3 In addition to this document, please check out the SquirrelMail
4 development FAQ for more information. Also, help writing plugins
5 is easily obtained by posting to the squirrelmail-plugins mailing
6 list. (See details about mailing lists on the website)
8 FAQ -> http://www.squirrelmail.org/wiki/wiki.php?DeveloperFAQ
10 http://www.squirrelmail.org/wiki/wiki.php?DevelopingPlugins
13 A FEW NOTES ON THE PLUGIN ARCHITECTURE
14 ======================================
16 The plugin architecture of SquirrelMail is designed to make it possible
17 to add new features without having to patch SquirrelMail itself.
18 Functionality like password changing, displaying ads and calendars should
19 be possible to add as plugins.
25 The idea is to be able to run random code at given places in the
26 SquirrelMail code. This random code should then be able to do whatever
27 needed to enhance the functionality of SquirrelMail. The places where
28 code can be executed are called "hooks".
30 There are some limitations in what these hooks can do. It is difficult
31 to use them to change the layout and to change functionality that
32 already is in SquirrelMail.
34 Some way for the plugins to interact with the help subsystem and
35 translations will be provided.
41 The plugin jumping off point in the main SquirrelMail code is in the
42 file functions/plugin.php. In places where hooks are made available,
43 they are executed by calling the function do_hook('hookname'). The
44 do_hook function then traverses the array
45 $squirrelmail_plugin_hooks['hookname'] and executes all the functions
46 that are named in that array. Those functions are placed there when
47 plugins register themselves with SquirrelMail as discussed below. A
48 plugin may add its own internal functions to this array under any
49 hook name provided by the SquirrelMail developers.
51 A plugin must reside in a subdirectory in the plugins/ directory. The
52 name of the subdirectory is considered to be the name of the plugin.
53 (The plugin will not function correctly if this is not the case.)
55 To start using a plugin, its name must be added to the $plugins array
56 in config.php like this:
58 $plugins[0] = 'plugin_name';
60 When a plugin is registered, the file plugins/plugin_name/setup.php is
61 included and the function squirrelmail_plugin_init_plugin_name() is
62 called with no parameters. That function is where the plugin may
63 register itself against any hooks it wishes to take advantage of.
69 All plugins must contain a file called setup.php and must include a
70 function called squirrelmail_plugin_init_plugin_name() therein. Since
71 including numerous plugins can slow SquirrelMail performance
72 considerably, the setup.php file should contain little else. Any
73 functions that are registered against plugin hooks should do little
74 more than call another function in a different file.
76 Any other files used by the plugin should also be placed in the
77 plugin directory (or subdirectory thereof) and should contain the
78 bulk of the plugin logic.
80 The function squirrelmail_plugin_init_plugin_name() is called to
81 initalize a plugin. This function could look something like this (if
82 the plugin was named "demo" and resided in the directory plugins/demo/):
84 function squirrelmail_plugin_init_demo ()
86 global $squirrelmail_plugin_hooks;
88 $squirrelmail_plugin_hooks['generic_header']['demo'] = 'plugin_demo_header';
89 $squirrelmail_plugin_hooks['menuline']['demo'] = 'plugin_demo_menuline';
92 Please note that as of SquirrelMail 1.5.0, this function will no longer
93 be called at run time and will instead be called only once at configure-
94 time. Thus, the inclusion of any dynamic code (anything except hook
95 registration) here is strongly discouraged.
97 In this example, the "demo" plugin should also have two other functions
98 in its setup.php file called plugin_demo_header() and plugin_demo_menuline().
99 The first of these might look something like this:
101 function plugin_demo_header()
103 include_once(SM_PATH . 'plugins/demo/functions.php');
104 plugin_demo_header_do();
107 The function called plugin_demo_header_do() would be in the file called
108 functions.php in the demo plugin directory and would contain the plugin's
109 core logic for the "generic_header" hook.
112 Including Other Files
113 ---------------------
115 A plugin may need to reference functionality provided in other
116 files, and therefore need to include those files. Most of the
117 core SquirrelMail functions are already available to your plugin
118 unless it has any files that are requested directly by the client
119 browser (custom options page, etc.). In this case, you'll need
120 to make sure you include the files you need (see below).
122 Note that as of SquirrelMail 1.4.0, all files are accessed using a
123 constant called SM_PATH that always contains the relative path to
124 the main SquirrelMail directory. This constant is always available
125 for you to use when including other files from the SquirrelMail core,
126 your own plugin, or other plugins, should the need arise. If any of
127 your plugin files are requested directly from the client browser,
128 you will need to define this constant before you do anything else:
130 define('SM_PATH', '../../');
132 Files are included like this:
134 include_once(SM_PATH . 'include/validate.php');
136 When including files, please make sure to use the include_once() function
137 and NOT include(), require(), or require_once(), since these all are much
138 less efficient than include_once() and can have a cumulative effect on
139 SquirrelMail performance.
141 The files that you may need to include in a plugin will vary greatly
142 depending upon what the plugin is designed to do. For files that are
143 requested directly by the client browser, we strongly recommend that
144 you include the file include/validate.php, since it will set up the
145 SquirrelMail environment automatically. It will ensure the the user
146 has been authenticated and is currently logged in, load all user
147 preferences, include internationalization support, call stripslashes()
148 on all incoming data (if magic_quotes_gpc is on), and initialize and
149 include all other basic SquirrelMail resources and functions. You may
150 see other plugins that directly include other SquirrelMail files, but
151 that is no longer necessary and is a hold-over from older SquirrelMail
154 List of files, that are included by include/validate.php (If SquirrelMail
155 version is not listed, files are included from v.1.3.2.):
156 1. class/mime.class.php
157 1.1. class/mime/Rfc822Header.class.php
158 1.2. class/mime/MessageHeader.class.php
159 1.3. class/mime/AddressStructure.class.php
160 1.4. class/mime/Message.class.php
161 1.5. class/mime/SMimeMessage.class.php
162 1.6. class/mime/Disposition.class.php
163 1.7. class/mime/Language.class.php
164 1.8. class/mime/ContentType.class.php
165 2. functions/global.php
166 3. functions/strings.php
168 4.1. config/config_local.php (from 1.4.0rc1)
169 5. functions/i18n.php
170 5.1. functions/global.php (from 1.4.0)
171 6. functions/auth.php
172 7. include/load_prefs.php
173 7.1. include/validate.php
174 7.2. functions/prefs.php
175 7.3. functions/plugin.php
176 7.3.1. functions/global.php (from 1.4.0 and 1.5.0)
177 7.3.2. functions/prefs.php (from 1.5.1)
178 7.4. functions/constants.php
179 7.5. do_hook('loading_prefs')
180 8. functions/page_header.php
181 8.1. functions/strings.php
182 8.2. functions/html.php
183 8.3. functions/imap_mailbox.php
184 8.3.1. functions/imap_utf7_local.php
185 8.4. functions/global.php
186 9. functions/prefs.php
187 9.1. functions/global.php
188 9.2. $prefs_backend (from 1.4.3rc1 and 1.5.0)
189 functions/db_prefs.php
190 functions/file_prefs.php
192 Hook Types: Parameters and Return Values
193 -----------------------------------------
195 Hooks, when executed, are called with differing parameters and may or may
196 not take return values, all depending on the type of hook being called and
197 the context in which it is being used. On the source side (where the hook
198 call originates), all hooks have at least one parameter, which is the
199 name of the hook. After that, things get complicated.
