54f1550ded294027135d9179a805bad9384de1d7
[squirrelmail.git] / doc / plugin.txt
1 $Id$
2
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)
7
8 FAQ -> http://www.squirrelmail.org/wiki/wiki.php?DeveloperFAQ
9 Plugin Development ->
10 http://www.squirrelmail.org/wiki/wiki.php?DevelopingPlugins
11
12
13 A FEW NOTES ON THE PLUGIN ARCHITECTURE
14 ======================================
15
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.
20
21
22 The Idea
23 --------
24
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".
29
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.
33
34 Some way for the plugins to interact with the help subsystem and
35 translations will be provided.
36
37
38 The Implementation
39 ------------------
40
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.
50
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.)
54
55 To start using a plugin, its name must be added to the $plugins array
56 in config.php like this:
57
58 $plugins[0] = 'plugin_name';
59
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.
64
65
66 WRITING PLUGINS
67 ===============
68
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.
75
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.
79
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/):
83
84 function squirrelmail_plugin_init_demo ()
85 {
86 global $squirrelmail_plugin_hooks;
87
88 $squirrelmail_plugin_hooks['generic_header']['demo'] = 'plugin_demo_header';
89 $squirrelmail_plugin_hooks['menuline']['demo'] = 'plugin_demo_menuline';
90 }
91
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.
96
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:
100
101 function plugin_demo_header()
102 {
103 include_once(SM_PATH . 'plugins/demo/functions.php');
104 plugin_demo_header_do();
105 }
106
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.
110
111
112 Including Other Files
113 ---------------------
114
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).
121
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:
129
130 define('SM_PATH', '../../');
131
132 Files are included like this:
133
134 include_once(SM_PATH . 'include/validate.php');
135
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.
140
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
152 versions.
153
154
155 Hook Types: Parameters and Return Values
156 -----------------------------------------
157
158 Hooks, when executed, are called with one parameter, an array of data
159 that is passed to the hook. The first element in the array is the name
160 of the hook that is being called. Any other elements in the array are
161 dependant on the type of hook that is being called. Most hooks do not
162 pass any other data, but be sure to check the hook you are using for
163 any useful information it may provide. Generally speaking, in the case
164 that any extra data is available here, your plugin should NOT change
165 it unless you know what you are doing or it is documented otherwise.
166 See below for further discussion of special hook types and the values
167
168 Most hooks, when executed, are called using the do_hook() function,
169 where no return value is used. There are a limited number of hooks,
170 however, that are called using the do_hook_function() and
171 concat_hook_function() function calls. Both of these hook types may
172 use the value returned by your plugin for its own purposes or to
173 display in the resultant HTML output (you need to research the specific
174 hook to determine its use). The do_hook_function() type hook will
175 only use the return value it retrieves from the LAST plugin in the
176 list of plugins registered against such a hook, whereas the
177 concat_hook_function() type hook will concatenate the return values
178 from all plugins that are registered against the hook and use that
179 value (usually as a string of HTML code to output to the client).
180
181
182 List of Hooks
183 -------------
184
185 This is a list of all hooks currently available in SquirrelMail, ordered
186 by file. Note that this list is accurate as of June 17, 2003 (should be
187 close to what is contained in release 1.4.1, plus or minus a hook or two),
188 but may be out of date soon thereafter. You never know. ;-)
189
190 Hook Name Found In Called With(#)
191 --------- -------- --------------
192 loading_constants functions/constants.php do_hook
193 get_pref_override functions/file_prefs.php hook_func
194 get_pref functions/file_prefs.php hook_func
195 special_mailbox functions/imap_mailbox.php hook_func
196 % rename_or_delete_folder functions/imap_mailbox.php hook_func
197 msg_envelope functions/mailbox_display.php do_hook
198 mailbox_index_before functions/mailbox_display.php do_hook
199 mailbox_form_before functions/mailbox_display.php do_hook
200 mailbox_index_after functions/mailbox_display.php do_hook
201 check_handleAsSent_result functions/mailbox_display.php do_hook
202 subject_link functions/mailbox_display.php concat_hook
203 message_body functions/mime.php do_hook
204 ^ attachment $type0/$type1 functions/mime.php do_hook
205 generic_header functions/page_header.php do_hook
206 menuline functions/page_header.php do_hook
207 loading_prefs include/load_prefs.php do_hook
208 addrbook_html_search_below src/addrbook_search_html.php do_hook
209 addressbook_bottom src/addressbook.php do_hook
210 compose_form src/compose.php do_hook
211 compose_bottom src/compose.php do_hook
212 compose_button_row src/compose.php do_hook
213 compose_send src/compose.php do_hook
214 folders_bottom src/folders.php do_hook
215 help_top src/help.php do_hook
216 help_chapter src/help.php do_hook
217 help_bottom src/help.php do_hook
218 left_main_after_each_folder src/left_main.php concat_hook
219 left_main_before src/left_main.php do_hook
220 left_main_after src/left_main.php do_hook
221 login_cookie src/login.php do_hook
222 login_top src/login.php do_hook
223 login_form src/login.php do_hook
224 login_bottom src/login.php do_hook
225 move_before_move src/move_messages.php do_hook
226 * optpage_set_loadinfo src/options.php do_hook
227 * optpage_loadhook_personal src/options.php do_hook
228 * optpage_loadhook_display src/options.php do_hook
229 * optpage_loadhook_highlight src/options.php do_hook
230 * optpage_loadhook_folder src/options.php do_hook
231 * optpage_loadhook_order src/options.php do_hook
232 * options_personal_save src/options.php do_hook
233 * options_display_save src/options.php do_hook
234 * options_folder_save src/options.php do_hook
235 * options_save src/options.php do_hook
236 * optpage_register_block src/options.php do_hook
237 * options_link_and_description src/options.php do_hook
238 * options_personal_inside src/options.php do_hook
239 * options_display_inside src/options.php do_hook
240 * options_highlight_inside src/options.php do_hook
241 * options_folder_inside src/options.php do_hook
242 * options_order_inside src/options.php do_hook
243 * options_personal_bottom src/options.php do_hook
244 * options_display_bottom src/options.php do_hook
245 * options_highlight_bottom src/options.php do_hook
246 * options_folder_bottom src/options.php do_hook
