system.api.php 120 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
<?php
// $Id$

/**
 * @file
 * Hooks provided by Drupal core and the System module.
 */

/**
 * @addtogroup hooks
 * @{
 */

14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
/**
 * Defines one or more hooks that are exposed by a module.
 *
 * Normally hooks do not need to be explicitly defined. However, by declaring a
 * hook explicitly, a module may define a "group" for it. Modules that implement
 * a hook may then place their implementation in either $module.module or in
 * $module.$group.inc. If the hook is located in $module.$group.inc, then that
 * file will be automatically loaded when needed.
 * In general, hooks that are rarely invoked and/or are very large should be
 * placed in a separate include file, while hooks that are very short or very
 * frequently called should be left in the main module file so that they are
 * always available.
 *
 * @return
 *   An associative array whose keys are hook names and whose values are an
 *   associative array containing:
 *   - group: A string defining the group to which the hook belongs. The module
 *     system will determine whether a file with the name $module.$group.inc
 *     exists, and automatically load it when required.
 *
 * See system_hook_info() for all hook groups defined by Drupal core.
 */
function hook_hook_info() {
  $hooks['token_info'] = array(
    'group' => 'tokens',
  );
  $hooks['tokens'] = array(
    'group' => 'tokens',
  );
  return $hooks;
}

46
47
48
49
50
51
52
53
54
55
56
57
/**
 * Inform the base system and the Field API about one or more entity types.
 *
 * Inform the system about one or more entity types (i.e., object types that
 * can be loaded via entity_load() and, optionally, to which fields can be
 * attached).
 *
 * @see entity_load()
 * @see hook_entity_info_alter()
 *
 * @return
 *   An array whose keys are entity type names and whose values identify
58
 *   properties of those types that the system needs to know about:
59
 *   - label: The human-readable name of the type.
60
 *   - controller class: The name of the class that is used to load the objects.
61
 *     The class has to implement the DrupalEntityControllerInterface interface.
62
63
 *     Leave blank to use the DrupalDefaultEntityController implementation.
 *   - base table: (used by DrupalDefaultEntityController) The name of the
64
 *     entity type's base table.
65
 *   - static cache: (used by DrupalDefaultEntityController) FALSE to disable
66
 *     static caching of entities during a page request. Defaults to TRUE.
67
68
 *   - load hook: The name of the hook which should be invoked by
 *     DrupalDefaultEntityController:attachLoad(), for example 'node_load'.
69
70
71
 *   - uri callback: A function taking an entity as argument and returning the
 *     uri elements of the entity, e.g. 'path' and 'options'. The actual entity
 *     uri can be constructed by passing these elements to url().
72
 *   - fieldable: Set to TRUE if you want your entity type to be fieldable.
73
 *   - object keys: An array describing how the Field API can extract the
74
 *     information it needs from the objects of the type. Elements:
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
 *     - id: The name of the property that contains the primary id of the
 *       object. Every object passed to the Field API must have this property
 *       and its value must be numeric.
 *     - revision: The name of the property that contains the revision id of
 *       the object. The Field API assumes that all revision ids are unique
 *       across all objects of a type.
 *       This element can be omitted if the objects of this type are not
 *       versionable.
 *     - bundle: The name of the property that contains the bundle name for the
 *       object. The bundle name defines which set of fields are attached to
 *       the object (e.g. what nodes call "content type").
 *       This element can be omitted if this type has no bundles (all objects
 *       have the same fields).
 *   - bundle keys: An array describing how the Field API can extract the
 *     information it needs from the bundle objects for this type (e.g
 *     $vocabulary objects for terms; not applicable for nodes).
 *     This element can be omitted if this type's bundles do not exist as
92
 *     standalone objects. Elements:
93
94
95
96
97
98
99
 *     - bundle: The name of the property that contains the name of the bundle
 *       object.
 *   - cacheable: A boolean indicating whether Field API should cache
 *     loaded fields for each object, reducing the cost of
 *     field_attach_load().
 *   - bundles: An array describing all bundles for this object type.
 *     Keys are bundles machine names, as found in the objects' 'bundle'
100
 *     property (defined in the 'object keys' entry above). Elements:
101
 *     - label: The human-readable name of the bundle.
102
103
 *     - admin: An array of information that allows Field UI pages to attach
 *       themselves to the existing administration pages for the bundle.
104
 *       Elements:
105
106
107
108
109
110
111
112
113
114
 *       - path: the path of the bundle's main administration page, as defined
 *         in hook_menu(). If the path includes a placeholder for the bundle,
 *         the 'bundle argument', 'bundle helper' and 'real path' keys below
 *         are required.
 *       - bundle argument: The position of the placeholder in 'path', if any.
 *       - real path: The actual path (no placeholder) of the bundle's main
 *         administration page. This will be used to generate links.
 *       - access callback: As in hook_menu(). 'user_access' will be assumed if
 *         no value is provided.
 *       - access arguments: As in hook_menu().
115
116
117
118
119
120
121
122
123
 *   - view modes: An array describing the view modes for the entity type. View
 *     modes let entities be displayed differently depending on the context.
 *     For instance, a node can be displayed differently on its own page
 *     ('full' mode), on the home page or taxonomy listings ('teaser' mode), or
 *     in an RSS feed ('rss' mode). Modules taking part in the display of the
 *     entity (notably the Field API) can adjust their behavior depending on
 *     the requested view mode. Keys of the array are view mode names. Each
 *     view mode is described by an array with the following key/value pairs:
 *     - label: The human-readable name of the view mode
124
125
126
127
 */
function hook_entity_info() {
  $return = array(
    'node' => array(
128
      'label' => t('Node'),
129
130
      'controller class' => 'NodeController',
      'base table' => 'node',
131
      'revision table' => 'node_revision',
132
      'path callback' => 'node_path',
133
      'fieldable' => TRUE,
134
135
136
137
138
139
140
141
      'object keys' => array(
        'id' => 'nid',
        'revision' => 'vid',
        'bundle' => 'type',
      ),
      'bundle keys' => array(
        'bundle' => 'type',
      ),
142
143
      // Node.module handles its own caching.
      // 'cacheable' => FALSE,
144
145
146
147
148
149
150
151
152
153
154
155
      'bundles' => array(),
      'view modes' => array(
        'full' => array(
          'label' => t('Full node'),
        ),
        'teaser' => array(
          'label' => t('Teaser'),
        ),
        'rss' => array(
          'label' => t('RSS'),
        ),
      ),
156
157
    ),
  );
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185

