Tcl Scripting HOWTO

Intoduction

NOTA BENE: This documentation is badly out of date for 2.x.

The Gaim Tcl interface provides a Tcl API for many useful gaim functions. Like the perl API, the Tcl API does not provide access to every corner of gaim exposed by the C interface. It does, however, provide a very powerful interface to many of Gaim's functions through a simple to learn and extend scripting language.

If you are not familiar with Tcl, you will probably find it somewhat different from what you are used to. Despite being somewhat unique (more akin to shell programming than other traditional scripting languages such as perl or python), it is simple to learn for beginners and experienced programmers alike. There are numerous books on the subject; we will not discuss it any further here.

Getting Started

The only requirement placed on a Gaim Tcl script by Gaim is the existence of a procedure called plugin_init. This procedure has some limitations placed upon it; it will be parsed and evaluated before the rest of the Tcl script, so it cannot reference any other variables or procedures declared in the script. In practice this is not a problem, as the only thing this procedure should do is return a simple list containing five items: the name of the script, its version number, a summary (just a few words) of its function, a short (longer than the summary, but no more than a couple of sentences if possible) description, the author, and a URL to web page. For example:

proc plugin_init { } {
  return [ list "Example Plugin" \
                "1.0" \
        "Example plugin registration" \
        "Example of how to register a plugin for the Tcl HOWTO" \
        "Ethan Blanton <eblanton@cs.purdue.edu>" \
        "http://pidgin.im/" ]
}

The rest of the script will generally be registration to recieve notification of various Gaim signals (more about this below) and definitions of procedures to be executed when those signals occur.

Interpreter Details

Gaim initializes and drives the Tcl event loop (similar to Tk), meaning that commands like fileevent and after are available and do not require vwait etc. The vwait actually seems to be somewhat broken due to a bug somewhere in the Tcl/Glib event loop glue, and it should not be used for now.

The gaim-specific functions are provided in a statically-linked package called gaim; this means that if you spawn a child interpreter and wish to use the gaim-specific functions, you will need to execute load {} gaim in that interpreter.

Gaim Internal Procedures and Variables

All of the information provided for your use by Gaim will be in the gaim namespace. This means that in order to access it you will either have to import the gaim namespace (e.g. via the command namespace import gaim::*) or reference it explicitly. The following descriptions will reference it explicitly for clarity.

gaim::version

This contains the version of the gaim process which loaded the script.

gaim::account alias account
gaim::account connect account
gaim::account connection account
gaim::account disconnect account
gaim::account find username protocol
gaim::account handle
gaim::account isconnected account
gaim::account list ?option?
gaim::account protocol account
gaim::account username account

The gaim::account command consists of a set of subcommands pertaining to gaim accounts.

alias returns the alias for the account account. If there is no alias for the given account, it returns the empty string.

The subcommand connect connects the named account if it is not connected, and does nothing if it is. In either case, it returns the gc for the account.

connection returns the gc of the given account if it is connected, or 0 if it is not. This gc is the gc used by gaim::connection and other functions.

disconnect disconnects the given account if it is connected, or does nothing if it is.

find finds an account by its username and protocol (as returned by gaim::account username and gaim::account protocol) and returns the account if found, or 0 otherwise.

handle returns the instance handle required to connect to account signals. (See gaim::signal connect).

The isconnected query returns true if the given account is connected and false otherwise.

The list subcommand returns a list of all of the accounts known to Gaim. The elements of this lists are accounts appropriate for the account argument of the other subcommands. The -all option (default) returns all accounts, while the -online option returns only those accounts which are online.

The protocol subcommand returns the protocol ID (e.g. "prpl-msn") for the given account.

The username subcommand returns the username for the account account.

gaim::buddy alias buddy
gaim::buddy handle
gaim::buddy info ( buddy | account username )
gaim::buddy list

gaim::buddy is a set of commands for retrieving information about buddies and manipulating the buddy list. For the purposes of Tcl, a "buddy" is currently a list of several elements, the first of which being the type. The currently recognized types are "group", "buddy", and "chat". A group node looks like:

    { group name { buddies } }
A buddy node is:
    { buddy name account }
And a chat node is:
    { chat alias account }

The alias subcommand returns the alias for the given buddy if it exists, or the empty string if it does not.

handle returns the blist handle for the purposes of connecting signals to buddy list events. (See gaim::signal connect).

info causes gaim to display the info dialog for the given buddy. Since it is possible to request user info for a buddy not in your buddy list, you may also specify a buddy by his or her username and the account through which you wish to retrieve info.

list returns a list of group structures, filled out with buddies and chats as described above.

gaim::connection account gc
gaim::connection displayname gc
gaim::connection handle
gaim::connection list

gaim::connection is a collection of subcommands pertaining to account connections.

account returns the Gaim account associated with gc. This account is the same account used by gaim::account and other commands.

displayname returns the display name (duh) of gc as reported by gaim_connection_get_display_name(gc).

handle returns the gaim connections instance handle. (See gaim::signal connect).

list returns a list of all known connections. The elements of this list are appropriate as gc arguments to the other gaim::connection subcommands or other commands requiring a gc.

gaim::conv_send account who text

gaim::conv is simply a convenience wrapper for gaim::send_im and gaim::conversation write. It sends the IM, determines the from and to arguments for gaim::conversation write, and prints the text sent to the conversation as one would expect. For the curious, you may view the source for it by typing info body gaim::conv_send at a Gaim Commander prompt.