247 * options_order_bottom src/options.php do_hook
248 * options_highlight_bottom src/options_highlight.php do_hook
249 & options_identities_process src/options_identities.php do_hook
250 & options_identities_top src/options_identities.php do_hook
251 &% options_identities_renumber src/options_identities.php do_hook
252 & options_identities_table src/options_identities.php concat_hook
253 & options_identities_buttons src/options_identities.php concat_hook
254 message_body src/printer_friendly_bottom.php do_hook
255 read_body_header src/read_body.php do_hook
256 read_body_menu_top src/read_body.php do_hook
257 read_body_menu_bottom src/read_body.php do_hook
258 read_body_header_right src/read_body.php do_hook
259 html_top src/read_body.php do_hook
260 read_body_top src/read_body.php do_hook
261 read_body_bottom src/read_body.php do_hook
262 html_bottom src/read_body.php do_hook
263 login_before src/redirect.php do_hook
264 login_verified src/redirect.php do_hook
265 generic_header src/right_main.php do_hook
266 right_main_after_header src/right_main.php do_hook
267 right_main_bottom src/right_main.php do_hook
268 search_before_form src/search.php do_hook
269 search_after_form src/search.php do_hook
270 search_bottom src/search.php do_hook
271 logout src/signout.php do_hook
272 webmail_top src/webmail.php do_hook
273 webmail_bottom src/webmail.php do_hook
274 logout_above_text src/signout.php concat_hook
275
276 % = This hook is used in multiple places in the given file
277 # = Called with hook type (see below)
278 & = Special identity hooks (see below)
279 ^ = Special attachments hook (see below)
280 * = Special options hooks (see below)
281
282
283 (#) Called With
284 ---------------
285 Each hook is called using the hook type specified in the list above:
286 do_hook do_hook()
287 hook_func do_hook_function()
288 concat_hook concat_hook_function()
289
290
291 (&) Identity Hooks
292 ------------------
293 This set of hooks is passed special information in the array of arguments:
294
295 options_identities_process
296
297 This hook is called at the top of the Identities page, which is
298 most useful when the user has changed any identity settings - this
299 is where you'll want to save any custom information you are keeping
300 for each identity or catch any custom submit buttons that you may
301 have added to the identities page. The arguments to this hook are:
302
303 [0] = hook name (always "options_identities_process")
304 [1] = should I run the SaveUpdateFunction() (alterable)
305
306 Obviously, set the second array element to 1/true if you want to
307 trigger SaveUpdateFunction() after the hook is finished - by default,
308 it will not be called.
309
310 options_identities_renumber
311
312 This hook is called when one of the identities is being renumbered,
313 such as if the user had three identities and deletes the second -
314 this hook would be called with an array that looks like this:
315 ('options_identities_renumber', 2, 1). The arguments to this hook
316 are:
317
318 [0] = hook name (always "options_identities_renumber")
319 [1] = being renumbered from ('default' or 1 through (# idents) - 1)
320 [2] = being renumbered to ('default' or 1 through (# idents) - 1)
321
322 options_identities_table
323
324 This hook allows you to insert additional rows into the table that
325 holds each identity. The arguments to this hook are:
326
327 [0] = color of table (use it like this in your plugin:
328 <tr bgcolor="<?PHP echo $info[1]?>">
329 [1] = is this an empty section (the one at the end of the list)?
330 [2] = what is the 'post' value? (ident # or empty string if default)
331
332 You need to return any HTML you would like to add to the table.
333 You could add a table row with code similar to this:
334
335 function demo_identities_table(&$args)
336 {
337 return '<tr bgcolor="' . $args[0] . '"><td>&nbsp;</td><td>'
338 . 'YOUR CODE HERE' . '</td></tr>' . "\n";
339 }
340
341 options_identities_buttons
342
343 This hook allows you to add a button (or other HTML) to the row of
344 buttons under each identity. The arguments to this hook are:
345
346 [0] = is this an empty section (the one at the end of the list)?
347 [1] = what is the 'post' value? (ident # or empty string if default)
348
349 You need to return any HTML you would like to add here. You could add
350 a button with code similar to this:
351
352 function demo_identities_button(&$args)
353 {
354 return '<input type="submit" name="demo_button_' . $args[1]
355 . '" value="Press Me">';
356 }
357
358
359 (^) Attachment Hooks
360 --------------------
361 When a message has attachments, this hook is called with the MIME types. For
362 instance, a .zip file hook is "attachment application/x-zip". The hook should
363 probably show a link to do a specific action, such as "Verify" or "View" for a
364 .zip file. Thus, to register your plugin for .zip attachments, you'd do this
365 in setup.php (assuming your plugin is called "demo"):
366
367 $squirrelmail_plugin_hooks['attachment application/x-zip']['demo']
368 = 'demo_handle_zip_attachment';
369
370 This is a breakdown of the data passed in the array to the hook that is called:
371
372 [0] = Hook's name ('attachment text/plain')
373 [1] = Array of links of actions (see below) (alterable)
374 [2] = Used for returning to mail message (startMessage)
375 [3] = Used for finding message to display (id)
376 [4] = Mailbox name, urlencode()'d (urlMailbox)
377 [5] = Entity ID inside mail message (ent)
378 [6] = Default URL to go to when filename is clicked on (alterable)
379 [7] = Filename that is displayed for the attachment
380 [8] = Sent if message was found from a search (where)
381 [9] = Sent if message was found from a search (what)
382
383 To set up links for actions, you assign them like this:
384
385 $Args[1]['<plugin_name>']['href'] = 'URL to link to';
386 $Args[1]['<plugin_name>']['text'] = 'What to display';
387
388 It's also possible to specify a hook as "attachment type0/*",
389 for example "attachment text/*". This hook will be executed whenever there's
390 no more specific rule available for that type.
391
392 Putting all this together, the demo_handle_zip_attachment() function should
393 look like this (note the argument being passed):
394
395 function demo_handle_zip_attachment(&$Args)
396 {
397 include_once(SM_PATH . 'plugins/demo/functions.php');
398 demo_handle_zip_attachment_do($Args);
399 }
400
401 And the demo_handle_zip_attachment_do() function in the
402 plugins/demo/functions.php file would typically (but not necessarily)
403 display a custom link:
404
405 function demo_handle_zip_attachment_do(&$Args)
406 {
407 $Args[1]['demo']['href'] = SM_PATH . 'plugins/demo/zip_handler.php?'
408 . 'passed_id=' . $Args[3] . '&mailbox=' . $Args[4]
409 . '&passed_ent_id=' . $Args[5];
410 $Args[1]['demo']['text'] = 'show zip contents';
411 }
412
413 The file plugins/demo/zip_handler.php can now do whatever it needs with the
414 attachment (note that this will hand information about how to retrieve the
415 source message from the IMAP server as GET varibles).