  // Search integration is provided by node.module, so search-related
  // view modes for nodes are defined here and not in search.module.
  if (module_exists('search')) {
    $return['node']['view modes'] += array(
      'search_index' => array(
        'label' => t('Search index'),
      ),
      'search_result' => array(
        'label' => t('Search result'),
      ),
    );
  }

  // Bundles must provide a human readable name so we can create help and error
  // messages, and the path to attach Field admin pages to.
  foreach (node_type_get_names() as $type => $name) {
    $return['node']['bundles'][$type] = array(
      'label' => $name,
      'admin' => array(
        'path' => 'admin/structure/types/manage/%node_type',
        'real path' => 'admin/structure/types/manage/' . str_replace('_', '-', $type),
        'bundle argument' => 4,
        'access arguments' => array('administer content types'),
      ),
    );
  }

186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
  return $return;
}

/**
 * Alter the entity info.
 *
 * Modules may implement this hook to alter the information that defines an
 * entity. All properties that are available in hook_entity_info() can be
 * altered here.
 *
 * @see hook_entity_info()
 *
 * @param $entity_info
 *   The entity info array, keyed by entity name.
 */
function hook_entity_info_alter(&$entity_info) {
  // Set the controller class for nodes to an alternate implementation of the
  // DrupalEntityController interface.
  $entity_info['node']['controller class'] = 'MyCustomNodeController';
}

207
208
209
210
211
212
213
214
215
216
217
218
219
/**
 * Act on entities when loaded.
 *
 * This is a generic load hook called for all entity types loaded via the
 * entity API.
 *
 * @param $entities
 *   The entities keyed by entity ID.
 * @param $type
 *   The type of entities being loaded (i.e. node, user, comment).
 */
function hook_entity_load($entities, $type) {
  foreach ($entities as $entity) {
220
    $entity->foo = mymodule_add_something($entity, $type);
221
222
223
  }
}

224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
/**
 * Act on entities when inserted.
 *
 * Generic insert hook called for all entity types via entity_invoke().
 *
 * @param $entity
 *   The entity object.
 * @param $type
 *   The type of entity being inserted (i.e. node, user, comment).
 */
function hook_entity_insert($entity, $type) {
}