203 Most hook calls don't pass any data and don't ask for anything back.
204 These always use the do_hook call. A limited number of do_hook calls do
205 pass some extra parameters, in which case your plugin may modify the
206 given data if you do so by reference. It is not necessary to return
207 anything from your function in such a case; modifying the parameter
208 data by reference is what does the job (although the hook call itself
209 (in the source) must grab the return value for this to work). Note
210 that in this case, the parameter to your hook function will be an array,
211 the first element simply being the hook name, followed by any other
212 parameters that may have been included in the actual hook call in the
213 source. Modify parameters with care!
217 This hook type was intended to be the main hook type used when the
218 source needs to get something back from your plugin. It is somewhat
219 limited in that it will only use the value returned from the LAST
220 plugin registered against the hook. The source for this hook might
221 use the return value for internal purposes, or might expect you to
222 provide text or HTML to be sent to the client browser (you'll have to
223 look at its use in context to understand how you should return values
224 here). The parameters that your hook function gets will be anything
225 you see AFTER the hook name in the actual hook call in the source.
226 These cannot be changed in the same way that the do_hook parameters
231 This is a newer hook type meant to address the shortcomings of
232 do_hook_function; specifically in that it uses the return values of
233 all plugins registered against the hook. In order to do so, the
234 return value is assumed to be a string, which is just piled on top
235 of whatever it got from the other plugins working on the same hook.
236 Again, you'll have to inspect the source code to see how such data
237 is put to use, but most of the time, it is used to create a string
238 of HTML to be inserted into the output page. The parameters that
239 your hook function will get are the same as for the do_hook_function;
240 they are anything AFTER the hook name in the actual hook call in the
243 boolean_hook_function
244 ---------------------
245 The newest of the SquirrelMail hooks, this type is used to let all
246 plugins registered against the hook to "vote" for some action. What
247 that action is is entirely dependent on how the hook is used in the
248 source (look for yourself). Plugins make their "vote" by returning
249 TRUE or FALSE. This hook may be configured to "tally votes" in one
250 of three ways. This configuration is done with the third parameter
251 in the hook call in the source:
252 > 0 -- Any one or more TRUEs will override any FALSEs
253 < 0 -- Any one or more FALSEs will override any TRUEs
254 = 0 -- Majority wins. Ties are broken in this case with
255 the last parameter in the hook call in the source.
256 Your hook function will get the second paramter in the hook call in
257 the source as its parameter (this might be an array if multiple values
260 See below for further discussion of special hook types and the values
266 This is a list of all hooks currently available in SquirrelMail, ordered
267 by file. Note that this list is accurate as of June 17, 2003 (should be
268 close to what is contained in release 1.4.1, plus or minus a hook or two),
269 but may be out of date soon thereafter. You never know. ;-)
271 Hook Name Found In Called With(#)
272 --------- -------- --------------
273 abook_init functions/addressbook.php do_hook
274 abook_add_class functions/addressbook.php do_hook
275 loading_constants functions/constants.php do_hook
276 logout_error functions/display_messages.php do_hook
277 error_box functions/display_messages.php concat_hook
278 get_pref_override functions/file_prefs.php hook_func
279 get_pref functions/file_prefs.php hook_func
280 special_mailbox functions/imap_mailbox.php hook_func
281 % rename_or_delete_folder functions/imap_mailbox.php hook_func
282 mailbox_index_before functions/mailbox_display.php do_hook
283 mailbox_form_before functions/mailbox_display.php do_hook
284 mailbox_index_after functions/mailbox_display.php do_hook
285 check_handleAsSent_result functions/mailbox_display.php do_hook
286 subject_link functions/mailbox_display.php concat_hook
287 mailbox_display_buttons functions/mailbox_display.php do_hook
288 mailbox_display_button_action functions/mailbox_display.php hook_func
289 message_body functions/mime.php do_hook
290 ^ attachment $type0/$type1 functions/mime.php do_hook
291 attachments_bottom functions/mime.php hook_func
292 decode_body functions/mime.php hook_func
293 generic_header functions/page_header.php do_hook
294 menuline functions/page_header.php do_hook
295 internal_link functions/page_header.php hook_func
296 loading_prefs include/load_prefs.php do_hook
297 addrbook_html_search_below src/addrbook_search_html.php do_hook
298 addressbook_bottom src/addressbook.php do_hook
299 compose_form src/compose.php do_hook
300 compose_bottom src/compose.php do_hook
301 compose_button_row src/compose.php do_hook
302 compose_send src/compose.php do_hook
303 folders_bottom src/folders.php do_hook
304 help_top src/help.php do_hook
305 help_chapter src/help.php do_hook
306 help_bottom src/help.php do_hook
307 left_main_after_each_folder src/left_main.php concat_hook
308 left_main_before src/left_main.php do_hook
309 left_main_after src/left_main.php do_hook
310 login_cookie src/login.php do_hook
311 login_top src/login.php do_hook
312 login_form src/login.php do_hook
313 login_bottom src/login.php do_hook
314 * optpage_set_loadinfo src/options.php do_hook
315 * optpage_loadhook_personal src/options.php do_hook
316 * optpage_loadhook_display src/options.php do_hook
317 * optpage_loadhook_highlight src/options.php do_hook
318 * optpage_loadhook_folder src/options.php do_hook
319 * optpage_loadhook_order src/options.php do_hook
320 * options_personal_save src/options.php do_hook
321 * options_display_save src/options.php do_hook
322 * options_folder_save src/options.php do_hook
323 * options_save src/options.php do_hook
324 * optpage_register_block src/options.php do_hook
325 * options_link_and_description src/options.php do_hook
326 * options_personal_inside src/options.php do_hook
327 * options_display_inside src/options.php do_hook
328 * options_highlight_inside src/options.php do_hook
329 * options_folder_inside src/options.php do_hook
330 * options_order_inside src/options.php do_hook
331 * options_personal_bottom src/options.php do_hook
332 * options_display_bottom src/options.php do_hook
333 * options_highlight_bottom src/options.php do_hook
334 * options_folder_bottom src/options.php do_hook
335 * options_order_bottom src/options.php do_hook
336 * options_highlight_bottom src/options_highlight.php do_hook
337 & options_identities_process src/options_identities.php do_hook
338 & options_identities_top src/options_identities.php do_hook
339 &% options_identities_renumber src/options_identities.php do_hook
340 & options_identities_table src/options_identities.php concat_hook
341 & options_identities_buttons src/options_identities.php concat_hook
342 message_body src/printer_friendly_bottom.php do_hook
343 read_body_header src/read_body.php do_hook
344 read_body_menu_top src/read_body.php hook_func
345 read_body_menu_bottom src/read_body.php do_hook
346 read_body_header_right src/read_body.php do_hook
347 read_body_top src/read_body.php do_hook
348 read_body_bottom src/read_body.php do_hook
349 login_before src/redirect.php do_hook
350 login_verified src/redirect.php do_hook
351 generic_header src/right_main.php do_hook
352 right_main_after_header src/right_main.php do_hook
353 right_main_bottom src/right_main.php do_hook
354 search_before_form src/search.php do_hook
355 search_after_form src/search.php do_hook
356 search_bottom src/search.php do_hook
357 logout src/signout.php do_hook
358 webmail_top src/webmail.php do_hook
359 webmail_bottom src/webmail.php concat_hook
360 logout_above_text src/signout.php concat_hook
361 O info_bottom plugins/info/options.php do_hook
363 % = This hook is used in multiple places in the given file
364 # = Called with hook type (see below)
365 & = Special identity hooks (see below)
366 ^ = Special attachments hook (see below)
367 * = Special options hooks (see below)
368 O = optional hook used by plugin
373 Each hook is called using the hook type specified in the list above:
375 hook_func do_hook_function()
376 concat_hook concat_hook_function()
381 This set of hooks is passed special information in the array of arguments:
383 options_identities_process
385 This hook is called at the top of the Identities page, which is
386 most useful when the user has changed any identity settings - this
387 is where you'll want to save any custom information you are keeping
388 for each identity or catch any custom submit buttons that you may
389 have added to the identities page. The arguments to this hook are:
391 [0] = hook name (always "options_identities_process")
392 [1] = should I run the SaveUpdateFunction() (alterable)
394 Obviously, set the second array element to 1/true if you want to
395 trigger SaveUpdateFunction() after the hook is finished - by default,
396 it will not be called.
