs while you still have unread messages, you will be notified and asked about this.  If you don't like that, set jabber-activity-query-unread to nil.

If you want to display the number of unread buffers in the frame title, set jabber-activity-count-in-title to t.  The format of the number can be changed through jabber-activity-count-in-title-format.

To hide activity notifications for some contacts, use jabber-activity-banned variable - just add boring JIDs (as regexps) here.

For complete customizability, write a hook function for jabber-activity-update-hook.  From that function, you can take action based on jabber-activity-jids, jabber-activity-mode-string, and jabber-activity-count-string.

Watch buddies
=============

Sometimes you might be waiting for a certain person to come online, and you don't want that occasion to get lost in the noise.  To get an obtrusive message when that happens, type M-x jabber-watch-add and select the person in question.  You can enter a comment, to remember why you added the watch.

You will get a message whenever that person goes from offline to online.  jabber.el will remember this for the rest of your Emacs session (it's not saved to disk, though), but if you want to get rid of it, type M-x jabber-watch-remove.

Spell checking
==============

You can activate spell checking in a chat buffer with M-x flyspell-mode.  It will check only what you are currently writing, not what you receive or what you have already sent.  You may want to add flyspell-mode to jabber-chat-mode-hook.

For more information about Emacs spell checking, see Checking and Correcting Spelling (GNU Emacs Manual).

Message history
***************

If you want a record of messages sent and received, set jabber-history-enabled to t.  By default all messages will be saved to a global history file specified by jabber-global-history-filename (~/.jabber_global_message_log by default).  If you prefer to store your chats' history in per-contact files, you can set jabber-use-global-history to nil.  When using per-contact history, files are named by the contact JID and saved under the directory specified by the variable jabber-history-dir (default is ~/.emacs-jabber).

When you open a new chat buffer and have entries in your history file, the last few messages you recently exchanged with the contact in question will be inserted.  You can control how many messages with jabber-backlog-number (by default 10), and how old messages with jabber-backlog-days (by default 3 days).

If you want to see more messages, use the function jabber-chat-display-more-backlog, available in the Chat menu. This is currently the only way to view the message history, apart from opening the history files manually.

If you worry about your history file(s) size, you can enable history rotation feature by setting the variable jabber-history-enable-rotation to t (default is nil).  This feature ``rotates'' your history files according to the following rule: When jabber-history-size-limit (in kilobytes) is reached, the HISTORY-FILE is renamed to HISTORY-FILE-NUMBER, where NUMBER is 1 or the smallest number after the last rotation.

For example, suppose you set the jabber-history-size-limit variable to 512 and you chat with your buddy foo@jabber.server using the per-contact strategy to store history files.  So, when the history file (foo@jabber-server) reaches 512K bytes, it will be renamed to foo@jabber-server-1 and foo@jabber-server will be set empty. Next time foo@jabber-server grows to 512K bytes, it will be saved as foo@jabber-server-2 and so on.  Although the example was presented with the per-contact history file strategy, history rotation works for both per-contact and global history logging strategies.

If you also want to keep chat and groupchat buffers from growing too much, you can customize jabber-alert-message-hooks and jabber-alert-muc-hooks by adding truncation upon receiving message (jabber-truncate-chat and jabber-truncate-muc, respectively). The truncation limit may be set by customizing the variable jabber-log-lines-to-keep.

Typing notifications
********************

There are two protocols for ``contact is typing'' notifications in Jabber.  jabber.el supports both of them, displaying various information in the header line of chat buffers.

Message events
==============

The older protocol is called Message Events (see XEP-0022).  Besides typing notification, it lets you know what happens to the messages you send. These states are possible:

  * In offline storage (the user will receive it on next logon)

  * Delivered to user's client (but not necessarily displayed)

  * Displayed to user

  * User is typing a message

The first state is only reported by servers; the other three are reported by clients.  jabber.el can report all three of them, and can display all four; not all clients support all states, though.

If you don't want jabber.el to send out this information about you, set the variables jabber-events-confirm-delivered, jabber-events-confirm-displayed, and/or jabber-events-confirm-composing to nil.  You can make jabber.el not to request such information by customizing jabber-events-request-these.