416
417
418 (*) Options
419 -----------
420 Before you start adding user preferences to your plugin, please take a moment
421 to think about it: in some cases, more options may not be a good thing.
422 Having too many options can be confusing. Thinking from the user's
423 perspective, will the proposed options actually be used? Will users
424 understand what these options are for?
425
426 There are two ways to add options for your plugin. When you only have a few
427 options that don't merit an entirely new preferences page, you can incorporate
428 them into an existing section of SquirrelMail preferences (Personal
429 Information, Display Preferences, Message Highlighting, Folder Preferences or
430 Index Order). Or, if you have an extensive number of settings or for some
431 reason need a separate page for the user to interact with, you can create your
432 own preferences page.
433
434
435 Integrating Your Options Into Existing SquirrelMail Preferences Pages
436 ---------------------------------------------------------------------
437
438 There are two ways to accomplish the integration of your plugin's settings
439 into another preferences page. The first method is to add the HTML code
440 for your options directly to the preferences page of your choice. Although
441 currently very popular, this method will soon be deprecated, so avoid it
442 if you can. That said, here is how it works. :) Look for any of the hooks
443 named as "options_<pref page>_inside", where <pref page> is "display",
444 "personal", etc. For this example, we'll use "options_display_inside" and,
445 as above, "demo" as our plugin name:
446
447 1. In setup.php in the squirrelmail_plugin_init_demo() function:
448
449 $squirrelmail_plugin_hooks['options_display_inside']['demo']
450 = 'demo_show_options';
451
452 Note that there are also hooks such as "options_display_bottom",
453 however, they place your options at the bottom of the preferences
454 page, which is usually not desirable (mostly because they also
455 come AFTER the HTML FORM tag is already closed). It is possible
456 to use these hooks if you want to create your own FORM with custom
457 submission logic.
458
459 2. Assuming the function demo_show_options() calls another function
460 elsewhere called demo_show_options_do(), that function should have
461 output similar to this (note that you will be inserting code into
462 a table that is already defined with two columns, so please be sure
463 to keep this framework in your plugin):
464
465 ------cut here-------
466 <tr>
467 <td>
468 OPTION_NAME
469 </td>
470 <td>
471 OPTION_INPUT
472 </td>
473 </tr>
474 ------cut here-------
475
476 Of course, you can place any text where OPTION_NAME is and any input
477 tags where OPTION_INPUT is.
478
479 3. You will want to use the "options_<pref page>_save" hook (in this case,
480 "options_display_save") to save the user's settings after they have
481 pressed the "Submit" button. Again, back in setup.php in the
482 squirrelmail_plugin_init_demo() function:
483
484 $squirrelmail_plugin_hooks['options_display_save']['demo']
485 = 'demo_save_options';
486
487 4. Assuming the function demo_save_options() calls another function
488 elsewhere called demo_save_options_do(), that function should put
489 the user's settings into permanent storage (see the preferences
490 section below for more information). This example assumes that
491 in the preferences page, the INPUT tag's NAME attribute was set
492 to "demo_option":
493
494 global $data_dir, $username;
495 sqgetGlobalVar('demo_option', $demo_option);
496 setPref($data_dir, $username, 'demo_option', $demo_option);
497
498
499 The second way to add options to one of the SquirrelMail preferences page is
500 to use one of the "optpage_loadhook_<pref page>" hooks. The sent_subfolders
501 plugin is an excellent example of this method. Briefly, this way of adding
502 options consists of adding some plugin-specific information to a predefined
503 data structure which SquirrelMail then uses to build the HTML input forms
504 for you. This is the preferred method of building options lists going forward.
505
506 1. We'll use the "optpage_loadhook_display" hook to add a new group of
507 options to the display preferences page. In setup.php in the
508 squirrelmail_plugin_init_demo() function:
509
510 $squirrelmail_plugin_hooks['optpage_loadhook_display']['demo']
511 = 'demo_options';
512
513 2. Assuming the function demo_options() calls another function elsewhere
514 called demo_options_do(), that function needs to add a new key to two
515 arrays, $optpage_data['grps'] and $optpage_data['vals']. The value
516 associated with that key should simply be a section heading for your
517 plugin on the preferences page for the $optpage_data['grps'] array,
518 and yet another array with all of your plugin's options for the
519 $optpage_data['vals'] array. The options are built as arrays (yes,
520 that's four levels of nested arrays) that specify attributes that are
521 used by SquirrelMail to build your HTML input tags automatically.
522 This example includes just one input element, a SELECT (drop-down)
523 list:
524
525 global $optpage_data;
526 $optpage_data['grps']['DEMO_PLUGIN'] = 'Demo Options';
527 $optionValues = array();
528 $optionValues[] = array(
529 'name' => 'plugin_demo_favorite_color',
530 'caption' => 'Please Choose Your Favorite Color',
531 'type' => SMOPT_TYPE_STRLIST,
532 'refresh' => SMOPT_REFRESH_ALL,
533 'posvals' => array(0 => 'red',
534 1 => 'blue',
535 2 => 'green',
536 3 => 'orange'),
537 'save' => 'save_plugin_demo_favorite_color'
538 );
539 $optpage_data['vals']['DEMO_PLUGIN'] = $optionValues;
540
541 The array that you use to specify each plugin option has the following
542 possible attributes:
543
544 name The name of this setting, which is used not only for
545 the INPUT tag name, but also for the name of this
546 setting in the user's preferences
547 caption The text that prefaces this setting on the preferences page
548 type The type of INPUT element, which should be one of:
549 SMOPT_TYPE_STRING String/text input
550 SMOPT_TYPE_STRLIST Select list input
551 SMOPT_TYPE_TEXTAREA Text area input
552 SMOPT_TYPE_INTEGER Integer input
553 SMOPT_TYPE_FLOAT Floating point number input
554 SMOPT_TYPE_BOOLEAN Boolean (yes/no radio buttons)
555 input
556 SMOPT_TYPE_HIDDEN Hidden input (not actually shown
557 on preferences page)
558 SMOPT_TYPE_COMMENT Text is shown (specified by the
559 'comment' attribute), but no user
560 input is needed
561 SMOPT_TYPE_FLDRLIST Select list of IMAP folders
562 refresh Indicates if a link should be shown to refresh part or all
563 of the window (optional). Possible values are:
564 SMOPT_REFRESH_NONE No refresh link is shown
565 SMOPT_REFRESH_FOLDERLIST Link is shown to refresh
566 only the folder list
567 SMOPT_REFRESH_ALL Link is shown to refresh
568 the entire window
569 posvals For select lists, this should be an associative array,
570 where each key is an actual input value and the
571 corresponding value is what is displayed to the user
572 for that list item in the drop-down list
573 value Specify the default/preselected value for this option input
574 save You may indicate that special functionality needs to be
575 used instead of just saving this setting by giving the