398 options_identities_renumber
400 This hook is called when one of the identities is being renumbered,
401 such as if the user had three identities and deletes the second -
402 this hook would be called with an array that looks like this:
403 ('options_identities_renumber', 2, 1). The arguments to this hook
406 [0] = hook name (always "options_identities_renumber")
407 [1] = being renumbered from ('default' or 1 through (# idents) - 1)
408 [2] = being renumbered to ('default' or 1 through (# idents) - 1)
410 options_identities_table
412 This hook allows you to insert additional rows into the table that
413 holds each identity. The arguments to this hook are:
415 [0] = color of table (use it like this in your plugin:
416 <tr bgcolor="<?php echo $info[1]; ?>">
417 [1] = is this an empty section (the one at the end of the list)?
418 [2] = what is the 'post' value? (ident # or empty string if default)
420 You need to return any HTML you would like to add to the table.
421 You could add a table row with code similar to this:
423 function demo_identities_table(&$args)
425 return '<tr bgcolor="' . $args[0] . '"><td> </td><td>'
426 . 'YOUR CODE HERE' . '</td></tr>' . "\n";
429 options_identities_buttons
431 This hook allows you to add a button (or other HTML) to the row of
432 buttons under each identity. The arguments to this hook are:
434 [0] = is this an empty section (the one at the end of the list)?
435 [1] = what is the 'post' value? (ident # or empty string if default)
437 You need to return any HTML you would like to add here. You could add
438 a button with code similar to this:
440 function demo_identities_button(&$args)
442 return '<input type="submit" name="demo_button_' . $args[1]
443 . '" value="Press Me" />';
449 When a message has attachments, this hook is called with the MIME types. For
450 instance, a .zip file hook is "attachment application/x-zip". The hook should
451 probably show a link to do a specific action, such as "Verify" or "View" for a
452 .zip file. Thus, to register your plugin for .zip attachments, you'd do this
453 in setup.php (assuming your plugin is called "demo"):
455 $squirrelmail_plugin_hooks['attachment application/x-zip']['demo']
456 = 'demo_handle_zip_attachment';
458 This is a breakdown of the data passed in the array to the hook that is called:
460 [0] = Hook's name ('attachment text/plain')
461 [1] = Array of links of actions (see below) (alterable)
462 [2] = Used for returning to mail message (startMessage)
463 [3] = Used for finding message to display (id)
464 [4] = Mailbox name, urlencode()'d (urlMailbox)
465 [5] = Entity ID inside mail message (ent)
466 [6] = Default URL to go to when filename is clicked on (alterable)
467 [7] = Filename that is displayed for the attachment
468 [8] = Sent if message was found from a search (where)
469 [9] = Sent if message was found from a search (what)
471 To set up links for actions, you assign them like this:
473 $Args[1]['<plugin_name>']['href'] = 'URL to link to';
474 $Args[1]['<plugin_name>']['text'] = 'What to display';
476 It's also possible to specify a hook as "attachment type0/*",
477 for example "attachment text/*". This hook will be executed whenever there's
478 no more specific rule available for that type.
480 Putting all this together, the demo_handle_zip_attachment() function should
481 look like this (note the argument being passed):
483 function demo_handle_zip_attachment(&$Args)
485 include_once(SM_PATH . 'plugins/demo/functions.php');
486 demo_handle_zip_attachment_do($Args);
489 And the demo_handle_zip_attachment_do() function in the
490 plugins/demo/functions.php file would typically (but not necessarily)
491 display a custom link:
493 function demo_handle_zip_attachment_do(&$Args)
495 $Args[1]['demo']['href'] = SM_PATH . 'plugins/demo/zip_handler.php?'
496 . 'passed_id=' . $Args[3] . '&mailbox=' . $Args[4]
497 . '&passed_ent_id=' . $Args[5];
498 $Args[1]['demo']['text'] = 'show zip contents';
501 The file plugins/demo/zip_handler.php can now do whatever it needs with the
502 attachment (note that this will hand information about how to retrieve the
503 source message from the IMAP server as GET varibles).
508 Before you start adding user preferences to your plugin, please take a moment
509 to think about it: in some cases, more options may not be a good thing.
510 Having too many options can be confusing. Thinking from the user's
511 perspective, will the proposed options actually be used? Will users
512 understand what these options are for?
514 There are two ways to add options for your plugin. When you only have a few
515 options that don't merit an entirely new preferences page, you can incorporate
516 them into an existing section of SquirrelMail preferences (Personal
517 Information, Display Preferences, Message Highlighting, Folder Preferences or
518 Index Order). Or, if you have an extensive number of settings or for some
519 reason need a separate page for the user to interact with, you can create your
520 own preferences page.
523 Integrating Your Options Into Existing SquirrelMail Preferences Pages
524 ---------------------------------------------------------------------
526 There are two ways to accomplish the integration of your plugin's settings
527 into another preferences page. The first method is to add the HTML code
528 for your options directly to the preferences page of your choice. Although
529 currently very popular, this method will soon be deprecated, so avoid it
530 if you can. That said, here is how it works. :) Look for any of the hooks
531 named as "options_<pref page>_inside", where <pref page> is "display",
532 "personal", etc. For this example, we'll use "options_display_inside" and,
533 as above, "demo" as our plugin name:
535 1. In setup.php in the squirrelmail_plugin_init_demo() function:
537 $squirrelmail_plugin_hooks['options_display_inside']['demo']
538 = 'demo_show_options';
540 Note that there are also hooks such as "options_display_bottom",
541 however, they place your options at the bottom of the preferences
542 page, which is usually not desirable (mostly because they also
543 come AFTER the HTML FORM tag is already closed). It is possible
544 to use these hooks if you want to create your own FORM with custom
547 2. Assuming the function demo_show_options() calls another function
548 elsewhere called demo_show_options_do(), that function should have
549 output similar to this (note that you will be inserting code into
550 a table that is already defined with two columns, so please be sure
551 to keep this framework in your plugin):
553 ------cut here-------
562 ------cut here-------
564 Of course, you can place any text where OPTION_NAME is and any input
565 tags where OPTION_INPUT is.