/**
 * Act on entities when updated.
 *
 * Generic update hook called for all entity types via entity_invoke().
 *
 * @param $entity
 *   The entity object.
 * @param $type
 *   The type of entity being updated (i.e. node, user, comment).
 */
function hook_entity_update($entity, $type) {
}

250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
/**
 * Define administrative paths.
 *
 * Modules may specify whether or not the paths they define in hook_menu() are
 * to be considered administrative. Other modules may use this information to
 * display those pages differently (e.g. in a modal overlay, or in a different
 * theme).
 *
 * To change the administrative status of menu items defined in another module's
 * hook_menu(), modules should implement hook_admin_paths_alter().
 *
 * @return
 *   An associative array. For each item, the key is the path in question, in
 *   a format acceptable to drupal_match_path(). The value for each item should
 *   be TRUE (for paths considered administrative) or FALSE (for non-
 *   administrative paths).
 *
 * @see hook_menu()
 * @see drupal_match_path()
 * @see hook_admin_paths_alter()
 */
function hook_admin_paths() {
  $paths = array(
    'mymodule/*/add' => TRUE,
    'mymodule/*/edit' => TRUE,
  );
  return $paths;
}

/**
 * Redefine administrative paths defined by other modules.
 *
 * @param $paths
 *   An associative array of administrative paths, as defined by implementations
 *   of hook_admin_paths().
 *
 * @see hook_admin_paths()
 */
function hook_admin_paths_alter(&$paths) {
  // Treat all user pages as administrative.
  $paths['user'] = TRUE;
  $paths['user/*'] = TRUE;
  // Treat the forum topic node form as a non-administrative page.
  $paths['node/add/forum'] = FALSE;
}

296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
/**
 * Act on entities as they are being prepared for view.
 *
 * Allows you to operate on multiple entities as they are being prepared for
 * view. Only use this if attaching the data during the entity_load() phase
 * is not appropriate, for example when attaching other 'entity' style objects.
 *
 * @param $entities
 *   The entities keyed by entity ID.
 * @param $type
 *   The type of entities being loaded (i.e. node, user, comment).
 */
function hook_entity_prepare_view($entities, $type) {
  // Load a specific node into the user object for later theming.
  if ($type == 'user') {
    $nodes = mymodule_get_user_nodes(array_keys($entities));
    foreach ($entities as $uid => $entity) {
      $entity->user_node = $nodes[$uid];
    }
  }
}

318
319
320
/**
 * Perform periodic actions.
 *
321
322
 * This hook will only be called if cron.php is run (e.g. by crontab).
 *
323
324
325
326
 * Modules that require to schedule some commands to be executed at regular
 * intervals can implement hook_cron(). The engine will then call the hook
 * at the appropriate intervals defined by the administrator. This interface
 * is particularly handy to implement timers or to automate certain tasks.
327
328
 * Database maintenance, recalculation of settings or parameters are good
 * candidates for cron tasks.
329
 *
330
331
332
333
334
335
336
337
338
339
340
341
342
343
 * Short-running or not resource intensive tasks can be executed directly.
 *
 * Long-running tasks should use the queue API. To do this, one or more queues
 * need to be defined via hook_cron_queue_info(). Items that need to be
 * processed are appended to the defined queue, instead of processing them
 * directly in hook_cron().
 * Examples of jobs that are good candidates for
 * hook_cron_queue_info() include automated mailing, retrieving remote data, and
 * intensive file tasks.
 *
 * @return
 *   None.
 *
 * @see hook_cron_queue_info()
344
345
 */
function hook_cron() {
346
347
348
349
350
351
352
  // Short-running operation example, not using a queue:
  // Delete all expired records since the last cron run.
  $expires = variable_get('mymodule_cron_last_run', REQUEST_TIME);
  db_delete('mymodule_table')
    ->condition('expires', $expires, '>=')
    ->execute();
  variable_set('mymodule_cron_last_run', REQUEST_TIME);
353

354
355
356
357
358
359
360
361
362
  // Long-running operation example, leveraging a queue:
  // Fetch feeds from other sites.
  $result = db_query('SELECT * FROM {aggregator_feed} WHERE checked + refresh < :time AND refresh != :never', array(
    ':time' => REQUEST_TIME,
    ':never' => AGGREGATOR_CLEAR_NEVER,
  ));
  $queue = DrupalQueue::get('aggregator_feeds');
  foreach ($result as $feed) {
    $queue->createItem($feed);
363
364
365
  }
}

