| 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 | Hook Data Passed |
| 78 | ---------------- |
| 79 | Hooks, when executed, are called with one parameter, an array of data |
| 80 | that is passed to the hook. The first element in the array is the name |
| 81 | of the hook that is being called. Any other elements in the array are |
| 82 | dependant on the type of hook that is being called. |
| 83 | |
| 84 | Some of the information in the array may be changed. By default, the |
| 85 | plugins should never change data unless it is documented otherwise. |
| 86 | |
| 87 | |
| 88 | List of hooks |
| 89 | ------------- |
| 90 | generic_header functions/page_header.php |
| 91 | menuline functions/page_header.php |
| 92 | compose_button_row src/compose.php |
| 93 | compose_bottom src/compose.php |
| 94 | compose_form src/compose.php |
| 95 | left_main_before src/left_main.php |
| 96 | left_main_after src/left_main.php |
| 97 | * options_save src/options.php (see note on options) |
| 98 | * options_link_and_description src/options.php (see note on options) |
| 99 | * options_highlight_bottom src/options_highlight.php |
| 100 | * options_personal_bottom src/options_personal.php |
| 101 | * options_personal_inside src/options_personal.php |
| 102 | * options_personal_save src/options_personal.php |
| 103 | * options_display_bottom src/options_display.php |
| 104 | * options_display_inside src/options_display.php |
| 105 | * options_display_save src/options_display.php |
| 106 | * options_folders_bottom src/options_folders.php |
| 107 | * options_folders_inside src/options_folders.php |
| 108 | * options_folders_save src/options_folders.php |
| 109 | logout src/signout.php |
| 110 | login_before src/webmail.php |
| 111 | login_verified src/webmail.php |
| 112 | loading_prefs src/load_prefs.php |
| 113 | mailbox_index_before functions/mailbox_display.php |
| 114 | mailbox_index_after functions/mailbox_display.php |
| 115 | mailbox_form_before functions/mailbox_display.php |
| 116 | right_main_after_header src/right_main.php |
| 117 | right_main_bottom src/right_main.php |
| 118 | login_top src/login.php |
| 119 | login_bottom src/login.php |
| 120 | html_top src/read_body.php |
| 121 | read_body_top src/read_body.php |
| 122 | read_body_bottom src/read_body.php |
| 123 | html_bottom src/read_body.php |
| 124 | read_body_header src/read_body.php |
| 125 | search_before_form src/search.php |
| 126 | search_after_form src/search.php |
| 127 | search_bottom src/search.php |
| 128 | help_top src/help.php |
| 129 | help_bottom src/help.php |
| 130 | help_chapter src/help.php |
| 131 | addrbook_html_search_below src/addrbook_search_html.php |
| 132 | addressbook_bottom src/addressbook.php |
| 133 | ^ attachment $type0/$type1 functions/mime.php (see note on attachments) |
| 134 | |
| 135 | |
| 136 | (*) Options |
| 137 | ----------- |
| 138 | There are two ways to do options for your plugin. First, you can incorporate it |
| 139 | into an existing section of the preferences (Display, Personal, or Folders). |
| 140 | The second way, you create your own section that they can choose from and it |
| 141 | displays its own range of options. |
| 142 | |
| 143 | |
| 144 | First: Integrating into existing options |
| 145 | ----------------------------------------- |
| 146 | There are two hooks you need to use for this one: |
| 147 | |
| 148 | 1. options_YOUCHOOSE_inside |
| 149 | This is the code that goes inside the table for the section you choose. Since |
| 150 | it is going inside an existing table, it must be in this form: |
| 151 | ------cut here------- |
| 152 | <tr> |
| 153 | <td> |
| 154 | OPTION_NAME |
| 155 | </td> |
| 156 | <td> |
| 157 | OPTION_INPUT |
| 158 | </td> |
| 159 | </tr> |
| 160 | ------cut here------- |
| 161 | |
| 162 | 2. options_YOUCHOOSE_save |
| 163 | This is the code that saves your preferences into the users' preference |
| 164 | file. For an example of how to do this, see src/options.php. |
| 165 | |
| 166 | |
| 167 | Second: Create your own section |
| 168 | ------------------------------- |
| 169 | It is possible to create your own options sections with plugins. There are |
| 170 | three hooks you will need to use. |
| 171 | |
| 172 | 1. options_link_and_description |
| 173 | This creates the link and has a description that are shown on the options |
| 174 | page. This should output HTML that looks like this: |
| 175 | |
| 176 | -----cut here----- |
| 177 | function my_function() { |
| 178 | global $color |
| 179 | ?> |
| 180 | <table width=50% cellpadding=3 cellspacing=0 border=0 align=center> |
| 181 | <tr> |
| 182 | <td bgcolor="<? echo $color[9] ?>"> |
| 183 | <a href="../plugins/YOUR_PLUGIN/YOUR_OPTIONS.php">YOUR OPTIONS NAME</a> |
| 184 | </td> |
| 185 | </tr> |
| 186 | <tr> |
| 187 | <td bgcolor="<? echo $color[0] ?>"> |
| 188 | YOUR DESCRIPTION |
| 189 | </td> |
| 190 | </tr> |
| 191 | </table> |
| 192 | <?php |
| 193 | } |
| 194 | -----cut here----- |
| 195 | |
| 196 | 2. options_save |
| 197 | Here is the code that you need to do to save your options in the |
| 198 | preference files or manipulate whatever data you are trying to change |
| 199 | through the options section. You can look at options.php for details |
| 200 | on how this is to be done. |
| 201 | |
| 202 | 3. loading_prefs (optional) |
| 203 | If you are wanting to save preferences to the preference files, then |
| 204 | you need to do this step as well. Otherwise if you are manipulating |
| 205 | other data, ignore this step. |
| 206 | |
| 207 | You should put the code in here that loads your preferences back |
| 208 | into usable variables. Examples of this can be found in the file |
| 209 | src/load_prefs.php |
| 210 | |
| 211 | |
| 212 | (^) Attachment Hooks |
| 213 | -------------------- |
| 214 | When a message has attachments, this hook is called with the MIME types. For |
| 215 | instance, a .zip file hook is "attachment application/x-zip". The hook should |
| 216 | probably show a link to do a specific action, such as "Verify" or "View" for a |
| 217 | .zip file. |
| 218 | |
| 219 | This is a breakdown of the data passed in the array to the hook that is called: |
| 220 | |
| 221 | [0] = Hook's name ('attachment text/plain') |
| 222 | [1] = Array of links of actions (more below) (Alterable) |
| 223 | [2] = Used for returning to mail message (startMessage) |
| 224 | [3] = Used for finding message to display (id) |
| 225 | [4] = Mailbox name, urlencode()'d (urlMailbox) |
| 226 | [5] = Entity ID inside mail message (ent) |
| 227 | [6] = Default URL to go to when filename is clicked on (Alterable) |
| 228 | [7] = Filename that is displayed for the attachment |
| 229 | [8] = Sent if message was found from a search (where) |
| 230 | [9] = Sent if message was found from a search (what) |
| 231 | |
| 232 | To set up links for actions, you assign them like this: |
| 233 | |
| 234 | $Args[1]['your_plugin_name']['href'] = 'URL to link to'; |
| 235 | $Args[1]['your_plugin_name']['text'] = 'What to display'; |
| 236 | |