doc/plugin.txt

   1 $Id$
   2
   3 It is best if you check out the SquirrelMail development FAQ for more
   4 information.  This document may be obsoleted at some point in the future (or
   5 maybe we'll write a script to get the wiki contents and dump them in here
   6 automatically).
   7
   8 FAQ -> http://www.squirrelmail.org/wiki/wiki.php?DeveloperFAQ
   9 Plugin Hooks -> http://www.squirrelmail.org/wiki/wiki.php?DevelopingPlugins
  10
  11
  12 A FEW NOTES ON THE PLUGIN ARCHITECTURE
  13 ======================================
  14
  15 The plugin architecture of SquirrelMail is designed to make it
  16 possible to add new features without having to patch SquirrelMail
  17 itself. At the moment the plugin part of SquirrelMail should be
  18 considered "alpha" or "beta" quality code.
  19
  20 Until the functionality and code is more stable, be prepared for
  21 plugins to suddenly stop working.
  22
  23 Functionality like password changing, displaying ads and calendars
  24 should be possible to add as plugins.
  25
  26
  27 The idea
  28 --------
  29
  30 The idea is to be able to run random code at given places in the
  31 SquirrelMail code. This random code should then be able to do whatever
  32 needed to enhance the functionality of SquirrelMail. The places where
  33 code can be executed are called "hooks".
  34
  35 There are some limitations in what these hooks can do. It is difficult
  36 to use them to change the layout and to change functionality that
  37 already is in SquirrelMail.
  38
  39 Some way for the plugins to interact with the help subsystem and
  40 translations will be provided.
  41
  42
  43 The implementation
  44 ------------------
  45
  46 In the main SquirrelMail files the file functions/plugin.php. In
  47 places where hooks are made available they are executed by calling the
  48 function do_hook("hookname").
  49
  50 The do_hook traverses the array $squirrelmail_plugin_hooks["hookname"]
  51 and executes all the functions that are named in that array.
  52
  53 A plugin must reside in a subdirectory in the plugins/ directory. The
  54 name of the subdirectory is considered the name of the plugin.
  55
  56 To start using a plugin, its name must be added to the $plugins array
  57 in config.php like this:
  58
  59   $plugins[0] = "plugin_name";
  60
  61 When a plugin is registered the file plugins/plugin_name/setup.php is
  62 included and the function squirrelmail_plugin_init_plugin_name is
  63 called with no parameters.
  64
  65
  66 Writing plugins
  67 ---------------
  68
  69 A plugin must consist of at least a file called setup.php. All other
  70 files the plugin consist of should also be in the plugin directory.
  71
  72 The function squirrelmail_plugin_init_plugin_name is called to
  73 initalize a plugin. This function could look something like this:
  74
  75 function squirrelmail_plugin_init_demo () {
  76   global $squirrelmail_plugin_hooks;
  77
  78   $squirrelmail_plugin_hooks["generic_header"]["demo"] = "plugin_demo_header";
  79   $squirrelmail_plugin_hooks["menuline"]["demo"] = "plugin_demo_menuline";
  80 }
  81
  82 Note that the SquirrelMail files assume that all other SquirrelMail
  83 files are available as ../directory/file. This means that if some file
  84 in the plugin directory is requested, it must do a chdir("..") before
  85 including any of the standard SquirrelMail files.
  86
  87
  88 Hook Data Passed
  89 ----------------
  90 Hooks, when executed, are called with one parameter, an array of data
  91 that is passed to the hook.  The first element in the array is the name
  92 of the hook that is being called.  Any other elements in the array are
  93 dependant on the type of hook that is being called.
  94
  95 Some of the information in the array may be changed.  By default, the
  96 plugins should never change data unless it is documented otherwise.