Chat states
===========

The newer protocol is called Chat States (see XEP-0085).  Rather than dealing with individual messages, it describes the state of the chat session between two people.  The following states are possible:

  * Active (the default state, not displayed)

  * Inactive

  * Composing

  * Paused (i.e., taking a short pause in composing)

  * Gone

jabber.el can display all five states, but only ever sends ``active'' and ``composing'' itself.

To customize sending of chat states, customize the variable jabber-chatstates-confirm.

Roster import and export
************************

Your roster is saved on the Jabber server, and usually not in the client.  However, you might want to save the roster to a file anyway. The most common reason for this is probably to copy it to another account.

To export your roster to a file, type M-x jabber-export-roster. A buffer will appear in which you can edit the data to be exported. Changes done in that buffer will not affect your real roster.

To import your roster from a file, type M-x jabber-import-roster. You will be able to edit the data before importing it.  Items not in the roster will be added; items in the roster will be modified to match imported data.  Subscriptions will be updated.

The format of the roster files is the XML used by roster pushes in the XMPP protocol, in UTF-8 encoding.

XMPP URIs
*********

Many web page authors use links starting with xmpp: for JIDs. Your web browser could be made to pass such links to jabber.el, so that such links are actually useful and not just decoration.  How to do that depends on your operating system and web browser.

Mozilla and Unix
================

If you use a Mozilla-based web browser on a Unix-like operating system, follow these steps.

 1. Make sure you are running the Emacs server.  See Using Emacs as a Server (GNU Emacs Manual).

 2. Note the path of the xmppuri.sh file in the jabber.el distribution, and make sure it is executable.

 3. Set the Mozilla preference network.protocol-handler.app.xmpp to the path of xmppuri.sh.  There are two ways to do this:

       * Go to the URL about:config, right-click in the list, choose ``New string'', and enter network.protocol-handler.app.xmpp and the path in the following dialogs.

       * Open or create the file user.js in your Mozilla profile directory (in the same directory as prefs.js), and add the following line:

               user_pref("network.protocol-handler.app.xmpp",
                 "/PATH/TO/xmppuri.sh");

          Restart Mozilla for this change to take effect.

Other systems
=============

If you know how to pass an XMPP URI from your browser to the function jabber-handle-uri, your contribution for this section would be appreciated.

Customization
*************

jabber.el is intended to be customizable for many tastes.  After all, this is Emacs.  To open a customization buffer for jabber.el, type M-x jabber-customize.

Account settings
================

All account settings reside in the variable jabber-account-list. Usually you only need to set the JID, in the form username@server (or username@server/resource to use a specific resource name).  These are the other account options:

Disabled
     If the account is disabled, jabber-connect-all will not attempt to connect it.  You can still connect it manually with jabber-connect.

Password
     You can set the password of the account, so you don't have to enter it when you connect.  Note that it will be stored unencrypted in your customization file.

Network server
     If the JID of the Jabber server is not also its DNS name, you may have to enter the real DNS name or IP address of the server here.

Connection type
     This option specifies whether to use an encrypted connection to the server.  Usually you want ``STARTTLS'' (starttls), which means that encryption is activated if the server supports it.  The other possibilities are ``unencrypted'' (network), which means just that, and ``legacy SSL/TLS'' (ssl), which means that encryption is activated on connection.

Port
     If the Jabber server uses a nonstandard port, specify it here.  The default is 5222 for STARTTLS and unencrypted connections, and 5223 for legacy SSL connections.

For Google Talk
---------------

If you have a very new version of dns.el, (Specifically, you need Emacs 23, or No Gnus 0.3.) you can connect to Google Talk just by specifying your Gmail address as JID.  Otherwise, you also need to set ``network server'' to talk.google.com and ``connection type'' to ``legacy SSL''.

Upgrade note
------------

Previous versions of jabber.el had the variables jabber-username, jabber-server, jabber-resource and jabber-password.  These are now obsolete and not used.

Menu
====

If you want a Jabber menu on the menu bar with some common commands, type M-x jabber-menu.  You can remove it again with C-u M-x jabber-menu.  Unfortunately, this cannot be changed through Customize settings, so you need to add (jabber-menu) to your .emacs to enable it permanently.

