squirrelmail/doc/plugin.txt
2002-06-10 18:22:40 +00:00

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It is best if you check out the SquirrelMail development FAQ for more
information. This document may be obsoleted at some point in the future (or
maybe we'll write a script to get the wiki contents and dump them in here
automatically).
FAQ -> http://www.squirrelmail.org/wiki/wiki.php?DeveloperFAQ
Plugin Hooks -> http://www.squirrelmail.org/wiki/wiki.php?DevelopingPlugins
A FEW NOTES ON THE PLUGIN ARCHITECTURE
======================================
The plugin architecture of SquirrelMail is designed to make it possible to
add new features without having to patch SquirrelMail itself. Functionality
like password changing, displaying ads and calendars should be possible to
add as plugins.
The idea
--------
The idea is to be able to run random code at given places in the
SquirrelMail code. This random code should then be able to do whatever
needed to enhance the functionality of SquirrelMail. The places where
code can be executed are called "hooks".
There are some limitations in what these hooks can do. It is difficult
to use them to change the layout and to change functionality that
already is in SquirrelMail.
Some way for the plugins to interact with the help subsystem and
translations will be provided.
The implementation
------------------
In the main SquirrelMail files the file functions/plugin.php. In
places where hooks are made available they are executed by calling the
function do_hook('hookname').
The do_hook traverses the array $squirrelmail_plugin_hooks['hookname']
and executes all the functions that are named in that array.
A plugin must reside in a subdirectory in the plugins/ directory. The
name of the subdirectory is considered the name of the plugin.
To start using a plugin, its name must be added to the $plugins array
in config.php like this:
$plugins[0] = 'plugin_name';
When a plugin is registered the file plugins/plugin_name/setup.php is
included and the function squirrelmail_plugin_init_plugin_name is
called with no parameters.
Writing plugins
---------------
A plugin must consist of at least a file called setup.php. All other
files the plugin consist of should also be in the plugin directory.
The function squirrelmail_plugin_init_plugin_name is called to
initalize a plugin. This function could look something like this:
function squirrelmail_plugin_init_demo () {
global $squirrelmail_plugin_hooks;
$squirrelmail_plugin_hooks['generic_header']['demo'] = 'plugin_demo_header';
$squirrelmail_plugin_hooks['menuline']['demo'] = 'plugin_demo_menuline';
}
Note that the SquirrelMail files assume that all other SquirrelMail
files are available as ../directory/file. This means that if some file
in the plugin directory is requested, it must do a chdir('..') before
including any of the standard SquirrelMail files.
Hook Data Passed
----------------
Hooks, when executed, are called with one parameter, an array of data
that is passed to the hook. The first element in the array is the name
of the hook that is being called. Any other elements in the array are
dependant on the type of hook that is being called.
Some of the information in the array may be changed. By default, the
plugins should never change data unless it is documented otherwise.
List of hooks
-------------
generic_header functions/page_header.php
menuline functions/page_header.php
compose_button_row src/compose.php
compose_bottom src/compose.php
compose_form src/compose.php
compose_send src/compose.php
left_main_before src/left_main.php
left_main_after src/left_main.php
* options_save src/options.php (see note on options)
* options_link_and_description src/options.php (see note on options)
* options_highlight_bottom src/options_highlight.php
* options_personal_bottom src/options_personal.php
* options_personal_inside src/options_personal.php
* options_personal_save src/options_personal.php
* options_display_bottom src/options_display.php
* options_display_inside src/options_display.php
* options_display_save src/options_display.php
* options_folders_bottom src/options_folders.php
* options_folders_inside src/options_folders.php
* options_folders_save src/options_folders.php
& options_identities_process src/options_identities.php
& options_identities_top src/options_identities.php
& options_identities_renumber src/options_identities.php (multiple places)
& options_identities_table src/options_identities.php
& options_identities_buttons src/options_identities.php
logout src/signout.php
logout_above_text src/signout.php
login_before src/webmail.php
login_verified src/webmail.php
loading_prefs src/load_prefs.php
mailbox_index_before functions/mailbox_display.php
mailbox_index_after functions/mailbox_display.php
mailbox_form_before functions/mailbox_display.php
subject_link functions/mailbox_display.php
motd src/right_main.php
right_main_after_header src/right_main.php
right_main_bottom src/right_main.php
login_top src/login.php
login_bottom src/login.php
html_top src/read_body.php
read_body_top src/read_body.php
read_body_bottom src/read_body.php
html_bottom src/read_body.php
read_body_header src/read_body.php
read_body_header_right src/read_body.php
read_body_after_from src/read_body.php
search_before_form src/search.php
search_after_form src/search.php
search_bottom src/search.php
help_top src/help.php
help_bottom src/help.php
help_chapter src/help.php
addrbook_html_search_below src/addrbook_search_html.php
addressbook_bottom src/addressbook.php
^ attachment $type0/$type1 functions/mime.php (see note on attachments)
(*) Options
-----------
There are two ways to do options for your plugin. First, you can incorporate it
into an existing section of the preferences (Display, Personal, or Folders).