366
367
368
369
370
371
/**
 * Declare queues holding items that need to be run periodically.
 *
 * While there can be only one hook_cron() process running at the same time,
 * there can be any number of processes defined here running. Because of
 * this, long running tasks are much better suited for this API. Items queued
372
373
374
 * in hook_cron() might be processed in the same cron run if there are not many
 * items in the queue, otherwise it might take several requests, which can be
 * run in parallel.
375
376
377
378
 *
 * @return
 *   An associative array where the key is the queue name and the value is
 *   again an associative array. Possible keys are:
379
380
381
382
383
384
385
 *   - 'worker callback': The name of the function to call. It will be called
 *     with one argument, the item created via DrupalQueue::createItem() in
 *     hook_cron().
 *   - 'time': (optional) How much time Drupal should spend on calling this
 *     worker in seconds. Defaults to 15.
 *
 * @see hook_cron()
386
387
388
389
390
391
392
393
394
 */
function hook_cron_queue_info() {
  $queues['aggregator_feeds'] = array(
    'worker callback' => 'aggregator_refresh',
    'time' => 15,
  );
  return $queues;
}

395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
/**
 * Allows modules to declare their own Forms API element types and specify their
 * default values.
 *
 * This hook allows modules to declare their own form element types and to
 * specify their default values. The values returned by this hook will be
 * merged with the elements returned by hook_form() implementations and so
 * can return defaults for any Form APIs keys in addition to those explicitly
 * mentioned below.
 *
 * Each of the form element types defined by this hook is assumed to have
 * a matching theme function, e.g. theme_elementtype(), which should be
 * registered with hook_theme() as normal.
 *
 * Form more information about custom element types see the explanation at
 * http://drupal.org/node/169815.
 *
 * @return
 *  An associative array describing the element types being defined. The array
 *  contains a sub-array for each element type, with the machine-readable type
 *  name as the key. Each sub-array has a number of possible attributes:
 *  - "#input": boolean indicating whether or not this element carries a value
 *    (even if it's hidden).
418
419
 *  - "#process": array of callback functions taking $element, $form_state,
 *    and $complete_form.
420
421
422
423
424
425
426
 *  - "#after_build": array of callback functions taking $element and $form_state.
 *  - "#validate": array of callback functions taking $form and $form_state.
 *  - "#element_validate": array of callback functions taking $element and
 *    $form_state.
 *  - "#pre_render": array of callback functions taking $element and $form_state.
 *  - "#post_render": array of callback functions taking $element and $form_state.
 *  - "#submit": array of callback functions taking $form and $form_state.
427
428
 *  - "#title_display": optional string indicating if and how #title should be
 *    displayed, see theme_form_element() and theme_form_element_label().
429
430
431
 *
 * @see hook_element_info_alter()
 * @see system_element_info()
432
 */
433
434
435
436
437
function hook_element_info() {
  $types['filter_format'] = array(
    '#input' => TRUE,
  );
  return $types;
438
439
}

440
441
442
443
444
445
446
/**
 * Alter the element type information returned from modules.
 *
 * A module may implement this hook in order to alter the element type defaults
 * defined by a module.
 *
 * @param &$type
447
 *   All element type defaults as collected by hook_element_info().
448
 *
449
 * @see hook_element_info()
450
451
452
453
454
455
456
457
 */
function hook_element_info_alter(&$type) {
  // Decrease the default size of textfields.
  if (isset($type['textfield']['#size'])) {
    $type['textfield']['#size'] = 40;
  }
}

458
459
460
461
/**
 * Perform cleanup tasks.
 *
 * This hook is run at the end of each page request. It is often used for
462
 * page logging and specialized cleanup. This hook MUST NOT print anything.
463
464
465
466
467
468
469
470
471
472
473
474
475
 *
 * Only use this hook if your code must run even for cached page views.
 * If you have code which must run once on all non cached pages, use
 * hook_init instead. Thats the usual case. If you implement this hook
 * and see an error like 'Call to undefined function', it is likely that
 * you are depending on the presence of a module which has not been loaded yet.
 * It is not loaded because Drupal is still in bootstrap mode.
 *
 * @param $destination
 *   If this hook is invoked as part of a drupal_goto() call, then this argument
 *   will be a fully-qualified URL that is the destination of the redirect.
 */
function hook_exit($destination = NULL) {
476
477
478
479
  db_update('counter')
    ->expression('hits', 'hits + 1')
    ->condition('type', 1)
    ->execute();
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
}