Customizing the roster buffer
=============================

jabber-roster-sort-functions controls how roster items are sorted.  By default, contacts are sorted first by presence, and then alphabetically by displayed name.

jabber-sort-order controls how roster items are sorted by presence.  It is a list containing strings corresponding to show status (see Presence) or nil, which represents offline.

jabber-show-resources controls when your contacts' resources are shown in the roster buffer.  The default is to show resources when a contact has more than one connected resource.

jabber-roster-line-format specifies how the entry for each contact looks.  It is a string where some characters are special if preceded by a percent sign:

%a
     Avatar of contact, if any

%c
     * if the contact is connected, or   if not

%u
     Subscription state---see below

%n
     Nickname of contact, or JID if no nickname

%j
     Bare JID of contact (without resource)

%r
     Highest-priority resource of contact

%s
     Availability of contact as a string ("Online", "Away" etc)

%S
     Status string specified by contact

%u is replaced by one of the strings given by `jabber-roster-subscription-display'.

jabber-resource-line-format is nearly identical, except that the values correspond to the values of the resource in question, and that the %p escape is available, which inserts the priority of the resource.

jabber-roster-buffer specifies the name of the roster buffer. If you change this, the new name will be used the next time the roster is redisplayed.

jabber-roster-show-bindings controls whether to show a list of keybindings at the top of the roster buffer.  You need to run M-x jabber-display-roster after changing this variable to update the display.

Customizing the chat buffer
===========================

You can customize the look of the prompts in the chat buffer.  There are separate settings for local text (i.e. what you write) and foreign text (i.e. what other people write).

jabber-chat-text-local and jabber-chat-text-foreign determine the faces used for chat messages.

jabber-chat-prompt-local and jabber-chat-prompt-foreign determine the faces used for the prompts.

jabber-chat-local-prompt-format and jabber-chat-foreign-prompt-format determine what text is displayed in the prompts.  They are format strings, with the following special sequences defined:

%t
     The time when the message was sent or received

%n
     The nickname of the user.  For the foreign prompt, this is the name of the contact in the roster, or the JID if no name set.  For the local prompt, this is the username part of your JID.

%u
     The username of the user (i.e. the first part of the JID).

%r
     The resource.

%j
     The bare JID of the user

jabber-chat-time-format defines how %t shows time.  Its format is identical to that passed to format-time-string. See Time Conversion (GNU Emacs Lisp Reference Manual).

jabber-chat-delayed-time-format is used instead of jabber-chat-time-format for delayed messages (messages sent while you were offline, or fetched from history).  This way you can have short timestamps everywhere except where you need long ones.  You can always see the complete timestamp in a tooltip by hovering over the prompt with the mouse.

By default, timestamps are printed in the chat buffer every hour (at ``rare'' times).  This can be toggled with jabber-print-rare-time.  You can customize the displayed time by setting jabber-rare-time-format.  Rare timestamps will be printed whenever time formatted by that format string would change.

You can also customize the header line of chat buffers, by modifying the variable jabber-chat-header-line-format.  The format of that variable is the same as that of mode-line-format and header-line-format.  See Mode-Line Format (GNU Emacs Lisp Reference Manual).  For MUC buffers, jabber-muc-header-line-format is used instead.

The variable jabber-chat-fill-long-lines controls whether long lines in the chat buffer are wrapped.

Customizing alerts
==================

When an event happens (currently including presence changes, incoming messages, and completed queries) you will usually want to be notified.  Since tastes in this area vary wildly, these alerts are implemented as hooks, so you can choose which ones you want, or write your own if none fit.

Actually, if you don't want to write your own, stop reading this section and just read Standard alerts.

Many kinds of alerts consist in displaying a text message through a certain mechanism.  This text message is provided by a function which you can rewrite or replace.  If this function returns nil, no message is displayed, and non-textual alerts refrain from action.

If you want to write alert hooks that do nothing except displaying the supplied message in some way, use the macro define-jabber-alert.  For example, if FOO is a function that takes a string as an argument, write

     (define-jabber-alert foo
       "Display a message in a fooish way"
       'foo)

and all details will be taken care of for you.

The hooks take different arguments depending on category.  However, they all have in common that the last argument is the result of the message function.  The message function for each category takes the same arguments as the corresponding hooks, except for that last argument.

Alert hook contributions are very welcome.  You can send them to the mailing list, or to the Sourceforge patch tracker.

Alert hooks are meant for optional UI things, that are subject to varying user tastes, and that can be toggled by simply adding or removing the function to and from the hook.  For other purposes, there are corresponding general hooks, that are defvars instead of defcustoms, and that are meant to be managed by Lisp code.  They have the same name as the alert hooks minus the -alert part, e.g. jabber-message-hooks vs jabber-alert-message-hooks, etc.