567 3. You will want to use the "options_<pref page>_save" hook (in this case,
568 "options_display_save") to save the user's settings after they have
569 pressed the "Submit" button. Again, back in setup.php in the
570 squirrelmail_plugin_init_demo() function:
572 $squirrelmail_plugin_hooks['options_display_save']['demo']
573 = 'demo_save_options';
575 4. Assuming the function demo_save_options() calls another function
576 elsewhere called demo_save_options_do(), that function should put
577 the user's settings into permanent storage (see the preferences
578 section below for more information). This example assumes that
579 in the preferences page, the INPUT tag's NAME attribute was set
582 global $data_dir, $username;
583 sqgetGlobalVar('demo_option', $demo_option);
584 setPref($data_dir, $username, 'demo_option', $demo_option);
587 The second way to add options to one of the SquirrelMail preferences page is
588 to use one of the "optpage_loadhook_<pref page>" hooks. The sent_subfolders
589 plugin has an excellent example of this method. Briefly, this way of adding
590 options consists of adding some plugin-specific information to a predefined
591 data structure which SquirrelMail then uses to build the HTML input forms
592 for you. This is the preferred method of building options lists going forward.
594 1. We'll use the "optpage_loadhook_display" hook to add a new group of
595 options to the display preferences page. In setup.php in the
596 squirrelmail_plugin_init_demo() function:
598 $squirrelmail_plugin_hooks['optpage_loadhook_display']['demo']
601 2. Assuming the function demo_options() calls another function elsewhere
602 called demo_options_do(), that function needs to add a new key to two
603 arrays, $optpage_data['grps'] and $optpage_data['vals']. The value
604 associated with that key should simply be a section heading for your
605 plugin on the preferences page for the $optpage_data['grps'] array,
606 and yet another array with all of your plugin's options for the
607 $optpage_data['vals'] array. The options are built as arrays (yes,
608 that's four levels of nested arrays) that specify attributes that are
609 used by SquirrelMail to build your HTML input tags automatically.
610 This example includes just one input element, a SELECT (drop-down)
613 global $optpage_data;
614 $optpage_data['grps']['DEMO_PLUGIN'] = 'Demo Options';
615 $optionValues = array();
616 $optionValues[] = array(
617 'name' => 'plugin_demo_favorite_color',
618 'caption' => 'Please Choose Your Favorite Color',
619 'type' => SMOPT_TYPE_STRLIST,
620 'refresh' => SMOPT_REFRESH_ALL,
621 'posvals' => array(0 => 'red',
625 'save' => 'save_plugin_demo_favorite_color'
627 $optpage_data['vals']['DEMO_PLUGIN'] = $optionValues;
629 The array that you use to specify each plugin option has the following
632 name The name of this setting, which is used not only for
633 the INPUT tag name, but also for the name of this
634 setting in the user's preferences
635 caption The text that prefaces this setting on the preferences
637 trailing_text Text that follows a text input or select list input on
638 the preferences page (useful for indicating units,
639 meanings of special values, etc.)
640 type The type of INPUT element, which should be one of:
641 SMOPT_TYPE_STRING String/text input
642 SMOPT_TYPE_STRLIST Select list input
643 SMOPT_TYPE_TEXTAREA Text area input
644 SMOPT_TYPE_INTEGER Integer input
645 SMOPT_TYPE_FLOAT Floating point number input
646 SMOPT_TYPE_BOOLEAN Boolean (yes/no radio buttons)
648 SMOPT_TYPE_HIDDEN Hidden input (not actually
649 shown on preferences page)
650 SMOPT_TYPE_COMMENT Text is shown (specified by the
651 'comment' attribute), but no
653 SMOPT_TYPE_FLDRLIST Select list of IMAP folders
654 refresh Indicates if a link should be shown to refresh part or
655 all of the window (optional). Possible values are:
656 SMOPT_REFRESH_NONE No refresh link is shown
657 SMOPT_REFRESH_FOLDERLIST Link is shown to refresh
659 SMOPT_REFRESH_ALL Link is shown to refresh
661 initial_value The value that should initially be placed in this
663 posvals For select lists, this should be an associative array,
664 where each key is an actual input value and the
665 corresponding value is what is displayed to the user
666 for that list item in the drop-down list
667 value Specify the default/preselected value for this option
669 save You may indicate that special functionality needs to be
670 used instead of just saving this setting by giving the
671 name of a function to call when this value would
672 otherwise just be saved in the user's preferences
673 size Specifies the size of certain input items (typically
674 textual inputs). Possible values are:
681 comment For SMOPT_TYPE_COMMENT type options, this is the text
682 displayed to the user
683 script This is where you may add any additional javascript
684 or other code to the user input
685 post_script You may specify some script (usually Javascript) that
686 will be placed after (outside of) the INPUT tag.
688 Note that you do not have to create a whole new section on the options
689 page if you merely want to add a simple input item or two to an options
690 section that already exists. For example, the Display Options page has
693 0 - General Display Options
694 1 - Mailbox Display Options
695 2 - Message Display and Composition
697 To add our previous input drop-down to the Mailbox Display Options,
698 we would not have to create our own group; just add it to group
701 global $optpage_data;
702 $optpage_data['vals'][1][] = array(
703 'name' => 'plugin_demo_favorite_color',
704 'caption' => 'Please Choose Your Favorite Color',
705 'type' => SMOPT_TYPE_STRLIST,
706 'refresh' => SMOPT_REFRESH_ALL,
707 'posvals' => array(0 => 'red',
711 'save' => 'save_plugin_demo_favorite_color'
714 3. If you indicated a 'save' attribute for any of your options, you must
715 create that function (you'll only need to do this if you need to do
716 some special processing for one of your settings). The function gets
717 one parameter, which is an object with mostly the same attributes you
718 defined when you made the option above... the 'new_value' (and possibly
719 'value', which is the current value for this setting) is the most useful
720 attribute in this context:
722 function save_plugin_demo_favorite_color($option)
724 // if user chose orange, make note that they are really dumb
725 if ($option->new_value == 3)
727 // more code here as needed
730 // don't even save this setting if user chose green (old
731 // setting will remain)
732 if ($option->new_value == 2)
735 // for all other colors, save as normal
736 save_option($option);
740 Creating Your Own Preferences Page
741 ----------------------------------
743 It is also possible to create your own preferences page for a plugin. This
744 is particularly useful when your plugin has numerous options or needs to
745 offer special interaction with the user (for things such as changing password,
746 etc.). Here is an outline of how to do so (again, using the "demo" plugin
749 1. Add a new listing to the main Options page. Older versions of
750 SquirrelMail offered a hook called "options_link_and_description"
751 although its use is deprecated (and it is harder to use in that
752 it requires you to write your own HTML to add the option). Instead,
753 you should always use the "optpage_register_block" hook where you
754 create a simple array that lets SquirrelMail build the HTML
755 to add the plugin options entry automatically. In setup.php in the
756 squirrelmail_plugin_init_demo() function:
758 $squirrelmail_plugin_hooks['optpage_register_block']['demo']
759 = 'demo_options_block';
761 2. Assuming the function demo_options_block() calls another function
762 elsewhere called demo_options_block_do(), that function only needs
763 to create a simple array and add it to the $optpage_blocks array:
765 global $optpage_blocks;
766 $optpage_blocks[] = array(
767 'name' => 'Favorite Color Settings',
768 'url' => SM_PATH . 'plugins/demo/options.php',
769 'desc' => 'Change your favorite color & find new exciting colors',
773 The array should have four elements:
774 name The title of the plugin's options as it will be displayed on
776 url The URI that points to your plugin's custom preferences page
777 desc A description of what the preferences page offers the user,
778 displayed on the Options page below the title
779 js Indicates if this option page requires the client browser
780 to be Javascript-capable. Should be TRUE or FALSE.