Note that an error in either gaim::send_im or gaim::conversation write will not be caught by this procedure, and will be propagated to the caller.

gaim::conversation find ?-account account? name
gaim::conversation handle
gaim::conversation list
gaim::conversation new ?-chat? ?-im? account name
gaim::conversation write conversation style from to text

gaim::conversation provides an API for dealing with conversations. Given that Gaim is an instant messenger program, you'll probably spend a lot of time here.

The command find attempts to find an existing conversation with username name. If the -account option is given, it refines its search to include only conversations on that account.

handle returns the conversations instance handle for the purposes of signal connection. (See gaim::signal connect).

list returns a list of all currently open conversations.

The new subcommand can be used to create a new conversation with a specified user on a specified account if one does not exist, or retrieve the existing conversation if it does. The -chat and -im options specify whether the created conversation should be a chat or a standard IM, respectively.

write is used to write to the specified conversation. The style argument specifies how the text should be printed -- as text coming from the gaim user (style send), being sent to the gaim user (style recv), or as a system message (such as "so-and-so has signed off", style system). From is the name to whom the text should be attributed -- you probably want to check for aliases here, lest you confuse the user. text is the text to print.

gaim::core handle
gaim::core quit

This command exposes functionality provided by the gaim core API.

gaim::core handle returns a handle to the gaim core for signal connection. (See gaim::signal connect).

quit exits gaim cleanly, and should be used in preference to the tcl exit command. (Note that exit has not been removed, however.)

gaim::debug level category message

Equivalent to the C gaim_debug function, this command outputs debugging information to the gaim debug window (or stdout if gaim is invoked with -d|--debug). The valid levels are, in increasing level of severity, -misc, -info, -warning, and, or -error. category is a short (a few characters ... for instance, "tcl" or "tcl plugin") "topic" type name for this message, and message is the text of the message. In the style of Tcl puts (and differing from gaim_debug), no trailing \n is required. (However, embedded newlines may be generated with \n).

gaim::notify ?type? title primary secondary

Also a direct equivalent to a C function, gaim_notify, this command causes gaim to present the provided notification information to the user via some appropriate UI method. The type argument, if present, must be one of -error, -warning, or -info. The following three arguments' absolute meanings may vary with the Gaim UI being used (presently only a Gtk2 UI is available), but title should generally be the title of the window, and primary and secondary text within that window; in the Gtk2 UI, primary is slightly larger than secondary and displayed in a boldface font.

gaim::send_im gc who text

This sends an IM in the fashion of serv_send_im. gc is the GC of the connection on which you wish to send (as returned by most event handlers), who is the nick of the buddy to which you wish to send, and text is the text of the message.

gaim::signal connect instance signal args proc
gaim::signal disconnect instance signal

gaim::signal is a set of subcommands for dealing with gaim signals (known as "events" prior to gaim 0.68).

The connect subcommand registers the procedure proc as a handler for the signal signal on the instance instance. instance should be an instance handle as returned by one of the handle commands from the various parts of gaim. args and @ proc are as in the Tcl proc command; note that the number of arguments in args must match the number of arguments emitted by the signal exactly, although you need not use them all. The procedure proc may be either a simple command or a procedure in curly brackets. Note that only one procedure may be associated with each signal; an attempt to connect a second procedure to the same signal will remove the existing binding and replace it with the new procedure. gaim::signal connect returns 0 on success and 1 on failure.

disconnect removes any existing signal handler for the named signal and instance.

gaim::unload

This unloads the current plugin. Note that preferences will not be updated (yet).

Signals

Check the signals documentation for the meaning of these signals; this is intended to be a list only of their arguments. Signal callbacks will be made in their own namespace, and arguments to those signal callbacks will live in the namespace event underneath that namespace. To briefly illustrate, the signal receiving-im-msg is provided with three arguments; the account on which the IM was received, the screen name of the user sending the IM, and the text of the IM. These arguments live in the variables event::account, event::sender, and event::buffer, respectively. Therefore a callback which notifies the user of an incoming IM containing the word 'shizzle' might look like this:

gaim::signal connect [gaim::conversation handle] receiving-im-msg {
    if {[ string match "*shizzle*" $event::buffer ]} {
        gaim::notify -info "tcl plugin" "Fo' shizzle" \
            "$event::sender is down with the shizzle"
    }
}

Note that for some signals (notably receiving-im-msg, sending-im-msg, and their chat counterparts), changes to the event arguments will change the message itself from Gaim's vantage. For those signals whose return value is meaningful, returning a value from the Tcl event will return that value as it would in C.


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