Standard alerts
---------------

Thirteen alerts are already written for all four alert categories.  These all obey the result from the corresponding message function.

The beep alerts simply sound the terminal bell by calling ding.  They are disabled by default.

The echo alerts display a message in the echo area by calling message.  They are enabled by default.

The switch alerts switch to the buffer where the event occurred (chat buffer for incoming messages, roster buffer for presence changes, browse buffer for completed queries).  They are disabled by default.  Take care when using them, as they may interrupt your editing.

The display alerts display but do not select the buffer in question, using the function display-buffer.  See Choosing a Window for Display (GNU Emacs Lisp Reference Manual), for information about customizing its behaviour. This is enabled by default for info requests.

The wave alerts play a sound file by calling play-sound-file.  No sound files are provided.  To use this, enter the names of the sound files in jabber-alert-message-wave, jabber-alert-presence-wave and jabber-alert-info-wave, respectively.  You can specify specific sound files for contacts matching a regexp in the variables jabber-alert-message-wave-alist and jabber-alert-presence-wave-alist.

The screen alerts send a message through the Screen terminal manager (See http://www.gnu.org/software/screen/.).  They do no harm if called when you don't use Screen.

The ratpoison alerts send a message through the Ratpoison window manager (See http://ratpoison.sourceforge.net/.).  They do no harm if used when you're not running X, but if you are running X with another window manager, the ratpoison processes will never exit. Emacs doesn't hold on to them, though.

The sawfish alerts send a message through the Sawfish window manager.

The wmii alerts display a message through the wmii window manager.

The xmessage alerts send a message through the standard xmessage tool.  The variable jabber-xmessage-timeout controls how long the alert appears.

The osd alerts send a message onto your screen using XOSD. (XOSD can be found at http://www.ignavus.net/software.html.  You also need osd.el from http://www.brockman.se/software/osd.el.)

The libnotify alerts send a message onto your screen using notification-daemon.

The festival alerts speak the message using the Emacs interface of the Festival speech synthesis system (See http://www.cstr.ed.ac.uk/projects/festival/.).

The autoanswer alert is kind of special: it will not show you message/muc alert, but instead will automaticaly answer to sender. See variable `jabber-autoanswer-alist' description for details.

Additionally, for one-to-one and MUC messages, there are scroll alerts (enabled by default), that aim to do the right thing with chat buffers that are visible but not active.  Sometimes you want point to scroll down, and sometimes not.  These functions should do what you mean; if they don't, it's a bug.

Also, in MUC you can use a family of so-called ``personal'' alerts. They are like other MUC alerts, but fire only on incoming messages addresed directly to you (also known as ``private messages'').  One example of such an alert is jabber-muc-echo-personal, which shows a note for an MUC message only if it was addressed to you.

Some of these functions are in the jabber-alert.el file, and the others are in their own files.  You can use them as templates or inspiration for your own alerts.

Presence alerts
---------------

Set jabber-alert-presence-message-function to your desired function.  This function should look like:

     (defun FUNCTION (WHO OLDSTATUS NEWSTATUS STATUSTEXT)
        ...
        )

WHO is the JID symbol (see JID symbols), OLDSTATUS and NEWSTATUS are the previous and current stati, respectively, and STATUSTEXT is the status message if provided, otherwise nil.

OLDSTATUS and NEWSTATUS can be one of "" (i.e. online), "away", "xa", "dnd", "chat", "error" and nil (i.e. offline).

NEWSTATUS can also be one of "subscribe", "subscribed", "unsubscribe" and "unsubscribed".

The default function, jabber-presence-default-message, returns nil if OLDSTATUS and NEWSTATUS are the same, and in other cases constructs a message from the given data.

All presence alert hooks take the same arguments plus the additional PROPOSED-ALERT, which is the result of the specified message function.  This last argument is usually the only one they use.

Message alerts
--------------

Set jabber-alert-message-function to your desired function. (Logically it should be jabber-alert-message-message-function, but that would be really ugly.)  This function should look like:

     (defun FUNCTION (FROM BUFFER TEXT)
        ...
        )

FROM is the JID symbol (see JID symbols), BUFFER is the buffer where the message is displayed, and TEXT is the text of the message.