782 3. There are two different ways to create the actual preferences page
783 itself. One is to simply write all of your own HTML and other
784 interactive functionality, while the other is to define some data
785 structures that allow SquirrelMail to build your user inputs and save
786 your data automatically.
788 Building your own page is wide open, and for ideas, you should look at
789 any of the plugins that currently have their own preferences pages. If
790 you do this, make sure to read step number 4 below for information on
791 saving settings. In order to maintain security, consistant look and
792 feel, internationalization support and overall integrity, there are just
793 a few things you should always do in this case: define the SM_PATH
794 constant, include the file include/validate.php (see the section about
795 including other files above) and make a call to place the standard page
796 heading at the top of your preferences page. The top of your PHP file
797 might look something like this:
799 define('SM_PATH', '../../');
800 include_once(SM_PATH . 'include/validate.php');
802 displayPageHeader($color, 'None');
804 From here you are on your own, although you are encouraged to do things
805 such as use the $color array to keep your HTML correctly themed, etc.
807 If you want SquirrelMail to build your preferences page for you,
808 creating input forms and automatically saving users' settings, then
809 you should change the 'url' attribute in the options block you created
810 in step number 2 above to read as follows:
812 'url' => SM_PATH . 'src/options.php?optpage=plugin_demo',
814 Now, you will need to use the "optpage_set_loadinfo" hook to tell
815 SquirrelMail about your new preferences page. In setup.php in the
816 squirrelmail_plugin_init_demo() function:
818 $squirrelmail_plugin_hooks['optpage_set_loadinfo']['demo']
819 = 'demo_optpage_loadinfo';
821 Assuming the function demo_optpage_loadinfo() calls another function
822 elsewhere called demo_optpage_loadinfo_do(), that function needs to
823 define values for four variables (make sure you test to see that it
824 is your plugin that is being called by checking the GET variable you
825 added to the url just above):
827 global $optpage, $optpage_name, $optpage_file,
828 $optpage_loader, $optpage_loadhook;
829 if ($optpage == 'plugin_demo')
831 $optpage_name = "Favorite Color Preferences";
832 $optpage_file = SM_PATH . 'plugins/demo/options.php';
833 $optpage_loader = 'load_optpage_data_demo';
834 $optpage_loadhook = 'optpage_loadhook_demo';
837 Now you are ready to build all of your options. In the file you
838 indicated for the variable $optpage_file above, you'll need to create
839 a function named the same as the value you used for $optpage_loader
840 above. In this example, the file plugins/demo/options.php should
841 have at least this function in it:
843 function load_optpage_data_demo()
845 $optpage_data = array();
846 $optpage_data['grps']['DEMO_PLUGIN'] = 'Demo Options';
847 $optionValues = array();
848 $optionValues[] = array(
849 'name' => 'plugin_demo_favorite_color',
850 'caption' => 'Please Choose Your Favorite Color',
851 'type' => SMOPT_TYPE_STRLIST,
852 'refresh' => SMOPT_REFRESH_ALL,
853 'posvals' => array(0 => 'red',
857 'save' => 'save_plugin_demo_favorite_color'
859 $optpage_data['vals']['DEMO_PLUGIN'] = $optionValues;
860 return $optpage_data;
863 For a detailed description of how you build these options, please read
864 step number 2 for the second method of adding options to an existing
865 preferences page above. Notice that the only difference here is in the
866 very first and last lines of this function where you are actually
867 creating and returning the options array instead of just adding onto it.
869 That's all there is to it - SquirrelMail will create a preferences page
870 titled as you indicated for $optpage_name above, and other plugins
871 can even add extra options to this new preferences page. To do so,
872 they should use the hook name you specified for $optpage_loadhook above
873 and use the second method for adding option settings to existing
874 preferences pages described above.
876 4. Saving your options settings: if you used the second method in step
877 number 3 above, your settings will be saved automatically (or you can
878 define special functions to save special settings such as the
879 save_plugin_demo_favorite_color() function in the example described
880 above) and there is probably no need to follow this step. If you
881 created your own preferences page from scratch, you'll need to follow
882 this step. First, you need to register your plugin against the
883 "options_save" hook. In setup.php in the squirrelmail_plugin_init_demo()
886 $squirrelmail_plugin_hooks['options_save']['demo']
887 = 'demo_save_options';
889 Assuming the function demo_save_options() calls another function
890 elsewhere called demo_save_options_do(), that function needs to grab
891 all of your POST and/or GET settings values and save them in the user's
892 preferences (for more about preferences, see that section below). Since
893 this is a generic hook called for all custom preferences pages, you
894 should always set "optpage" as a POST or GET variable with a string that
895 uniquely identifies your plugin:
897 <input type="hidden" name="optpage" value="plugin_demo" />
899 Now in your demo_save_options_do() function, do something like this:
901 global $username, $data_dir, $optpage, $favorite_color;
902 if ($optpage == 'plugin_demo')
904 sqgetGlobalVar('favorite_color', $favorite_color, SQ_FORM);
905 setPref($data_dir, $username, 'favorite_color', $favorite_color);
908 Note that $favorite_color may not need to be globalized, although
909 experience has shown that some versions of PHP don't behave as expected
910 unless you do so. Even when you use SquirrelMail's built-in preferences
911 page generation functionality, you may still use this hook, although
912 there should be no need to do so. If you need to do some complex
913 validation routines, note that it might be better to do so in the file
914 you specified as the "$optpage_file" (in our example, that was the
915 plugins/demo/options.php file), since at this point, you can still
916 redisplay your preferences page. You could put code similar to this
917 in the plugins/demp/options.php file (note that there is no function;
918 this code needs to be executed at include time):
921 if ($optmode == 'submit')
923 // do something here such as validation, etc
924 if (you want to redisplay your preferences page)
932 Saving and retrieving user preferences is very easy in SquirrelMail.
933 SquirrelMail supports preference storage in files or in a database
934 backend, however, the code you need to write to manipulate preferences
935 is the same in both cases.
939 Setting preferences is done for you if you use the built-in facilities
940 for automatic options construction and presentation (see above). If
941 you need to manually set preferences, however, all you need to do is:
943 global $data_dir, $username;
944 setPref($data_dir, $username, 'pref_name', $pref_value);
946 Where "pref_name" is the key under which the value will be stored
947 and "pref_value" is a variable that should contain the actual
948 preference value to be stored.