/**
 * Perform necessary alterations to the JavaScript before it is presented on
 * the page.
 *
 * @param $javascript
 *   An array of all JavaScript being presented on the page.
 * @see drupal_add_js()
 * @see drupal_get_js()
 * @see drupal_js_defaults()
 */
function hook_js_alter(&$javascript) {
  // Swap out jQuery to use an updated version of the library.
  $javascript['misc/jquery.js']['data'] = drupal_get_path('module', 'jquery_update') . '/jquery.js';
}

497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
/**
 * Registers JavaScript/CSS libraries associated with a module.
 *
 * Modules implementing this return an array of arrays. The key to each
 * sub-array is the machine readable name of the library. Each library may
 * contain the following items:
 *
 * - 'title': The human readable name of the library.
 * - 'website': The URL of the library's web site.
 * - 'version': A string specifying the version of the library; intentionally
 *   not a float because a version like "1.2.3" is not a valid float. Use PHP's
 *   version_compare() to compare different versions.
 * - 'js': An array of JavaScript elements; each element's key is used as $data
 *   argument, each element's value is used as $options array for
 *   drupal_add_js(). To add library-specific (not module-specific) JavaScript
 *   settings, the key may be skipped, the value must specify
 *   'type' => 'setting', and the actual settings must be contained in a 'data'
 *   element of the value.
 * - 'css': Like 'js', an array of CSS elements passed to drupal_add_css().
 * - 'dependencies': An array of libraries that are required for a library. Each
 *   element is an array containing the module and name of the registered
 *   library. Note that all dependencies for each dependent library will be
 *   added when this library is added.
 *
 * Registered information for a library should contain re-usable data only.
 * Module- or implementation-specific data and integration logic should be added
 * separately.
 *
 * @return
 *   An array defining libraries associated with a module.
 *
 * @see system_library()
 * @see drupal_add_library()
 * @see drupal_get_library()
 */
function hook_library() {
  // Library One.
  $libraries['library-1'] = array(
    'title' => 'Library One',
    'website' => 'http://example.com/library-1',
    'version' => '1.2',
    'js' => array(
      drupal_get_path('module', 'my_module') . '/library-1.js' => array(),
    ),
    'css' => array(
      drupal_get_path('module', 'my_module') . '/library-2.css' => array(
        'type' => 'file',
        'media' => 'screen',
      ),
    ),
  );
  // Library Two.
  $libraries['library-2'] = array(
    'title' => 'Library Two',
    'website' => 'http://example.com/library-2',
    'version' => '3.1-beta1',
    'js' => array(
      // JavaScript settings may use the 'data' key.
      array(
        'type' => 'setting',
        'data' => array('library2' => TRUE),
      ),
    ),
    'dependencies' => array(
      // Require jQuery UI core by System module.
      array('system' => 'ui'),
      // Require our other library.
      array('my_module', 'library-1'),
      // Require another library.
      array('other_module', 'library-3'),
    ),
  );
  return $libraries;
}

/**
 * Alters the JavaScript/CSS library registry.
 *
 * Allows certain, contributed modules to update libraries to newer versions
 * while ensuring backwards compatibility. In general, such manipulations should
 * only be done by designated modules, since most modules that integrate with a
 * certain library also depend on the API of a certain library version.
 *
 * @param $libraries
 *   The JavaScript/CSS libraries provided by $module. Keyed by internal library
 *   name and passed by reference.
 * @param $module
 *   The name of the module that registered the libraries.
 *
 * @see hook_library()
 */
function hook_library_alter(&$libraries, $module) {
  // Update Farbtastic to version 2.0.
  if ($module == 'system' && isset($libraries['farbtastic'])) {
    // Verify existing version is older than the one we are updating to.
    if (version_compare($libraries['farbtastic']['version'], '2.0', '<')) {
      // Update the existing Farbtastic to version 2.0.
      $libraries['farbtastic']['version'] = '2.0';
      $libraries['farbtastic']['js'] = array(
        drupal_get_path('module', 'farbtastic_update') . '/farbtastic-2.0.js' => array(),
      );
    }
  }
}