576 name of a function to call when this value would otherwise
577 just be saved in the user's preferences
578 size Specifies the size of certain input items (typically
579 textual inputs). Possible values are:
580 SMOPT_SIZE_TINY
581 SMOPT_SIZE_SMALL
582 SMOPT_SIZE_MEDIUM
583 SMOPT_SIZE_LARGE
584 SMOPT_SIZE_HUGE
585 SMOPT_SIZE_NORMAL
586 comment For SMOPT_TYPE_COMMENT type options, this is the text
587 displayed to the user
588 script This is where you may add any additional javascript
589 or other code to the user input
590
591 3. If you indicated a 'save' attribute for any of your options, you must
592 create that function (you'll only need to do this if you need to do
593 some special processing for one of your settings). The function gets
594 one parameter, which is an object with mostly the same attributes you
595 defined when you made the option above... the 'new_value' (and possibly
596 'value', which is the current value for this setting) is the most useful
597 attribute in this context:
598
599 function save_plugin_demo_favorite_color($option)
600 {
601 // if user chose orange, make note that they are really dumb
602 if ($option->new_value == 3)
603 {
604 // more code here as needed
605 }
606
607 // don't even save this setting if user chose green (old
608 // setting will remain)
609 if ($option->new_value == 2)
610 return;
611
612 // for all other colors, save as normal
613 save_option($option);
614 }
615
616
617 Creating Your Own Preferences Page
618 ----------------------------------
619
620 It is also possible to create your own preferences page for a plugin. This
621 is particularly useful when your plugin has numerous options or needs to
622 offer special interaction with the user (for things such as changing password,
623 etc.). Here is an outline of how to do so (again, using the "demo" plugin
624 name):
625
626 1. Add a new listing to the main Options page. Older versions of
627 SquirrelMail offered a hook called "options_link_and_description"
628 although its use is deprecated (and it is harder to use in that
629 it requires you to write your own HTML to add the option). Instead,
630 you should always use the "optpage_register_block" hook where you
631 create a simple array that lets SquirrelMail build the HTML
632 to add the plugin options entry automatically. In setup.php in the
633 squirrelmail_plugin_init_demo() function:
634
635 $squirrelmail_plugin_hooks['optpage_register_block']['demo']
636 = 'demo_options_block';
637
638 2. Assuming the function demo_options_block() calls another function
639 elsewhere called demo_options_block_do(), that function only needs
640 to create a simple array and add it to the $optpage_blocks array:
641
642 global $optpage_blocks;
643 $optpage_blocks[] = array(
644 'name' => 'Favorite Color Settings',
645 'url' => SM_PATH . 'plugins/demo/options.php',
646 'desc' => 'Change your favorite color & find new exciting colors',
647 'js' => FALSE
648 );
649
650 The array should have four elements:
651 name The title of the plugin's options as it will be displayed on
652 the Options page
653 url The URI that points to your plugin's custom preferences page
654 desc A description of what the preferences page offers the user,
655 displayed on the Options page below the title
656 js Indicates if this option page requires the client browser
657 to be Javascript-capable. Should be TRUE or FALSE.
658
659 3. There are two different ways to create the actual preferences page
660 itself. One is to simply write all of your own HTML and other
661 interactive functionality, while the other is to define some data
662 structures that allow SquirrelMail to build your user inputs and save
663 your data automatically.
664
665 Building your own page is wide open, and for ideas, you should look at
666 any of the plugins that currently have their own preferences pages. If
667 you do this, make sure to read step number 4 below for information on
668 saving settings. In order to maintain security, consistant look and
669 feel, internationalization support and overall integrity, there are just
670 a few things you should always do in this case: define the SM_PATH
671 constant, include the file include/validate.php (see the section about
672 including other files above) and make a call to place the standard page
673 heading at the top of your preferences page. The top of your PHP file
674 might look something like this:
675
676 define('SM_PATH', '../../');
677 include_once(SM_PATH . 'include/validate.php');
678 global $color;
679 displayPageHeader($color, 'None');
680
681 From here you are on your own, although you are encouraged to do things
682 such as use the $color array to keep your HTML correctly themed, etc.
683
684 If you want SquirrelMail to build your preferences page for you,
685 creating input forms and automatically saving users' settings, then
686 you should change the 'url' attribute in the options block you created
687 in step number 2 above to read as follows:
688
689 'url' => SM_PATH . 'src/options.php?optpage=plugin_demo',
690
691 Now, you will need to use the "optpage_set_loadinfo" hook to tell
692 SquirrelMail about your new preferences page. In setup.php in the
693 squirrelmail_plugin_init_demo() function:
694
695 $squirrelmail_plugin_hooks['optpage_set_loadinfo']['demo']
696 = 'demo_optpage_loadinfo';
697
698 Assuming the function demo_optpage_loadinfo() calls another function
699 elsewhere called demo_optpage_loadinfo_do(), that function needs to
700 define values for four variables (make sure you test to see that it
701 is your plugin that is being called by checking the GET variable you
702 added to the url just above):
703
704 global $optpage, $optpage_name, $optpage_file,
705 $optpage_loader, $optpage_loadhook;
706 if ($optpage == 'plugin_demo')
707 {
708 $optpage_name = "Favorite Color Preferences";
709 $optpage_file = SM_PATH . 'plugins/demo/options.php';
710 $optpage_loader = 'load_optpage_data_demo';
711 $optpage_loadhook = 'optpage_loadhook_demo';
712 }
713
714 Now you are ready to build all of your options. In the file you
715 indicated for the variable $optpage_file above, you'll need to create
716 a function named the same as the value you used for $optpage_loader
717 above. In this example, the file plugins/demo/options.php should
718 have at least this function in it:
719
720 function load_optpage_data_demo()
721 {
722 $optpage_data = array();
723 $optpage_data['grps']['DEMO_PLUGIN'] = 'Demo Options';
724 $optionValues = array();
725 $optionValues[] = array(
726 'name' => 'plugin_demo_favorite_color',
727 'caption' => 'Please Choose Your Favorite Color',
728 'type' => SMOPT_TYPE_STRLIST,
729 'refresh' => SMOPT_REFRESH_ALL,
730 'posvals' => array(0 => 'red',
731 1 => 'blue',
732 2 => 'green',
733 3 => 'orange'),
734 'save' => 'save_plugin_demo_favorite_color'
735 );
736 $optpage_data['vals']['DEMO_PLUGIN'] = $optionValues;
737 return $optpage_data;
738 }
739
740 For a detailed description of how you build these options, please read
741 step number 2 for the second method of adding options to an existing
742 preferences page above. Notice that the only difference here is in the
743 very first and last lines of this function where you are actually
744 creating and returning the options array instead of just adding onto it.