The second way, you create your own section that they can choose from and it
displays its own range of options.
First: Integrating into existing options
-----------------------------------------
There are two hooks you need to use for this one:
1. options_YOUCHOOSE_inside
This is the code that goes inside the table for the section you choose. Since
it is going inside an existing table, it must be in this form:
------cut here-------
<tr>
<td>
OPTION_NAME
</td>
<td>
OPTION_INPUT
</td>
</tr>
------cut here-------
2. options_YOUCHOOSE_save
This is the code that saves your preferences into the users' preference
file. For an example of how to do this, see src/options.php.
Second: Create your own section
-------------------------------
It is possible to create your own options sections with plugins. There are
three hooks you will need to use.
1. options_link_and_description
This creates the link and has a description that is shown on the options
page. This should output HTML that looks like this. Make sure to read
the section on outputing your own pages.
-----cut here-----
function my_plugin_name_my_function() {
global $color
?>
<table width=50% cellpadding=3 cellspacing=0 border=0 align=center>
<tr>
<td bgcolor="<?php echo $color[9] ?>">
<a href="../plugins/YOUR_PLUGIN/YOUR_OPTIONS.php">YOUR OPTIONS NAME</a>
</td>
</tr>
<tr>
<td bgcolor="<?php echo $color[0] ?>">
YOUR DESCRIPTION
</td>
</tr>
</table>
<?php
}
-----cut here-----
2. options_save
Here is the code that you need to do to save your options in the
preference files or manipulate whatever data you are trying to change
through the options section. You can look at options.php for details
on how this is to be done.
3. loading_prefs (optional)
If you are wanting to save preferences to the preference files, then
you need to do this step as well. Otherwise if you are manipulating
other data, ignore this step.
You should put the code in here that loads your preferences back
into usable variables. Examples of this can be found in the file
src/load_prefs.php
(&) Identity Hooks
------------------
Some hooks are passed special information in the array of arguments. See
the SpamCop plugin for how to use them.
options_identities_process
[0] = Hook's name
[1] = Should I run the SaveUpdateFunction() (alterable)
options_identities_renumber
[0] = Hook's name
[1] = Renumber it from ('default' or 1 through # idents - 1)
[2] = Renumber it to (same thing)
options_identities_table
[0] = Hook's name
[1] = Color of table (use it like <tr<?PHP echo $Info[1]?>> in your
plugin)
[2] = Is this an empty section?
[3] = What is the 'post' value?
options_identities_buttons
[0] = Hook's name
[1] = Is this an empty section (the one at the end of the list)?
[2] = What is the 'post' value?
(^) Attachment Hooks
--------------------
When a message has attachments, this hook is called with the MIME types. For
instance, a .zip file hook is "attachment application/x-zip". The hook should
probably show a link to do a specific action, such as "Verify" or "View" for a
.zip file.
This is a breakdown of the data passed in the array to the hook that is called:
[0] = Hook's name ('attachment text/plain')
[1] = Array of links of actions (more below) (Alterable)
[2] = Used for returning to mail message (startMessage)
[3] = Used for finding message to display (id)
[4] = Mailbox name, urlencode()'d (urlMailbox)
[5] = Entity ID inside mail message (ent)
[6] = Default URL to go to when filename is clicked on (Alterable)
[7] = Filename that is displayed for the attachment
[8] = Sent if message was found from a search (where)
[9] = Sent if message was found from a search (what)
To set up links for actions, you assign them like this:
$Args[1]['your_plugin_name']['href'] = 'URL to link to';
$Args[1]['your_plugin_name']['text'] = 'What to display';
It's also possible to specify a hook as "attachment type0/*",
for example "attachment text/*". This hook will be executed whenever there's
no more specific rule available for that type.
Outputting Your Own Pages
-------------------------
Often, when you want to provide your own customized options screen or create
another web page instead of just using standard hooks, you will be creating
your own .php files. An example of this is the attachment_common plugin's
image.php file.
To make sure that security is maintained and standards are followed, the top
of your PHP script should look very similar to this:
<?PHP
/* This is my php file.
* description goes here.
*/
chdir('..');
include('../src/validate.php');
The validate.php script will include internationalization support,
config.php variables, strings.php functions, and also authenticate that the
user is truly logged in. validate.php also calls stripslashes() on incoming
data (if gpc_magic_quotes() is on). You should never need to worry about
that stuff again. As a warning, this has only really been ironed out in
1.1.1. If you create/modify a plugin to follow these rules, you must
mention that it requires SquirrelMail 1.1.1 or later.
After that, if you need further functions, just use
include('../functions/filename.php');
in your script. Since 1.0.5, it was no longer necessary (nor recommended)
to use the "if (! isset($filename_php))" syntax.