  97
  98
  99 List of hooks
 100 -------------
 101   generic_header                  functions/page_header.php
 102   menuline                        functions/page_header.php
 103   compose_button_row              src/compose.php
 104   compose_bottom                  src/compose.php
 105   compose_form                    src/compose.php
 106   compose_send                    src/compose.php
 107   left_main_before                src/left_main.php
 108   left_main_after                 src/left_main.php
 109   * options_save                  src/options.php  (see note on options)
 110   * options_link_and_description  src/options.php  (see note on options)
 111   * options_highlight_bottom      src/options_highlight.php
 112   * options_personal_bottom       src/options_personal.php
 113   * options_personal_inside       src/options_personal.php
 114   * options_personal_save         src/options_personal.php
 115   * options_display_bottom        src/options_display.php
 116   * options_display_inside        src/options_display.php
 117   * options_display_save          src/options_display.php
 118   * options_folders_bottom        src/options_folders.php
 119   * options_folders_inside        src/options_folders.php
 120   * options_folders_save          src/options_folders.php
 121   & options_identities_process    src/options_identities.php
 122   & options_identities_top        src/options_identities.php
 123   & options_identities_renumber   src/options_identities.php (multiple places)
 124   & options_identities_table      src/options_identities.php
 125   & options_identities_buttons    src/options_identities.php
 126   logout                          src/signout.php
 127   logout_above_text               src/signout.php
 128   login_before                    src/webmail.php
 129   login_verified                  src/webmail.php
 130   loading_prefs                   src/load_prefs.php
 131   mailbox_index_before            functions/mailbox_display.php
 132   mailbox_index_after             functions/mailbox_display.php
 133   mailbox_form_before             functions/mailbox_display.php
 134   subject_link                    functions/mailbox_display.php
 135   motd                            src/right_main.php
 136   right_main_after_header         src/right_main.php
 137   right_main_bottom               src/right_main.php
 138   login_top                       src/login.php
 139   login_bottom                    src/login.php
 140   html_top                        src/read_body.php
 141   read_body_top                   src/read_body.php
 142   read_body_bottom                src/read_body.php
 143   html_bottom                     src/read_body.php
 144   read_body_header                src/read_body.php
 145   read_body_header_right          src/read_body.php
 146   search_before_form              src/search.php
 147   search_after_form               src/search.php
 148   search_bottom                   src/search.php
 149   help_top                        src/help.php
 150   help_bottom                     src/help.php
 151   help_chapter                    src/help.php
 152   addrbook_html_search_below      src/addrbook_search_html.php
 153   addressbook_bottom              src/addressbook.php
 154   ^ attachment $type0/$type1      functions/mime.php (see note on attachments)
 155
 156
 157 (*) Options
 158 -----------
 159 There are two ways to do options for your plugin.  First, you can incorporate it
 160 into an existing section of the preferences (Display, Personal, or Folders).
 161 The second way, you create your own section that they can choose from and it
 162 displays its own range of options.
 163
 164
 165 First:  Integrating into existing options
 166 -----------------------------------------
 167 There are two hooks you need to use for this one:
 168
 169 1.  options_YOUCHOOSE_inside
 170     This is the code that goes inside the table for the section you choose.  Since
 171     it is going inside an existing table, it must be in this form:
 172     ------cut here-------
 173       <tr>
 174          <td>
 175             OPTION_NAME
 176          </td>
 177          <td>
 178             OPTION_INPUT
 179          </td>
 180       </tr>
 181     ------cut here-------
 182
 183 2.  options_YOUCHOOSE_save
 184     This is the code that saves your preferences into the users' preference
 185     file.  For an example of how to do this, see src/options.php.
 186
 187
 188 Second:  Create your own section
 189 -------------------------------
 190 It is possible to create your own options sections with plugins.  There are
 191 three hooks you will need to use.
 192
 193 1.  options_link_and_description
 194     This creates the link and has a description that are shown on the options
 195     page.  This should output HTML that looks like this.  Make sure to read
 196     the section on outputting your own pages.
 197
 198     -----cut here-----
 199       function my_plugin_name_my_function() {
 200          global $color
 201          ?>
 202          <table width=50% cellpadding=3 cellspacing=0 border=0 align=center>
 203             <tr>
 204                <td bgcolor="<? echo $color[9] ?>">
 205                   <a href="../plugins/YOUR_PLUGIN/YOUR_OPTIONS.php">YOUR OPTIONS NAME</a>
 206                </td>
 207             </tr>
 208             <tr>
 209                <td bgcolor="<? echo $color[0] ?>">
 210                   YOUR DESCRIPTION
 211                </td>
 212             </tr>
 213          </table>
 214          <?php
 215       }
 216     -----cut here-----
 217
 218 2.  options_save
 219     Here is the code that you need to do to save your options in the
 220     preference files or manipulate whatever data you are trying to change
 221     through the options section.  You can look at options.php for details
 222     on how this is to be done.