745
746 That's all there is to it - SquirrelMail will create a preferences page
747 titled as you indicated for $optpage_name above, and other plugins
748 can even add extra options to this new preferences page. To do so,
749 they should use the hook name you specified for $optpage_loadhook above
750 and use the second method for adding option settings to existing
751 preferences pages described above.
752
753 4. Saving your options settings: if you used the second method in step
754 number 3 above, your settings will be saved automatically (or you can
755 define special functions to save special settings such as the
756 save_plugin_demo_favorite_color() function in the example described
757 above) and there is probably no need to follow this step. If you
758 created your own preferences page from scratch, you'll need to follow
759 this step. First, you need to register your plugin against the
760 "options_save" hook. In setup.php in the squirrelmail_plugin_init_demo()
761 function:
762
763 $squirrelmail_plugin_hooks['options_save']['demo']
764 = 'demo_save_options';
765
766 Assuming the function demo_save_options() calls another function
767 elsewhere called demo_save_options_do(), that function needs to grab
768 all of your POST and/or GET settings values and save them in the user's
769 preferences (for more about preferences, see that section below). Since
770 this is a generic hook called for all custom preferences pages, you
771 should always set "optpage" as a POST or GET variable with a string that
772 uniquely identifies your plugin:
773
774 <input type="hidden" name="optpage" value="plugin_demo">
775
776 Now in your demo_save_options_do() function, do something like this:
777
778 global $username, $data_dir, $optpage, $favorite_color;
779 if ($optpage == 'plugin_demo')
780 {
781 sqgetGlobalVar('favorite_color', $favorite_color, SQ_FORM);
782 setPref($data_dir, $username, 'favorite_color', $favorite_color);
783 }
784
785 Note that $favorite_color may not need to be globalized, although
786 experience has shown that some versions of PHP don't behave as expected
787 unless you do so. Even when you use SquirrelMail's built-in preferences
788 page generation functionality, you may still use this hook, although
789 there should be no need to do so. If you need to do some complex
790 validation routines, note that it might be better to do so in the file
791 you specified as the "$optpage_file" (in our example, that was the
792 plugins/demo/options.php file), since at this point, you can still
793 redisplay your preferences page. You could put code similar to this
794 in the plugins/demp/options.php file (note that there is no function;
795 this code needs to be executed at include time):
796
797 global $optmode;
798 if ($optmode == 'submit')
799 {
800 // do something here such as validation, etc
801 if (you want to redisplay your preferences page)
802 $optmode = '';
803 }
804
805
806 Preferences
807 -----------
808
809 Saving and retrieving user preferences is very easy in SquirrelMail.
810 SquirrelMail supports preference storage in files or in a database
811 backend, however, the code you need to write to manipulate preferences
812 is the same in both cases.
813
814 Setting preferences:
815
816 Setting preferences is done for you if you use the built-in facilities
817 for automatic options construction and presentation (see above). If
818 you need to manually set preferences, however, all you need to do is:
819
820 global $data_dir, $username;
821 setPref($data_dir, $username, 'pref_name', $pref_value);
822
823 Where "pref_name" is the key under which the value will be stored
824 and "pref_value" is a variable that should contain the actual
825 preference value to be stored.
826
827 Loading preferences:
828
829 There are two approaches to retrieving plugin (or any other) preferences.
830 You can grab individual preferences one at a time or you can add your
831 plugin's preferences to the routine that loads up user preferences at
832 the beginning of each page request. If you do the latter, making sure
833 to place your preference variables into the global scope, they will be
834 immediately available in all other plugin code. To retrieve a single
835 preference value at any time, do this:
836
837 global $data_dir, $username;
838 $pref_value = getPref($data_dir, $username, 'pref_name', 'default value');
839
840 Where "pref_name" is the preference you are retrieving, "default_value"
841 is what will be returned if the preference is not found for this user,
842 and, of course, "pref_value" is the variable that will get the actual
843 preference value.
844
845 To have all your preferences loaded at once when each page request is
846 made, you'll need to register a function against the "loading_prefs" hook.
847 For our "demo" plugin, in setup.php in the squirrelmail_plugin_init_demo()
848 function:
849
850 $squirrelmail_plugin_hooks['loading_prefs']['demo']
851 = 'demo_load_prefs';
852
853 Assuming the function demo_load_prefs() calls another function
854 elsewhere called demo_load_prefs_do(), that function just needs to
855 pull out any all all preferences you'll be needing elsewhere:
856
857 global $data_dir, $username, $pref_value;
858 $pref_value = getPref($data_dir, $username, 'pref_name', 'default value');
859
860 Remember to globalize each preference, or this code is useless.
861
862
863 Internationalization
864 --------------------
865
866 Although this document may only be available in English, we sure hope that you
867 are thinking about making your plugin useful to the thousands of non-English
868 speaking SquirrelMail users out there! It is almost rude not to do so, and
869 it isn't much trouble, either. This document will only describe how you can
870 accomplish the internationalization of a plugin. For more general information
871 about PHP and SquirrelMail translation facilities, see:
872
873 http://www.squirrelmail.org/wiki/wiki.php?LanguageTranslation
874
875 The unofficial way to internationalize a plugin is to put all plugin output
876 into the proper format but to rely on the SquirrelMail translation facilities
877 for all the rest. If the plugin were really to get translated, you'd need
878 to make sure that all output strings for your plugin are either added to or
879 already exist in the main SquirrelMail locale files.
880
881 The better way to make sure your plugin is translated is to create your own
882 locale files and what is called a "gettext domain" (see the link above for
883 more information).
884
885 There are three basic steps to getting your plugins internationalized: put
886 all output into the proper format, switch gettext domains and create locale
887 files.