602
603
604
605
606
607
608
609
610
611
612
613
614
/**
 * Alter CSS files before they are output on the page.
 *
 * @param $css
 *   An array of all CSS items (files and inline CSS) being requested on the page.
 * @see drupal_add_css()
 * @see drupal_get_css()
 */
function hook_css_alter(&$css) {
  // Remove defaults.css file.
  unset($css[drupal_get_path('module', 'system') . '/defaults.css']);
}

615
616
617
618
619
620
621
622
623
624
625
626
/**
 * Alter the commands that are sent to the user through the AJAX framework.
 *
 * @param $commands
 *   An array of all commands that will be sent to the user.
 * @see ajax_render()
 */
function hook_ajax_render_alter($commands) {
  // Inject any new status messages into the content area.
  $commands[] = ajax_command_prepend('#block-system-main .content', theme('status_messages'));
}

627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
/**
 * Add elements to a page before it is rendered.
 *
 * Use this hook when you want to add elements at the page level. For your
 * additions to be printed, they have to be placed below a top level array key
 * of the $page array that has the name of a region of the active theme.
 *
 * By default, valid region keys are 'page_top', 'header', 'sidebar_first',
 * 'content', 'sidebar_second' and 'page_bottom'. To get a list of all regions
 * of the active theme, use system_region_list($theme). Note that $theme is a
 * global variable.
 *
 * If you want to alter the elements added by other modules or if your module
 * depends on the elements of other modules, use hook_page_alter() instead which
 * runs after this hook.
 *
 * @param $page
 *   Nested array of renderable elements that make up the page.
 *
 * @see hook_page_alter()
 * @see drupal_render_page()
 */
function hook_page_build(&$page) {
  if (menu_get_object('node', 1)) {
    // We are on a node detail page. Append a standard disclaimer to the
    // content region.
    $page['content']['disclaimer'] = array(
      '#markup' => t('Acme, Inc. is not responsible for the contents of this sample code.'),
      '#weight' => 25,
    );
  }
}

660
661
662
/**
 * Perform alterations before a page is rendered.
 *
663
664
665
666
667
 * Use this hook when you want to remove or alter elements at the page
 * level, or add elements at the page level that depend on an other module's
 * elements (this hook runs after hook_page_build().
 *
 * If you are making changes to entities such as forms, menus, or user
668
669
670
671
672
 * profiles, use those objects' native alter hooks instead (hook_form_alter(),
 * for example).
 *
 * The $page array contains top level elements for each block region:
 * @code
673
 *   $page['page_top']
674
 *   $page['header']
675
 *   $page['sidebar_first']
676
 *   $page['content']
677
 *   $page['sidebar_second']
678
 *   $page['page_bottom']
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
 * @endcode
 *
 * The 'content' element contains the main content of the current page, and its
 * structure will vary depending on what module is responsible for building the
 * page. Some legacy modules may not return structured content at all: their
 * pre-rendered markup will be located in $page['content']['main']['#markup'].
 *
 * Pages built by Drupal's core Node and Blog modules use a standard structure:
 *
 * @code
 *   // Node body.
 *   $page['content']['nodes'][$nid]['body']
 *   // Array of links attached to the node (add comments, read more).
 *   $page['content']['nodes'][$nid]['links']
 *   // The node object itself.
 *   $page['content']['nodes'][$nid]['#node']
 *   // The results pager.
 *   $page['content']['pager']
697
 * @endcode
698
699
700
 *
 * Blocks may be referenced by their module/delta pair within a region:
 * @code
701
 *   // The login block in the first sidebar region.
702
 *   $page['sidebar_first']['user_login']['#block'];
703
704
705
706
707
 * @endcode
 *
 * @param $page
 *   Nested array of renderable elements that make up the page.
 *
708
 * @see hook_page_build()
709
710
 * @see drupal_render_page()
 */
711
712
713
714
715
716
function hook_page_alter(&$page) {
  // Add help text to the user login block.
  $page['sidebar_first']['user_login']['help'] = array(
    '#weight' => -10,
    '#markup' => t('To post comments or add new content, you first have to log in.'),
  );
717
718
}