The default function, jabber-message-default-message, returns ``Message from PERSON'', where PERSON is the name of the person if specified in the roster, otherwise the JID.

All message alert hooks take the same arguments plus the additional PROPOSED-ALERT, which is the result of the specified message function.

If you don't want message alerts when the chat buffer in question is already the current buffer, set jabber-message-alert-same-buffer to nil.  This affects the behaviour of the default message function, so you'll have to reimplement this functionality if you write your own message function.

MUC alerts
----------

Set jabber-alert-muc-function to your desired function.  This function should look like:

     (defun FUNCTION (NICK GROUP BUFFER TEXT)
        ...
        )

NICK is the nickname, GROUP is the JID of the group, BUFFER is the buffer where the message is displayed, and TEXT is the text of the message.

The default function, jabber-muc-default-message, returns ``Message from NICK in GROUP'' or ``Message in GROUP'', the latter for messages from the room itself.

All MUC alert hooks take the same arguments plus the additional PROPOSED-ALERT, which is the result of the specified message function.

By default, no alert is made for messages from yourself.  To change that, customize the variable jabber-muc-alert-self.

Info alerts
-----------

Info alerts are sadly underdeveloped.  The message function, jabber-alert-info-message-function, takes two arguments, INFOTYPE and BUFFER.  BUFFER is the buffer where something happened, and INFOTYPE is either 'roster for roster updates, or 'browse for anything that uses the browse buffer (basically anything except chatting).

The info alert hooks take an extra argument, as could be expected.

Hooks
=====

jabber.el provides various hooks that you can use for whatever purpose.

jabber-post-connect-hooks
     This hook is called after successful connection and authentication. By default it contains jabber-send-current-presence (see Presence).  The hook functions get the connection object as argument.

jabber-lost-connection-hooks
     This hook is called when you have been disconnected for unknown reasons.  Usually this isn't noticed for quite a long time.

     The hook is called with one argument: the connection object.

jabber-pre-disconnect-hook
     This hook is called just before voluntary disconnection, i.e. in jabber-disconnect, the command to disconnect all accounts.  There is currently no hook for disconnection of a single account.

jabber-post-disconnect-hook
     This hook is called after disconnection of any kind, possibly just after jabber-lost-connection-hook.

jabber-chat-mode-hook
     This hook is called when a new chat buffer is created.

jabber-browse-mode-hook
     This hook is called when a new browse buffer is created.

jabber-roster-mode-hook
     This hook is called when the roster buffer is created.

Debug options
=============

These settings provide a lot of information which is usually not very interesting, but can be useful for debugging various things.

jabber-debug-log-xml activates XML logging.  All XML stanzas sent and received are logged in the buffer *-jabber-xml-log-JID-* in list format.  See XML representation.

Usually, the process buffers for Jabber connections are killed when the connection is closed, as they would otherwise just fill up memory. However, they might contain information about why the connection was lost.  To keep process buffers, set jabber-debug-keep-process-buffers to t.

Hacking and extending
*********************

This part of the manual is an attempt to explain parts of the source code.  It is not meant to discourage you from reading the code yourself and trying to figure it out, but as a guide on where to look.  Knowledge of Jabber protocols is assumed.

Connection object
=================

Each Jabber connection is represented by a ``connection object''.  This object has the form of a finite state machine, and is realized by the library fsm. (So far, this library is only distributed with jabber.el.  The author hopes that it could be useful for other projects, too.)

The various states of this object are defined in jabber-core.el. They describe the way of the connection through the establishing of a network connection and authentication, and finally comes to the :session-established state where ordinary traffic takes place.

These details are normally opaque to an extension author.  As will be noted, many functions expect to receive a connection object, and functions at extension points generally receive such an object in order to pass it on.  The following functions simply query the internal state of the connection:

 -- Function: jabber-connection-jid connection
     The jabber-connection-jid function returns the full JID of CONNECTION, i.e. a string of the form "username@server/resource".

 -- Function: jabber-connection-bare-jid connection
     The jabber-connection-bare-jid function returns the bare JID of CONNECTION, i.e. a string of the form "username@server".

XML representation
==================

The XML representation is the one generated by xml.el in Emacs, namely the following.  Each tag is a list.  The first element of the list is a symbol, the name of which is the name of the tag.  The second element is an alist of attributes, where the keys are the attribute names in symbol form, and the values are strings.  The remaining elements are the tags and data contained within the tag.