952 There are two approaches to retrieving plugin (or any other) preferences.
953 You can grab individual preferences one at a time or you can add your
954 plugin's preferences to the routine that loads up user preferences at
955 the beginning of each page request. If you do the latter, making sure
956 to place your preference variables into the global scope, they will be
957 immediately available in all other plugin code. To retrieve a single
958 preference value at any time, do this:
960 global $data_dir, $username;
961 $pref_value = getPref($data_dir, $username, 'pref_name', 'default value');
963 Where "pref_name" is the preference you are retrieving, "default_value"
964 is what will be returned if the preference is not found for this user,
965 and, of course, "pref_value" is the variable that will get the actual
968 To have all your preferences loaded at once when each page request is
969 made, you'll need to register a function against the "loading_prefs" hook.
970 For our "demo" plugin, in setup.php in the squirrelmail_plugin_init_demo()
973 $squirrelmail_plugin_hooks['loading_prefs']['demo']
976 Assuming the function demo_load_prefs() calls another function
977 elsewhere called demo_load_prefs_do(), that function just needs to
978 pull out any all all preferences you'll be needing elsewhere:
980 global $data_dir, $username, $pref_value;
981 $pref_value = getPref($data_dir, $username, 'pref_name', 'default value');
983 Remember to globalize each preference, or this code is useless.
989 Although this document may only be available in English, we sure hope that you
990 are thinking about making your plugin useful to the thousands of non-English
991 speaking SquirrelMail users out there! It is almost rude not to do so, and
992 it isn't much trouble, either. This document will only describe how you can
993 accomplish the internationalization of a plugin. For more general information
994 about PHP and SquirrelMail translation facilities, see:
996 http://www.squirrelmail.org/wiki/wiki.php?LanguageTranslation
998 The unofficial way to internationalize a plugin is to put all plugin output
999 into the proper format but to rely on the SquirrelMail translation facilities
1000 for all the rest. If the plugin were really to get translated, you'd need
1001 to make sure that all output strings for your plugin are either added to or
1002 already exist in the main SquirrelMail locale files.
1004 The better way to make sure your plugin is translated is to create your own
1005 locale files and what is called a "gettext domain" (see the link above for
1008 There are three basic steps to getting your plugins internationalized: put
1009 all output into the proper format, switch gettext domains and create locale
1012 1. Putting plugin output into the correct format is quite easy. The hard
1013 part is making sure you catch every last echo statement. You need to
1014 echo text like this:
1018 So, even in the HTML segments of your plugin files, you need to do this:
1020 <input type="submit" value="<?php echo _("Submit"); ?>" />
1022 You can put any text you want inside of the quotes (you MUST use double
1023 quotes!), including HTML tags, etc. What you should think carefully
1024 about is that some languages may use different word ordering, so this
1025 might be problematic:
1027 echo _("I want to eat a ") . $fruitName . _(" before noon");
1029 Because some languages (Japanese, for instance) would need to translate
1030 such a sentence to "Before noon " . $fruitName . " I want to eat", but
1031 with the format above, they are stuck having to translate each piece
1032 separately. You might want to reword your original sentence:
1034 echo _("This is what I want to eat before noon: ") . $fruitName;
1036 2. By default, the SquirrelMail gettext domain is always in use. That
1037 means that any text in the format described above will be translated
1038 using the locale files found in the main SquirrelMail locale directory.
1039 Unless your plugin produces no output or only output that is in fact
1040 translated under the default SquirrelMail domain, you need to create
1041 your own gettext domain. The PHP for doing so is very simple. At
1042 the top of any file that produces any output, place the following code
1043 (again, using "demo" as the plugin name):
1045 bindtextdomain('demo', SM_PATH . 'plugins/demo/locale');
1048 Now all output will be translated using your own custom locale files.
1049 Please be sure to switch back to the SquirrelMail domain at the end
1050 of the file, or many of the other SquirrelMail files may misbehave:
1052 bindtextdomain('squirrelmail', SM_PATH . 'locale');
1053 textdomain('squirrelmail');
1055 Note that if, in the middle of your plugin file, you use any
1056 SquirrelMail functions that send output to the browser, you'll need
1057 to temporarily switch back to the SquirrelMail domain:
1059 bindtextdomain('squirrelmail', SM_PATH . 'locale');
1060 textdomain('squirrelmail');
1061 displayPageHeader($color, 'None');
1062 bindtextdomain('demo', SM_PATH . 'plugins/demo/locale');
1065 Note that technically speaking, you only need to have one bindtextdomain
1066 call per file, you should always use it before every textdomain call,
1067 since PHP installations without gettext compiled into them will not
1068 function properly if you do not.
1070 3. Finally, you just need to create your own locale. You should create
1071 a directory structure like this in the plugin directory:
1085 Create a directories such as de_DE for each language (de_DE is German,
1086 ja_JP is Japanese, etc. - check the SquirrelMail locale directory for
1087 a fairly comprehensive listing). Inside of each LC_MESSAGES directory
1088 you should place two files, one with your translations in it, called
1089 <plugin name>.po (in this case, "demo.po"), and one that is a compiled
1090 version of the ".po" file, called <plugin name>.mo (in this case,
1091 "demo.mo"). On most linux systems, there is a tool you can use to pull
1092 out most of the strings that you need to have translated from your PHP
1093 files into a sample .po file:
1095 xgettext --keyword=_ -d <plugin name> -s -C *.php
1097 --keyword option tells xgettext what your strings are enclosed in
1098 -d is the domain of your plugin which should be the plugin's name
1099 -s tells xgettext to sort the results and remove duplicate strings
1100 -C means you are translating a file with C/C++ type syntax (ie. PHP)
1101 *.php is all the files you want translations for
1103 Note, however, that this will not always pick up all strings, so you
1104 should double-check manually. Of course, it's easiest if you just keep
1105 track of all your strings as you are coding your plugin. Your .po file
1106 will now look something like:
1108 # SOME DESCRIPTIVE TITLE.
1109 # Copyright (C) YEAR Free Software Foundation, Inc.
1110 # FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
1115 "Project-Id-Version: PACKAGE VERSION\n"
1116 "POT-Creation-Date: 2003-06-18 11:22-0600\n"
1117 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
1118 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
1119 "Language-Team: LANGUAGE <LL@li.org>\n"
1120 "MIME-Version: 1.0\n"
1121 "Content-Type: text/plain; charset=CHARSET\n"
1122 "Content-Transfer-Encoding: ENCODING\n"
1129 msgid "Favorite Color"
1132 You should change the header to look something more like:
1134 # Copyright (c) 1999-2003 The Squirrelmail Development Team
1135 # Roland Bauerschmidt <rb@debian.org>, 1999.