888
889 1. Putting plugin output into the correct format is quite easy. The hard
890 part is making sure you catch every last echo statement. You need to
891 echo text like this:
892
893 echo _("Hello");
894
895 So, even in the HTML segments of your plugin files, you need to do this:
896
897 <input type="submit" value="<?php echo _("Submit") ?>">
898
899 You can put any text you want inside of the quotes (you MUST use double
900 quotes!), including HTML tags, etc. What you should think carefully
901 about is that some languages may use different word ordering, so this
902 might be problematic:
903
904 echo _("I want to eat a ") . $fruitName . _(" before noon");
905
906 Because some languages (Japanese, for instance) would need to translate
907 such a sentence to "Before noon " . $fruitName . " I want to eat", but
908 with the format above, they are stuck having to translate each piece
909 separately. You might want to reword your original sentence:
910
911 echo _("This is what I want to eat before noon: ") . $fruitName;
912
913 2. By default, the SquirrelMail gettext domain is always in use. That
914 means that any text in the format described above will be translated
915 using the locale files found in the main SquirrelMail locale directory.
916 Unless your plugin produces no output or only output that is in fact
917 translated under the default SquirrelMail domain, you need to create
918 your own gettext domain. The PHP for doing so is very simple. At
919 the top of any file that produces any output, place the following code
920 (again, using "demo" as the plugin name):
921
922 bindtextdomain('demo', SM_PATH . 'plugins/demo/locale');
923 textdomain('demo');
924
925 Now all output will be translated using your own custom locale files.
926 Please be sure to switch back to the SquirrelMail domain at the end
927 of the file, or many of the other SquirrelMail files may misbehave:
928
929 bindtextdomain('squirrelmail', SM_PATH . 'locale');
930 textdomain('squirrelmail');
931
932 Note that if, in the middle of your plugin file, you use any
933 SquirrelMail functions that send output to the browser, you'll need
934 to temporarily switch back to the SquirrelMail domain:
935
936 bindtextdomain('squirrelmail', SM_PATH . 'locale');
937 textdomain('squirrelmail');
938 displayPageHeader($color, 'None');
939 bindtextdomain('demo', SM_PATH . 'plugins/demo/locale');
940 textdomain('demo');
941
942 Note that technically speaking, you only need to have one bindtextdomain
943 call per file, you should always use it before every textdomain call,
944 since PHP installations without gettext compiled into them will not
945 function properly if you do not.
946
947 3. Finally, you just need to create your own locale. You should create
948 a directory structure like this in the plugin directory:
949
950 demo
951 |
952 ------locale
953 |
954 ------de_DE
955 | |
956 | ------LC_MESSAGES
957 |
958 ------ja_JP
959 |
960 ------LC_MESSAGES
961
962 Create a directories such as de_DE for each language (de_DE is German,
963 ja_JP is Japanese, etc. - check the SquirrelMail locale directory for
964 a fairly comprehensive listing). Inside of each LC_MESSAGES directory
965 you should place two files, one with your translations in it, called
966 <plugin name>.po (in this case, "demo.po"), and one that is a compiled
967 version of the ".po" file, called <plugin name>.mo (in this case,
968 "demo.mo"). On most linux systems, there is a tool you can use to pull
969 out most of the strings that you need to have translated from your PHP
970 files into a sample .po file:
971
972 xgettext --keyword=_ -d <plugin name> -s -C *.php
973
974 --keyword option tells xgettext what your strings are enclosed in
975 -d is the domain of your plugin which should be the plugin's name
976 -s tells xgettext to sort the results and remove duplicate strings
977 -C means you are translating a file with C/C++ type syntax (ie. PHP)
978 *.php is all the files you want translations for
979
980 Note, however, that this will not always pick up all strings, so you
981 should double-check manually. Of course, it's easiest if you just keep
982 track of all your strings as you are coding your plugin. Your .po file
983 will now look something like:
984
985 # SOME DESCRIPTIVE TITLE.
986 # Copyright (C) YEAR Free Software Foundation, Inc.
987 # FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
988 #
989 #, fuzzy
990 msgid ""
991 msgstr ""
992 "Project-Id-Version: PACKAGE VERSION\n"
993 "POT-Creation-Date: 2003-06-18 11:22-0600\n"
994 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
995 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
996 "Language-Team: LANGUAGE <LL@li.org>\n"
997 "MIME-Version: 1.0\n"
998 "Content-Type: text/plain; charset=CHARSET\n"
999 "Content-Transfer-Encoding: ENCODING\n"
1000
1001 #: functions.php:45
1002 msgid "Hello"
1003 msgstr ""
1004
1005 #: functions.php:87
1006 msgid "Favorite Color"
1007 msgstr ""
1008
1009 You should change the header to look something more like:
1010
1011 # Copyright (c) 1999-2003 The Squirrelmail Development Team
1012 # Roland Bauerschmidt <rb@debian.org>, 1999.
1013 msgid ""
1014 msgstr ""
1015 "Project-Id-Version: $Id: squirrelmail.po,v 1.10 2003/06/04 15:01:59
1016 philippe_mingo Exp $\n"
1017 "POT-Creation-Date: 2003-01-21 19:21+0100\n"
1018 "PO-Revision-Date: 2003-01-21 21:01+0100\n"
1019 "Last-Translator: Juergen Edner <juergen.edner@epost.de>\n"
1020 "Language-Team: German <squirrelmail-i18n@lists.squirrelmail.net>\n"
1021 "MIME-Version: 1.0\n"
1022 "Content-Type: text/plain; charset=ISO-8859-1\n"
1023 "Content-Transfer-Encoding: 8bit\n"
1024
1025 The most important thing to change here is the charset on the next to
1026 last line. You'll want to keep a master copy of the .po file and make
1027 a copy for each language you have a translation for. You'll need to
1028 translate each string in the .po file:
1029
1030 msgid "Hello"
1031 msgstr "Guten Tag"
1032
1033 After you're done translating, you can create the .mo file very simply
1034 by running the following command (available on most linux systems):
1035
1036 msgfmt -0 <plugin name>.mo <plugin name>.po
1037
1038 In the case of the "demo" plugin:
1039
1040 msgfmt -0 demo.mo demo.po
1041
1042 Please be sure that the .po and .mo files both are named exactly the
1043 same as the domain you bound in step 2 above and everything else works
1044 automatically. In SquirrelMail, go to Options -> Display Preferences
1045 and change your Language setting to see the translations in action!
1046
1047
1048 PLUGIN STANDARDS AND REQUIREMENTS
1049 =================================
1050
1051 The SquirrelMail project has some important goals, such as avoiding the
1052 use of JavaScript, avoiding non-standard HTML tags, keeping file sizes
1053 small and providing the fastest webmail client on the Internet. As such,
1054 we'd like it if plugin authors coded with the same goals in mind that the
1055 core developers do. Common sense is always a good tool to have in your
1056 programming repertoire, but below is an outline of some standards that we
1057 ask you as a plugin developer to meet. Depending upon how far you bend
1058 these rules, we may not want to post your plugin on the SquirrelMail
1059 website... and of course, no one really wants your efforts to go to waste
1060 and for the SquirrelMail community to miss out on a potentially useful
1061 plugin, so please try to follow these guidelines as closely as possible.