For example,

     <foo bar='baz'>
     <frobozz/>Fnord
     </foo>

is represented as

     (foo ((bar . "baz")) (frobozz nil "") "Fnord
     ")

Note the empty string as the third element of the frobozz list.  It is not present in newer (post-21.3) versions of xml.el, but it's probably best to assume it might be there.

 -- Function: jabber-sexp2xml xml-sexp
     This function takes a tag in list representation, and returns its XML representation as a string.  You will normally not need to use this function directly, but it can be useful to see how your sexps will look when sent to the outer, non-Lisp, world.

 -- Function: jabber-send-sexp connection sexp
     This function sends SEXP, an XMPP stanza in list representation, and sends it over CONNECTION.

     You will normally use the functions jabber-send-presence, jabber-send-message and jabber-send-iq instead of this function.

JID symbols
===========

JIDs are sometimes represented as symbols.  Its name is the JID, and it is interned in jabber-jid-obarray.  A roster entry can have the following properties:

xml
     The XML tag received from the server on roster update

name
     The name of the roster item (just like the XML attribute)

subscription
     The subscription state; a string, one of "none", "from", "to" and "both"

ask
     The ask state; either nil or "subscribe"

groups
     A list of strings (possibly empty) containing all the groups the contact is in

connected
     Boolean, true if any resource is connected

show
     Presence show value for highest-priority connected resource; a string, one of "" (i.e. online), "away", "xa", "dnd", "chat", "error" and nil (i.e. offline)

status
     Presence status message for highest-priority connected resource

resources
     Alist.  Keys are strings (resource names), values are plists with properties connected, show, status and priority.

Incoming presence information is inserted in resources, and the information from the resource with the highest priority is inserted in show and status by the function jabber-prioritize-resources.

Listening for new requests
==========================

To listen for new IQ requests, add the appropriate entry in jabber-iq-get-xmlns-alist or jabber-iq-set-xmlns-alist. The key is the namespace of the request, and the value is a function that takes two arguments, the connection object, and the entire IQ stanza in list format. jabber-process-iq reads these alists to determine which function to call on incoming packets.

For example, the Ad-Hoc Commands module contains the following:

     (add-to-list 'jabber-iq-set-xmlns-alist
     	     (cons "http://jabber.org/protocol/commands"
                        'jabber-ahc-process))

To send a response to an IQ request, use (jabber-send-iq CONNECTION SENDER "result" QUERY nil nil nil nil ID), where QUERY is the query in list format. jabber-send-iq will encapsulate the query in an IQ packet with the specified id.

To return an error to the Jabber entity that sent the query, use jabber-signal-error.  The signal is caught by jabber-process-iq, which takes care of sending the error. You can also use jabber-send-iq-error.

Sending new requests
====================

To send an IQ request, use jabber-send-iq.  It will generate an id, and create a mapping for it for use when the response comes.  The syntax is:

     (jabber-send-iq CONNECTION TO TYPE QUERY
                     SUCCESS-CALLBACK SUCCESS-CLOSURE
                     FAILURE-CALLBACK FAILURE-CLOSURE)

SUCCESS-CALLBACK will be called if the response is of type result, and FAILURE-CALLBACK will be called if the response is of type error.  Both callbacks take three arguments, the connection object, the IQ stanza of the response, and the corresponding closure item earlier passed to jabber-send-iq.

Two standard callbacks are provided.  jabber-report-success takes a string as closure item, and reports success or failure in the echo area by appending either succeeded or failed to the string.  jabber-process-data prepares a browse buffer.  If its closure argument is a function, it calls that function with point in this browse buffer.  If it's a string, it prints that string along with the error message in the IQ response.  If it's anything else (e.g. nil), it just dumps the XML in the browse buffer.

Examples follow.  This is the hypothetical Jabber protocol ``frob'', for which only success report is needed:

     (jabber-send-iq connection
                     "someone@somewhere.org" "set"
                     '(query ((xmlns . "frob")))
                     'jabber-report-success "Frobbing"
                     'jabber-report-success "Frobbing")

This will print ``Frobbing succeeded'' or ``Frobbing failed: REASON'', respectively, in the echo area.