1139 "Project-Id-Version: plugin-name version\n"
1140 "POT-Creation-Date: 2003-01-21 19:21+0100\n"
1141 "PO-Revision-Date: 2003-01-21 21:01+0100\n"
1142 "Last-Translator: Juergen Edner <juergen.edner@epost.de>\n"
1143 "Language-Team: German <squirrelmail-i18n@lists.squirrelmail.net>\n"
1144 "MIME-Version: 1.0\n"
1145 "Content-Type: text/plain; charset=ISO-8859-1\n"
1146 "Content-Transfer-Encoding: 8bit\n"
1148 The most important thing to change here is the charset on the next to
1149 last line. You'll want to keep a master copy of the .po file and make
1150 a copy for each language you have a translation for. You'll need to
1151 translate each string in the .po file:
1156 After you're done translating, you can create the .mo file very simply
1157 by running the following command (available on most linux systems):
1159 msgfmt -o <plugin name>.mo <plugin name>.po
1161 In the case of the "demo" plugin:
1163 msgfmt -o demo.mo demo.po
1165 Please be sure that the .po and .mo files both are named exactly the
1166 same as the domain you bound in step 2 above and everything else works
1167 automatically. In SquirrelMail, go to Options -> Display Preferences
1168 and change your Language setting to see the translations in action!
1172 Documenting the Code (Optional)
1173 -------------------------------
1175 If you wish, you can use phpdoc (Javadoc-style) comments, when documenting your
1178 If you follow the standards that are followed between Squirrelmail core &
1179 plugin developers, the resulted documentation can be included with the rest of
1180 the Squirrelmail code & API documentation. Specifically, in the page-level
1181 docblock, declare the package to be 'plugins', and the subpackage to be the
1182 name of your plugin. For instance:
1187 * Copyright (c) 2003 My Name <my-email-address>
1188 * Licensed under the GNU GPL. For full terms see the file COPYING.
1194 The rest is up to you. Try to follow some common sense and document what is
1195 really needed. Documenting the code properly can be a big help not only to
1196 yourself, but to those who will take a look at your code, fix the bugs and even
1197 improve it, in the true open-source spirit that Squirrelmail was built upon.
1199 For more information about phpdocumentor and how to write proper-tagged
1200 comments, you are directed at:
1202 http://phpdocu.sourceforge.net/
1206 PLUGIN STANDARDS AND REQUIREMENTS
1207 =================================
1209 The SquirrelMail project has some important goals, such as avoiding the
1210 use of JavaScript, avoiding non-standard HTML tags, keeping file sizes
1211 small and providing the fastest webmail client on the Internet. As such,
1212 we'd like it if plugin authors coded with the same goals in mind that the
1213 core developers do. Common sense is always a good tool to have in your
1214 programming repertoire, but below is an outline of some standards that we
1215 ask you as a plugin developer to meet. Depending upon how far you bend
1216 these rules, we may not want to post your plugin on the SquirrelMail
1217 website... and of course, no one really wants your efforts to go to waste
1218 and for the SquirrelMail community to miss out on a potentially useful
1219 plugin, so please try to follow these guidelines as closely as possible.
1225 In order for SquirrelMail to remain fast and lean, we are now asking
1226 that all plugin authors remove all unnecessary functionality from setup.php
1227 and refactor it into another file. There are a few ways to accomplish
1228 this, none of which are difficult. At a minimum, you'll want to have the
1229 squirrelmail_plugin_init_<plugin name>() function in setup.php, and naturally,
1230 you'll need functions that are merely stubs for each hook that you are using.
1231 One (but not the only) way to do it is:
1233 function squirrelmail_plugin_init_demo()
1235 global $squirrelmail_plugin_hooks;
1236 $squirrelmail_plugin_hooks['generic_header']['demo'] = 'plugin_demo_header';
1238 function plugin_demo_header()
1240 include_once(SM_PATH . 'plugins/demo/functions.php');
1241 plugin_demo_header_do();
1245 Internationalization
1246 --------------------
1248 Q: What is more disappointing to users in France who would make good
1249 use of your plugin than learning that it is written entirely in English?
1250 A: Learning that they cannot send you a French translation file for your
1253 There are thousands of users out there whose native tongue is not English,
1254 and when you develop your plugin without going through the three simple steps
1255 needed to internationalize it, you are effectively writing them all off.
1256 PLEASE consider internationalizing your plugin!
1259 Developing with E_ALL
1260 ---------------------
1262 When you are developing your plugin, you should always have error reporting
1263 turned all the way up. You can do this by changing two settings in your
1264 php.ini and restarting your web server:
1267 error_reporting = E_ALL
1269 This way, you'll be sure to see all Notices, Warnings and Errors that your
1270 code generates (it's OK, really, it happens to the best of us... except me!).
1271 Please make sure to fix them all before you release the plugin.
1274 Compatibility with register_globals=Off
1275 ---------------------------------------
1277 Most sensible systems administrators now run their PHP systems with the
1278 setting "register_globals" as OFF. This is a prudent security setting,
1279 and as the SquirrelMail core code has long since been upgraded to work
1280 in such an environment, we are now requiring that all plugins do the same.
1281 Compatibility with this setting amounts to little more than explicitly
1282 gathering any and all variables you sent from a <form> tag as GET or POST
1283 values instead of just assuming that they will be placed in the global
1284 scope automatically. There is nothing more to do than this:
1286 global $favorite_color;
1287 sqgetGlobalVar('favorite_color', $favorite_color, SQ_FORM);
1293 It may seem innocuous, but if you have any blank lines either before the
1294 first <?php tag or after the last ?> tag in any of your plugin files, you
1295 you will break SquirrelMail in ways that may seem entirely unrelated. For
1296 instance, this will often cause a line feed character to be included with
1297 email attachments when they are viewed or downloaded, rendering them useless!
1303 When including files, please make sure to use the include_once() function
1304 and NOT include(), require(), or require_once(), since these all are much
1305 less efficient than include_once() and can have a cumulative effect on
1306 SquirrelMail performance.
1312 In order for systems administrators to keep better track of your plugin and
1313 get upgrades more efficiently, you are requested to make version information
1314 available to SquirrelMail in a format that it understands. There are two
1315 ways to do this. Presently, we are asking that you do both, since we are
1316 still in a transition period between the two. This is painless, so please
1317 be sure to include it:
1319 1. Create a file called "version" in the plugin directory. That file
1320 should have only two lines: the first line should have the name of
1321 the plugin as named on the SquirrelMail web site (this is often a
1322 prettified version of the plugin directory name), the second line
1323 must have the version and nothing more. So for our "demo" plugin,
1324 whose name on the web site might be something like "Demo Favorite
1325 Colors", the file plugins/demo/version should have these two lines:
1327 Demo Favorite Colors
1330 2. In setup.php, you should have a function called <plugin name>_version().
1331 That function should return the version of your plugin. For the "demo"
1332 plugin, that should look like this:
1334 function demo_version()
1343 It is common to need a configuration file that holds some variables that
1344 are set up at install time. For ease of installation and maintenance, you
1345 should place all behavioral settings in a config file, isolated from the
1346 rest of your plugin code. A typical file name to use is "config.php". If
1347 you are using such a file, you should NOT include a file called "config.php"
1348 in your plugin distribution, but instead a copy of that file called
1349 "config.php.sample". This helps systems administrators avoid overwriting
1350 the "config.php" files and losing all of their setup information when they
1351 upgrade your plugin.
1357 In the past, there have been some rather serious issues with PHP sessions
1358 and SquirrelMail, and certain people have worked long and hard to ensure
1359 that these problems no longer occur in an extremely wide variety of OS/PHP/
1360 web server environments. Thus, if you need to place any values into the
1361 user's session, there are some built-in SquirrelMail functions that you are
1362 strongly encouraged to make use of. Using them also makes your job easier.