 223
 224 3.  loading_prefs (optional)
 225     If you are wanting to save preferences to the preference files, then
 226     you need to do this step as well.  Otherwise if you are manipulating
 227     other data, ignore this step.
 228
 229     You should put the code in here that loads your preferences back
 230     into usable variables.  Examples of this can be found in the file
 231     src/load_prefs.php
 232
 233
 234 (&) Identity Hooks
 235 ------------------
 236 Some hooks are passed special information in the array of arguments.  See
 237 the SpamCop plugin for how to use them.
 238
 239 options_identities_process
 240    [0] = Hook's name
 241    [1] = Should I run the SaveUpdateFunction() (alterable)
 242
 243 options_identities_renumber
 244    [0] = Hook's name
 245    [1] = Renumber it from ('default' or 1 through # idents - 1)
 246    [2] = Renumber it to (same thing)
 247
 248 options_identities_table
 249    [0] = Hook's name
 250    [1] = Color of table (use it like   <tr<?PHP echo $Info[1]?>>   in your
 251          plugin)
 252    [2] = Is this an empty section?
 253    [3] = What is the 'post' value?
 254
 255 options_identities_buttons
 256    [0] = Hook's name
 257    [1] = Is this an empty section (the one at the end of the list)?
 258    [2] = What is the 'post' value?
 259
 260
 261 (^) Attachment Hooks
 262 --------------------
 263 When a message has attachments, this hook is called with the MIME types.  For
 264 instance, a .zip file hook is "attachment application/x-zip".  The hook should
 265 probably show a link to do a specific action, such as "Verify" or "View" for a
 266 .zip file.
 267
 268 This is a breakdown of the data passed in the array to the hook that is called:
 269
 270   [0] = Hook's name ('attachment text/plain')
 271   [1] = Array of links of actions (more below) (Alterable)
 272   [2] = Used for returning to mail message (startMessage)
 273   [3] = Used for finding message to display (id)
 274   [4] = Mailbox name, urlencode()'d (urlMailbox)
 275   [5] = Entity ID inside mail message (ent)
 276   [6] = Default URL to go to when filename is clicked on (Alterable)
 277   [7] = Filename that is displayed for the attachment
 278   [8] = Sent if message was found from a search (where)
 279   [9] = Sent if message was found from a search (what)
 280
 281 To set up links for actions, you assign them like this:
 282
 283   $Args[1]['your_plugin_name']['href'] = 'URL to link to';
 284   $Args[1]['your_plugin_name']['text'] = 'What to display';
 285
 286
 287 Outputting Your Own Pages
 288 -------------------------
 289
 290 Often, when you want to provide your own customized options screen or create
 291 another web page instead of just using standard hooks, you will be creating
 292 your own .php files.  An example of this is the attachment_common plugin's
 293 image.php file.
 294
 295 To make sure that security is maintained and standards are followed, the top
 296 of your PHP script should look very similar to this:
 297
 298   <?PHP
 299     /* This is my php file.
 300      * description goes here.
 301      */
 302
 303     chdir('..');
 304     include('../src/validate.php');
 305
 306 The validate.php script will include internationalization support,
 307 config.php variables, strings.php functions, and also authenticate that the
 308 user is truly logged in.  Validate.php also calls stripslashes() on incoming
 309 data (if gpc_magic_quotes() is on).  You should never need to worry about
 310 that stuff again.  As a warning, this has only really been ironed out in
 311 1.1.1.  If you create/modify a plugin to follow these rules, you must
 312 mention that it requires SquirrelMail 1.1.1 or later.
 313
 314 After that, if you need further functions, just use
 315
 316   include('../functions/filename.php');
 317
 318 in your script.  Since 1.0.5, it was no longer necessary (nor recommended)
 319 to use the "if (! isset($filename_php))" syntax.