The protocol ``investigate'' needs to parse results and show them in a browse buffer:

     (jabber-send-iq connection
                     "someone@somewhere.org" "get"
                     '(query ((xmlns . "investigate")))
                     'jabber-process-data 'jabber-process-investigate
                     'jabber-process-data "Investigation failed")

Of course, the previous example could have used jabber-report-success for the error message.  It's a matter of UI taste.

Service discovery
=================

Your new handlers will likely want to advertise their existence through service discovery.

To have an additional feature reported in response to disco info requests, add a string to jabber-advertised-features.

By default, the service discovery functions reject all requests containing a node identifier with an ``Item not found'' error.  To make them respond, add the appropriate entries to jabber-disco-items-nodes and jabber-disco-info-nodes. Both variables work in the same way.  They are alists, where the keys are the node names, and the values are lists of two items.

The first item is the data to return --- either a list or a function taking the entire IQ stanza and returning a list, this list containing the XML nodes to include in the <query/> node in the response.

The second item is the access control function.  An access control function receives the JID as its only argument, and returns non-nil if access is to be granted.  If nil is specified instead of a function, access is always granted.  One such function is provided, jabber-my-jid-p, which grants access for JIDs where the username and server (not necessarily resource) are equal to those of the user.

Chat printers
=============

Chat printers are functions that print a certain aspect of an incoming message in a chat buffer.  Included are functions for printing subjects (jabber-chat-print-subject), bodies (jabber-chat-print-body, and jabber:x:oob-style URLs (jabber-chat-print-url).  The functions in jabber-chat-printers are called in order, with the entire <message/> stanza as argument, and are expected to call insert if they have anything to add.

For MUC, the functions in jabber-muc-printers are prepended to those in jabber-chat-printers.

Body printers are a subgroup of chat printers.  They are exclusive; only one of them applies to any given message.  The idea is that ``higher-quality'' parts of the message override pieces included for backwards compatibility.  Included are jabber-muc-print-invite and jabber-chat-normal-body; functions for XHTML-IM and PGP encrypted messages may be written in the future.  The functions in jabber-body-printers are called in order until one of them returns non-nil.

Stanza chains
=============

If you really need to get under the skin of jabber.el, you can add functions to the lists jabber-message-chain, jabber-iq-chain and jabber-presence-chain.  The functions in these lists will be called in order when an XML stanza of the corresponding type arrives, with the entire XML stanza passed as the only argument.  Earlier functions can modify the stanza to change the behaviour of downstream functions.

Protocol support
****************

These are the protocols currently supported (in full or partially) by jabber.el.

RFC 3920 (XMPP-CORE)
====================

Most of RFC 3920 is supported, with the following exceptions.

SASL is supported only when an external SASL library from FLIM or Gnus is present.  As SASL is an essential part to XMPP, jabber.el will send pre-XMPP stream headers if it is not available.

None of the stringprep profiles are implemented.  jabber.el changes JIDs to lowercase internally; that's all.

jabber.el doesn't interpret namespace prefixes.

The xml:lang attribute is neither interpreted nor generated.

SRV records are used if a modern version of dns.el is installed.

RFC 3921 (XMPP-IM)
==================

Most of RFC 3921 is supported, with the following exceptions.

Messages of type ``headline'' are not treated in any special way.

The <thread/> element is not used or generated.

Sending ``directed presence'' is supported; however, presence stanzas received from contacts not in roster are ignored.

Privacy lists are not supported at all.

jabber.el doesn't support XMPP-E2E or ``im:'' CPIM URIs.

XEP-0004 (Data Forms)
=====================

XEP-0004 support is good enough for many purposes.  Limitations are the following.

Forms in incoming messages are not interpreted.  See each specific protocol for whether forms are accepted in that context.

``Cancel'' messages are probably not consistently generated when they should be.  This is partly a paradigm clash, as jabber.el doesn't use modal dialog boxes but buffers which can easily be buried.

<required/> elements are not enforced.

The field types ``jid-single'', ``jid-multi'' and ``list-multi'' are not implemented, due to programmer laziness.  Let us know if you need them.

XEP-0012 (Last Activity)
========================

jabber.el can generate all three query types described in the protocol. However, it does not answer to such requests.

XEP-0020 (Feature Negotiation)
==============================

There are no known limitations or bugs in XEP-0020 support.

XEP-0022 (Message Events)
=========================

jabber.el understands all four specified kinds of message events (offline, delivered, displayed, and composing) and by default requests all of them.  It also reports those three events that make sense for clients.