1062
1063
1064 Small setup.php
1065 ---------------
1066
1067 In order for SquirrelMail to remain fast and lean, we are now asking
1068 that all plugin authors remove all unnecessary functionality from setup.php
1069 and refactoring it into another file. There are a few ways to accomplish
1070 this, none of which are difficult. At a minimum, you'll want to have the
1071 squirrelmail_plugin_init_<plugin name>() function in setup.php, and naturally,
1072 you'll need functions that are merely stubs for each hook that you are using.
1073 One (but not the only) way to do it is:
1074
1075 function squirrelmail_plugin_init_demo()
1076 {
1077 global $squirrelmail_plugin_hooks;
1078 $squirrelmail_plugin_hooks['generic_header']['demo'] = 'plugin_demo_header';
1079 }
1080 function plugin_demo_header()
1081 {
1082 include_once(SM_PATH . 'plugins/demo/functions.php');
1083 plugin_demo_header_do();
1084 }
1085
1086
1087 Internationalization
1088 --------------------
1089
1090 Q: What is more disappointing to users in France who would make good
1091 use of your plugin than learning that it is written entirely in English?
1092 A: Learning that they cannot send you a French translation file for your
1093 plugin.
1094
1095 There are thousands of users out there whose native tongue is not English,
1096 and when you develop your plugin without going through the three simple steps
1097 needed to internationalize it, you are effectively writing them all off.
1098 PLEASE consider internationalizing your plugin!
1099
1100
1101 Developing with E_ALL
1102 ---------------------
1103
1104 When you are developing your plugin, you should always have error reporting
1105 turned all the way up. You can do this by changing two settings in your
1106 php.ini and restarting your web server:
1107
1108 display_errors = Off
1109 error_reporting = E_ALL
1110
1111 This way, you'll be sure to see all Notices, Warnings and Errors that your
1112 code generates (it's OK, really, it happens to the best of us... except me!).
1113 Please make sure to fix them all before you release the plugin.
1114
1115
1116 Extra Blank Lines
1117 -----------------
1118
1119 It may seem innocuous, but if you have any blank lines either before the
1120 first <?php tag or after the last ?> tag in any of your plugin files, you
1121 you will break SquirrelMail in ways that may seem entirely unrelated. For
1122 instance, this will often cause a line feed character to be included with
1123 email attachments when they are viewed or downloaded, rendering them useless!
1124
1125
1126 include_once
1127 ------------
1128
1129 When including files, please make sure to use the include_once() function
1130 and NOT include(), require(), or require_once(), since these all are much
1131 less efficient than include_once() and can have a cumulative effect on
1132 SquirrelMail performance.
1133
1134
1135 Version Reporting
1136 -----------------
1137
1138 In order for systems administrators to keep better track of your plugin and
1139 get upgrades more efficiently, you are requested to make version information
1140 available to SquirrelMail in a format that it understands. There are two
1141 ways to do this. Presently, we are asking that you do both, since we are
1142 still in a transition period between the two. This is painless, so please
1143 be sure to include it:
1144
1145 1. Create a file called "version" in the plugin directory. That file
1146 should have only two lines: the first line should have the name of
1147 the plugin as named on the SquirrelMail web site (this is often a
1148 prettified version of the plugin directory name), the second line
1149 must have the version and nothing more. So for our "demo" plugin,
1150 whose name on the web site might be something like "Demo Favorite
1151 Colors", the file plugins/demo/version should have these two lines:
1152
1153 Demo Favorite Colors
1154 1.0
1155
1156 2. In setup.php, you should have a function called <plugin name>_version().
1157 That function should return the version of your plugin. For the "demo"
1158 plugin, that should look like this:
1159
1160 function demo_version()
1161 {
1162 return '1.0';
1163 }
1164
1165
1166 Configuration Files
1167 -------------------
1168
1169 It is common to need a configuration file that holds some variables that
1170 are set up at install time. For ease of installation and maintenance, you
1171 should place all behavioral settings in a config file, isolated from the
1172 rest of your plugin code. A typical file name to use is "config.php". If
1173 you are using such a file, you should NOT include a file called "config.php"
1174 in your plugin distribution, but instead a copy of that file called
1175 "config.php.sample". This helps systems administrators avoid overwriting
1176 the "config.php" files and losing all of their setup information when they
1177 upgrade your plugin.
1178
1179
1180 Session Variables
1181 -----------------
1182
1183 In the past, there have been some rather serious issues with PHP sessions
1184 and SquirrelMail, and certain people have worked long and hard to ensure
1185 that these problems no longer occur in an extremely wide variety of OS/PHP/
1186 web server environments. Thus, if you need to place any values into the
1187 user's session, there are some built-in SquirrelMail functions that you are
1188 strongly encouraged to make use of. Using them also makes your job easier.
1189
1190 1. To place a variable into the session:
1191
1192 global $favorite_color;
1193 $favoriteColor = 'green';
1194 sqsession_register($favorite_color, 'favorite_color');
1195
1196 Strictly speaking, globalizing the variable shouldn't be necessary,
1197 but certain versions of PHP seem to behave more predictably if you do.
1198
1199 2. To retrieve a variable from the session:
1200
1201 global $favorite_color;
1202 sqgetGlobalVar('favorite_color', $favorite_color, SQ_SESSION);
1203
1204 3. You can also check for the presence of a variable in the session:
1205
1206 if (sqsession_is_registered('favorite_color'))
1207 // do something important
1208
1209 4. To remove a variable from the session:
1210
1211 global $favorite_color;
1212 sqsession_unregister('favorite_color');
1213
1214 Strictly speaking, globalizing the variable shouldn't be necessary,
1215 but certain versions of PHP seem to behave more predictably if you do.
1216
1217
1218 Form Variables
1219 --------------
1220
1221 You are also encouraged to use SquirrelMail's built-in facilities to
1222 retrieve variables from POST and GET submissions. This is also much
1223 easier on you and makes sure that all PHP installations are accounted
1224 for (such as those that don't make the $_POST array automatically
1225 global, etc.):
1226
1227 global $favorite_color;
1228 sqgetGlobalVar('favorite_color', $favorite_color, SQ_FORM);
1229
1230
1231 Files In Plugin Directory
1232 -------------------------
1233
1234 There are a few files that you should make sure to include when you build
1235 your final plugin distribution:
1236
1237 1. A copy of the file index.php from the main plugins directory. When
1238 working in your plugin directory, just copy it in like this:
1239
1240 $ cp ../index.php .
