| 1 | A FEW NOTES ON THE PLUGIN ARCHITECTURE |
| 2 | ====================================== |
| 3 | |
| 4 | The plugin architecture of SquirrelMail is designed to make it |
| 5 | possible to add new features without having to patch SquirrelMail |
| 6 | itself. At the moment the plugin part of SquirrelMail should be |
| 7 | considered "alpha" or "beta" quality code. |
| 8 | |
| 9 | Until the functionality and code is more stable, be prepared for |
| 10 | plugins to suddenly stop working. |
| 11 | |
| 12 | Functionality like password changing, displaying ads and calendars |
| 13 | should be possible to add as plugins. |
| 14 | |
| 15 | |
| 16 | The idea |
| 17 | -------- |
| 18 | |
| 19 | The idea is to be able to run random code at given places in the |
| 20 | SquirrelMail code. This random code should then be able to do whatever |
| 21 | needed to enhance the functionality of SquirrelMail. The places where |
| 22 | code can be executed are called "hooks". |
| 23 | |
| 24 | There are some limitations in what these hooks can do. It is difficult |
| 25 | to use them to change the layout and to change functionality that |
| 26 | already is in SquirrelMail. |
| 27 | |
| 28 | Some way for the plugins to interact with the help subsystem and |
| 29 | translations will be provided. |
| 30 | |
| 31 | |
| 32 | The implementation |
| 33 | ------------------ |
| 34 | |
| 35 | In the main SquirrelMail files the file functions/plugin.php. In |
| 36 | places where hooks are made available they are executed by calling the |
| 37 | function do_hook("hookname"). |
| 38 | |
| 39 | The do_hook traverses the array $squirrelmail_plugin_hooks["hookname"] |
| 40 | and executes all the functions that are named in that array. |
| 41 | |
| 42 | A plugin must reside in a subdirectory in the plugins/ directory. The |
| 43 | name of the subdirectory is considered the name of the plugin. |
| 44 | |
| 45 | To start using a plugin, its name must be added to the $plugins array |
| 46 | in config.php like this: |
| 47 | |
| 48 | $plugins[0] = "plugin_name"; |
| 49 | |
| 50 | When a plugin is registered the file plugins/plugin_name/setup.php is |
| 51 | included and the function squirrelmail_plugin_init_plugin_name is |
| 52 | called with no parameters. |
| 53 | |
| 54 | |
| 55 | Writing plugins |
| 56 | --------------- |
| 57 | |
| 58 | A plugin must consist of at least a file called setup.php. All other |
| 59 | files the plugin consist of should also be in the plugin directory. |
| 60 | |
| 61 | The function squirrelmail_plugin_init_plugin_name is called to |
| 62 | initalize a plugin. This function could look something like this: |
| 63 | |
| 64 | function squirrelmail_plugin_init_demo () { |
| 65 | global $squirrelmail_plugin_hooks; |
| 66 | |
| 67 | $squirrelmail_plugin_hooks["generic_header"]["demo"] = "plugin_demo_header"; |
| 68 | $squirrelmail_plugin_hooks["menuline"]["demo"] = "plugin_demo_menuline"; |
| 69 | } |
| 70 | |
| 71 | Note that the SquirrelMail files assume that all other SquirrelMail |
| 72 | files are available as ../directory/file. This means that if some file |
| 73 | in the plugin directory is requested, it must do a chdir("..") before |
| 74 | including any of the standard SquirrelMail files. |
| 75 | |
| 76 | |
| 77 | List of hooks |
| 78 | ------------- |
| 79 | generic_header functions/page_header.php |
| 80 | menuline functions/page_header.php |
| 81 | compose_button_row src/compose.php |
| 82 | compose_bottom src/compose.php |
| 83 | left_main_before src/left_main.php |
| 84 | left_main_after src/left_main.php |
| 85 | options_save src/options.php (see note on options) |
| 86 | options_link_and_description src/options.php (see note on options) |
| 87 | options_highlight_bottom src/options_highlight.php |
| 88 | options_personal_bottom src/options_personal.php |
| 89 | options_display_bottom src/options_display.php |
| 90 | options_folders_bottom src/options_folders.php |
| 91 | logout src/signout.php |
| 92 | login_before src/webmail.php |
| 93 | login_verified src/webmail.php |
| 94 | loading_prefs src/load_prefs.php |
| 95 | mailbox_index_before functions/mailbox_display.php |
| 96 | mailbox_index_after functions/mailbox_display.php |
| 97 | right_main_after_header src/right_main.php |
| 98 | right_main_bottom src/right_main.php |
| 99 | login_top src/login.php |
| 100 | login_bottom src/login.php |
| 101 | read_body_top src/read_body.php |
| 102 | read_body_bottom src/read_body.php |
| 103 | search_before_form src/search.php |
| 104 | search_after_form src/search.php |
| 105 | search_bottom src/search.php |
| 106 | help_top src/help.php |
| 107 | help_bottom src/help.php |
| 108 | help_chapter src/help.php |
| 109 | abook_html_search_below src/addrbook_search_html.php |
| 110 | addressbook_bottom src/addressbook.php |
| 111 | |
| 112 | Options |
| 113 | ------- |
| 114 | |
| 115 | It is possible to create your own options sections with plugins. There are |
| 116 | three hooks you will need to use. |
| 117 | |
| 118 | 1. options_link_and_description |
| 119 | This creates the link and has a description that are shown on the options |
| 120 | page. This should output HTML that looks like this: |
| 121 | |
| 122 | -----cut here----- |
| 123 | function my_function() { |
| 124 | global $color |
| 125 | ?> |
| 126 | <table width=50% cellpadding=3 cellspacing=0 border=0 align=center> |
| 127 | <tr> |
| 128 | <td bgcolor="<? echo $color[9] ?>"> |
| 129 | <a href="../plugins/YOUR_PLUGIN/YOUR_OPTIONS.php">YOUR OPTIONS NAME</a> |
| 130 | </td> |
| 131 | </tr> |
| 132 | <tr> |
| 133 | <td bgcolor="<? echo $color[0] ?>"> |
| 134 | YOUR DESCRIPTION |
| 135 | </td> |
| 136 | </tr> |
| 137 | </table> |
| 138 | <?php |
| 139 | } |
| 140 | -----cut here----- |
| 141 | |
| 142 | 2. options_save |
| 143 | Here is the code that you need to do to save your options in the |
| 144 | preference files or manipulate whatever data you are trying to change |
| 145 | through the options section. You can look at options.php for details |
| 146 | on how this is to be done. |
| 147 | |
| 148 | 3. loading_prefs (optional) |
| 149 | If you are wanting to save preferences to the preference files, then |
| 150 | you need to do this step as well. Otherwise if you are manipulating |
| 151 | other data, ignore this step. |
| 152 | |
| 153 | You should put the code in here that loads your preferences back |
| 154 | into usable variables. Examples of this can be found in the file |
| 155 | src/load_prefs.php |