XEP-0030 (Service Discovery)
============================

Service discovery is supported, both as client and server.  When used in the code, service discovery results are cached indefinitely.

XEP-0045 (Multi-User Chat)
==========================

jabber.el supports parts of XEP-0045.  Entering, leaving and chatting work.  So do invitations and private messages.  Room configuration is supported.  Changing roles of participants (basic moderation) is implemented, as is changing affiliations, but requesting affiliation lists is not yet supported.

XEP-0049 (Private XML Storage)
==============================

jabber.el contains an implementation of XEP-0049; however it is not used for anything right now.

XEP-0050 (Ad-Hoc Commands)
==========================

jabber.el is probably the first implementation of XEP-0050 (see post on jdev from 2004-03-10 (http://article.gmane.org/gmane.network.jabber.devel/21413)).  Both the client and server parts are supported.

XEP-0054 (vcard-temp)
=====================

Both displaying other users' vCards and editing your own vCard are supported.  The implementation tries to follow the schema in the XEP accurately.

XEP-0055 (Jabber Search)
========================

XEP-0055 is supported, both with traditional fields and with Data Forms (see XEP-0004).  As the traditional fields specified by the XEP is a subset of those allowed in XEP-0077, handling of those two form types are merged.  See XEP-0077.

XEP-0065 (SOCKS5 Bytestreams)
=============================

XEP-0065 is supported.  Currently jabber.el cannot act as a server, not even on on Emacsen that support server sockets (GNU Emacs 22 and up). Therefore it relies on proxies.  Proxies have to be entered and queried manually.

Psi's ``fast mode'' (http://delta.affinix.com/specs/stream.html), which gives greater flexibility with regards to NAT, is not implemented.

XEP-0066 (Out of Band Data)
===========================

jabber.el will display URLs sent in message stanzas qualified by the jabber:x:oob namespace, as described in this XEP.  Sending such URLs or doing anything with iq stanzas (using the jabber:iq:oob namespace) is not supported.

XEP-0068 (Field Standardization for Data Forms)
===============================================

XEP-0068 is only used in the context of creating a new Jabber account, to prefill the username field of the registration form.

XEP-0077 (In-Band Registration)
===============================

In-band registration is supported for all purposes.  That means registering a new Jabber account, changing Jabber password, removing a Jabber account, registering with a service, and cancelling registration to a service.  Data forms are supported as well.  URL redirections are not.

jabber.el will not prevent or alert a user trying to change a password over an unencrypted connection.

XEP-0078 (Non-SASL Authentication)
==================================

Non-SASL authentication is supported, both plaintext and digest. Digest is preferred, and a warning is displayed to the user if only plaintext is available.

XEP-0082 (Jabber Date and Time Profiles)
========================================

The DateTime profile of XEP-0082 is supported.  Currently this is only used for file transfer.

XEP-0085 (Chat State Notifications)
===================================

XEP-0085 is partially supported. Currently only active/composing notifications are sent though all five notifications are handled on receipt.

XEP-0086 (Error Condition Mappings)
===================================

Legacy errors are interpreted, but never generated.  XMPP style error messages take precedence when errors are reported to the user.

XEP-0090 (Entity Time)
======================

jabber.el can query other entities for their time, and return the current time to those who ask.

XEP-0091 (Delayed Delivery)
===========================

The time specified on delayed incoming messages is interpreted, and displayed in chat buffers instead of the current time.

XEP-0092 (Software Version)
===========================

The user can request the version of any entity.  jabber.el answers version requests to anyone, giving ``jabber.el'' as name, and the Emacs version as OS.

XEP-0095 (Stream Initiation)
============================

XEP-0095 is supported, both incoming and outgoing, except that jabber.el doesn't check service discovery results before sending a stream initiation request.

XEP-0096 (File Transfer)
========================

Both sending and receiving files is supported.  If a suitable program is found, MD5 hashes of outgoing files are calculated and sent.  However, hashes of received files are not checked.  Ranged transfers are not supported.  In-band bytestreams are not yet supported, even though XEP-0096 requires them.

XEP-0146 (Remote Controlling Clients)
=====================================

The ``set-status'' command in XEP-0146 is supported.

XEP-0153 (vCard-Based Avatars)
==============================

vCard-based avatars are supported, both publishing and displaying.  The pixel size limits on avatars are not enforced.