1364 1. To place a variable into the session:
1366 global $favorite_color;
1367 $favoriteColor = 'green';
1368 sqsession_register($favorite_color, 'favorite_color');
1370 Strictly speaking, globalizing the variable shouldn't be necessary,
1371 but certain versions of PHP seem to behave more predictably if you do.
1373 2. To retrieve a variable from the session:
1375 global $favorite_color;
1376 sqgetGlobalVar('favorite_color', $favorite_color, SQ_SESSION);
1378 3. You can also check for the presence of a variable in the session:
1380 if (sqsession_is_registered('favorite_color'))
1381 // do something important
1383 4. To remove a variable from the session:
1385 global $favorite_color;
1386 sqsession_unregister('favorite_color');
1388 Strictly speaking, globalizing the variable shouldn't be necessary,
1389 but certain versions of PHP seem to behave more predictably if you do.
1395 You are also encouraged to use SquirrelMail's built-in facilities to
1396 retrieve variables from POST and GET submissions. This is also much
1397 easier on you and makes sure that all PHP installations are accounted
1398 for (such as those that don't make the $_POST array automatically
1401 global $favorite_color;
1402 sqgetGlobalVar('favorite_color', $favorite_color, SQ_FORM);
1405 Files In Plugin Directory
1406 -------------------------
1408 There are a few files that you should make sure to include when you build
1409 your final plugin distribution:
1411 1. A copy of the file index.php from the main plugins directory. When
1412 working in your plugin directory, just copy it in like this:
1416 This will redirect anyone who tries to browse to your plugin directory
1417 to somewhere more appropriate. If you create other directories under
1418 your plugin directory, you may copy the file there as well to be extra
1419 safe. If you are storing sensitive configuration files or other data
1420 in such a directory, you could even include a .htaccess file with the
1421 contents "Deny From All" that will disallow access to that directory
1422 entirely (when the target system is running the Apache web server).
1423 Keep in mind that not all web servers will honor an .htaccess file, so
1424 don't depend on it for security. Make sure not to put such a file in
1425 your main plugin directory!
1427 2. A file that describes your plugin and offers detailed instructions for
1428 configuration or help with troubleshooting, etc. This file is usually
1429 entitled "README". Some useful sections to include might be:
1431 Plugin Name and Author
1434 Detailed Plugin Description
1435 How-to for Plugin Configuration
1437 Future Ideas/Enhancements/To Do List
1439 3. A file that explains how to install your plugin. This file is typically
1440 called "INSTALL". If you do not require any special installation
1441 actions, you can probably copy one from another plugin or use this as
1444 Installing the Demo Plugin
1445 ==========================
1447 1) Start with untaring the file into the plugins directory.
1448 Here is a example for the 1.0 version of the Demo plugin.
1451 $ tar -zxvf demo-1.0-1.4.0.tar.gz
1453 2) Change into the demo directory, copy config.php.sample
1454 to config.php and edit config.php, making adjustments as
1455 you deem necessary. For more detailed explanations about
1456 each of these parameters, consult the README file.
1459 $ cp config.php.sample config.php
1463 3) Then go to your config directory and run conf.pl. Choose
1464 option 8 and move the plugin from the "Available Plugins"
1465 category to the "Installed Plugins" category. Save and exit.
1471 Upgrading the Demo Plugin
1472 =========================
1474 1) Start with untaring the file into the plugins directory.
1475 Here is a example for the 3.1 version of the demo plugin.
1478 $ tar -zxvf demo-3.1-1.4.0.tar.gz
1481 2) Change into the demo directory, check your config.php
1482 file against the new version, to see if there are any new
1483 settings that you must add to your config.php file.
1485 $ diff -Nau config.php config.php.sample
1487 Or simply replace your config.php file with the provided sample
1488 and reconfigure the plugin from scratch (see step 2 under the
1489 installation procedure above).
1492 COMPATIBILITY WITH OLDER VERSIONS OF SQUIRRELMAIL
1493 =================================================
1495 Whenever new versions of SquirrelMail are released, there is always a
1496 considerable lag time before it is widely adopted. During that transitional
1497 time, especially when the new SquirrelMail version contains any architectural
1498 and/or functional changes, plugin developers are put in a unique and very
1499 difficult position. That is, there will be people running both the old and
1500 new versions of SquirrelMail who want to use your plugin, and you will
1501 probably want to accomodate them both.
1503 The easiest way to keep both sides happy is to keep two different versions
1504 of your pluign up to date, one that runs under the older SquirrelMail, and
1505 one that requires the newest SquirrelMail. This is inconvenient, however,
1506 especially if you are continuing to develop the plugin. Depending on the
1507 changes the SquirrelMail has implemented in the new version, you may be able
1508 to include code that can auto-sense SquirrelMail version and make adjustments
1509 on the fly. There is a function available to you for determining the
1510 SquirrelMail version called check_sm_version() and it can be used as such:
1512 check_sm_version(1, 4, 0)
1514 This will return TRUE if the SquirrelMail being used is at least 1.4.0, and
1517 As this document is written, we are in a transition period between versions
1518 1.2.11 and 1.4.0. There is a plugin called "Compatibilty" that is intended
1519 for use by plugin authors so they can develop one version of their plugin
1520 and seamlessly support both 1.2.x and 1.4.x SquirrelMail installations. For
1521 more information about how to use the "Compatibility" plugin, download it and
1522 read its README file or see:
1524 http://www.squirrelmail.org/wiki/wiki.php?PluginUpgrading
1527 REQUESTING NEW HOOKS
1528 ====================
1530 It's impossible to foresee all of the places where hooks might be useful
1531 (it's also impossible to put in hooks everywhere!), so you might need to
1532 negotiate the insertion of a new hook to make your plugin work. In order
1533 to do so, you should post such a request to the squirrelmail-devel mailing
1537 HOW TO RELEASE YOUR PLUGIN
1538 ==========================
1540 As long as you've consulted the list of plugin standards and done your
1541 best to follow them, there's little standing in the way of great fame as an
1542 official SquirrelMail plugin developer.
1544 1. Make a distribution file. There is a convenient Perl script in
1545 the plugins directory that will help you do this:
1547 make_archive.pl -v demo 1.0 1.4.0
1549 -v is optional and indicates that the script should run in verbose mode
1550 demo is the name of your plugin
1551 1.0 is the version of your plugin
1552 1.4.0 is the version of SquirrelMail that is required to run your plugin
1554 You can also create the distribution file manually in most *nix
1555 environments by running this command from the plugins directory (NOT
1556 your plugin directory):
1558 $ tar czvf demo-1.0-1.4.0.tar.gz demo
1560 Where "demo" is the name of your plugin, "1.0" is the version of
1561 your plugin, and "1.4.0" is the version of SquirrelMail required
1564 2. Consult the SquirrelMail web site for contact information for the
1565 Plugins Team Leaders, to whom you should make your request. If they
1566 do not respond, you should feel free to ask for help contacting them
1567 on the squirrelmail-plugins mailing list.
1569 http://www.squirrelmail.org/wiki/wiki.php?SquirrelMailLeadership