1241
1242 This will redirect anyone who tries to browse to your plugin directory
1243 to somewhere more appropriate. If you create other directories under
1244 your plugin directory, you may copy the file there as well to be extra
1245 safe. If you are storing sensitive configuration files or other data
1246 in such a directory, you could even include a .htaccess file with the
1247 contents "Deny From All" that will disallow access to that directory
1248 entirely (when the target system is running the Apache web server).
1249 Keep in mind that not all web servers will honor an .htaccess file, so
1250 don't depend on it for security. Make sure not to put such a file in
1251 your main plugin directory!
1252
1253 2. A file that describes your plugin and offers detailed instructions for
1254 configuration or help with troubleshooting, etc. This file is usually
1255 entitled "README". Some useful sections to include might be:
1256
1257 Plugin Name and Author
1258 Current Version
1259 Plugin Features
1260 Detailed Plugin Description
1261 How-to for Plugin Configuration
1262 Change Log
1263 Future Ideas/Enhancements/To Do List
1264
1265 3. A file that explains how to install your plugin. This file is typically
1266 called "INSTALL". If you do not require any special installation
1267 actions, you can probably copy one from another plugin or use this as
1268 a template:
1269
1270 Installing the Demo Plugin
1271 ==========================
1272
1273 1) Start with untaring the file into the plugins directory.
1274 Here is a example for the 1.0 version of the Demo plugin.
1275
1276 $ cd plugins
1277 $ tar -zxvf demo-1.0-1.4.0.tar.gz
1278
1279 2) Change into the demo directory, copy config.php.sample
1280 to config.php and edit config.php, making adjustments as
1281 you deem necessary. For more detailed explanations about
1282 each of these parameters, consult the README file.
1283
1284 $ cd demo
1285 $ cp config.php.sample config.php
1286 $ vi config.php
1287
1288
1289 3) Then go to your config directory and run conf.pl. Choose
1290 option 8 and move the plugin from the "Available Plugins"
1291 category to the "Installed Plugins" category. Save and exit.
1292
1293 $ cd ../../config/
1294 $ ./conf.pl
1295
1296
1297 Upgrading the Demo Plugin
1298 =========================
1299
1300 1) Start with untaring the file into the plugins directory.
1301 Here is a example for the 3.1 version of the demo plugin.
1302
1303 $ cd plugins
1304 $ tar -zxvf demo-3.1-1.4.0.tar.gz
1305
1306
1307 2) Change into the demo directory, check your config.php
1308 file against the new version, to see if there are any new
1309 settings that you must add to your config.php file.
1310
1311 $ diff -Nau config.php config.php.sample
1312
1313 Or simply replace your config.php file with the provided sample
1314 and reconfigure the plugin from scratch (see step 2 under the
1315 installation procedure above).
1316
1317
1318 COMPATIBILITY WITH OLDER VERSIONS OF SQUIRRELMAIL
1319 =================================================
1320
1321 Whenever new versions of SquirrelMail are released, there is always a
1322 considerable lag time before it is widely adopted. During that transitional
1323 time, especially when the new SquirrelMail version contains any architectural
1324 and/or functional changes, plugin developers are put in a unique and very
1325 difficult position. That is, there will be people running both the old and
1326 new versions of SquirrelMail who want to use your plugin, and you will
1327 probably want to accomodate them both.
1328
1329 The easiest way to keep both sides happy is to keep two different versions
1330 of your pluign up to date, one that runs under the older SquirrelMail, and
1331 one that requires the newest SquirrelMail. This is inconvenient, however,
1332 especially if you are continuing to develop the plugin. Depending on the
1333 changes the SquirrelMail has implemented in the new version, you may be able
1334 to include code that can auto-sense SquirrelMail version and make adjustments
1335 on the fly. There is a function available to you for determining the
1336 SquirrelMail version called check_sm_version() and it can be used as such:
1337
1338 check_sm_version(1, 4, 0)
1339
1340 This will return TRUE if the SquirrelMail being used is at least 1.4.0, and
1341 FALSE otherwise.
1342
1343 As this document is written, we are in a transition period between versions
1344 1.2.11 and 1.4.0. There is a plugin called "Compatibilty" that is intended
1345 for use by plugin authors so they can develop one version of their plugin
1346 and seamlessly support both 1.2.x and 1.4.x SquirrelMail installations. For
1347 more information about how to use the "Compatibility" plugin, download it and
1348 read its README file or see:
1349
1350 http://www.squirrelmail.org/wiki/wiki.php?PluginUpgrading
1351
1352
1353 REQUESTING NEW HOOKS
1354 ====================
1355
1356 It's impossible to foresee all of the places where hooks might be useful
1357 (it's also impossible to put in hooks everywhere!), so you might need to
1358 negotiate the insertion of a new hook to make your plugin work. In order
1359 to do so, you should post such a request to the squirrelmail-devel mailing
1360 list.
1361
1362
1363 HOW TO RELEASE YOUR PLUGIN
1364 ==========================
1365
1366 As long as you've consulted the list of plugin standards and done your
1367 best to follow them, there's little standing in the way of great fame as an
1368 official SquirrelMail plugin developer.
1369
1370 1. Make a distribution file. There is a convenient Perl script in
1371 the plugins directory that will help you do this:
1372
1373 make_archive.pl -v demo 1.0 1.4.0
1374
1375 -v is optional and indicates that the script should run in verbose mode
1376 demo is the name of your plugin
1377 1.0 is the version of your plugin
1378 1.4.0 is the version of SquirrelMail that is required to run your plugin
1379
1380 You can also create the distribution file manually in most *nix
1381 environments by running this command from the plugins directory (NOT
1382 your plugin directory):
1383
1384 $ tar czvf demo-1.0-1.4.0.tar.gz demo
1385
1386 Where "demo" is the name of your plugin, "1.0" is the version of
1387 your plugin, and "1.4.0" is the version of SquirrelMail required
1388 to use your plugin.
1389
1390 2. Consult the SquirrelMail web site for contact information for the
1391 Plugins Team Leaders, to whom you should make your request. If they
1392 do not respond, you should feel free to ask for help contacting them
1393 on the squirrelmail-plugins mailing list.
1394
1395 http://www.squirrelmail.org/wiki/wiki.php?SquirrelMailLeadership
1396