719
720
721
722
723
724
/**
 * Perform alterations before a form is rendered.
 *
 * One popular use of this hook is to add form elements to the node form. When
 * altering a node form, the node object retrieved at from $form['#node'].
 *
725
726
 * Note that instead of hook_form_alter(), which is called for all forms, you
 * can also use hook_form_FORM_ID_alter() to alter a specific form.
727
 *
728
729
730
731
732
733
734
735
 * @param $form
 *   Nested array of form elements that comprise the form.
 * @param $form_state
 *   A keyed array containing the current state of the form.
 * @param $form_id
 *   String representing the name of the form itself. Typically this is the
 *   name of the function that generated the form.
 */
736
function hook_form_alter(&$form, &$form_state, $form_id) {
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
  if (isset($form['type']) && $form['type']['#value'] . '_node_settings' == $form_id) {
    $form['workflow']['upload_' . $form['type']['#value']] = array(
      '#type' => 'radios',
      '#title' => t('Attachments'),
      '#default_value' => variable_get('upload_' . $form['type']['#value'], 1),
      '#options' => array(t('Disabled'), t('Enabled')),
    );
  }
}

/**
 * Provide a form-specific alteration instead of the global hook_form_alter().
 *
 * Modules can implement hook_form_FORM_ID_alter() to modify a specific form,
 * rather than implementing hook_form_alter() and checking the form ID, or
 * using long switch statements to alter multiple forms.
 *
 * Note that this hook fires before hook_form_alter(). Therefore all
 * implementations of hook_form_FORM_ID_alter() will run before all implementations
 * of hook_form_alter(), regardless of the module order.
 *
 * @param $form
 *   Nested array of form elements that comprise the form.
 * @param $form_state
 *   A keyed array containing the current state of the form.
 *
 * @see drupal_prepare_form().
 */
function hook_form_FORM_ID_alter(&$form, &$form_state) {
  // Modification for the form with the given form ID goes here. For example, if
767
  // FORM_ID is "user_register_form" this code would run only on the user
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
  // registration form.

  // Add a checkbox to registration form about agreeing to terms of use.
  $form['terms_of_use'] = array(
    '#type' => 'checkbox',
    '#title' => t("I agree with the website's terms and conditions."),
    '#required' => TRUE,
  );
}

/**
 * Map form_ids to builder functions.
 *
 * This hook allows modules to build multiple forms from a single form "factory"
 * function but each form will have a different form id for submission,
 * validation, theming or alteration by other modules.
 *
785
786
787
788
789
 * The 'callback arguments' will be passed as parameters to the function defined
 * in 'callback'. In case the code that calls drupal_get_form() also passes
 * parameters, then the 'callback' function will receive the
 * 'callback arguments' specified in hook_forms() before those that have been
 * passed to drupal_get_form().
790
791
792
793
 *
 * See node_forms() for an actual example of how multiple forms share a common
 * building function.
 *
794
795
796
797
 * @param $form_id
 *   The unique string identifying the desired form.
 * @param $args
 *   An array containing the original arguments provided to drupal_get_form().
798
799
800
 *   These are always passed to the form builder and do not have to be specified
 *   manually in 'callback arguments'.
 *
801
 * @return
802
803
804
805
806
807
808
809
810
811
812
813
814
 *   An associative array whose keys define form_ids and whose values are an
 *   associative array defining the following keys:
 *   - callback: The name of the form builder function to invoke.
 *   - callback arguments: (optional) Additional arguments to pass to the
 *     function defined in 'callback', which are prepended to $args.
 *   - wrapper_callback: (optional) The name of a form builder function to
 *     invoke before the form builder defined in 'callback' is invoked. This
 *     wrapper callback may prepopulate the $form array with form elements,
 *     which will then be already contained in the $form that is passed on to
 *     the form builder defined in 'callback'. For example, a wrapper callback
 *     could setup wizard-alike form buttons that are the same for a variety of
 *     forms that belong to the wizard, which all share the same wrapper
 *     callback.
815
 */
816
function hook_forms($form_id, $args) {
817
818
  // Simply reroute the (non-existing) $form_id 'mymodule_first_form' to
  // 'mymodule_main_form'.
819
  $forms['mymodule_first_form'] = array(
820
    'callback' => 'mymodule_main_form',
821
  );
822
823
824

  // Reroute the $form_id and prepend an additional argument that gets passed to
  // the 'mymodule_main_form' form builder function.
825
  $forms['mymodule_second_form'] = array(
826
827
828
829
830
831
832
833
834
835
    'callback' => 'mymodule_main_form',
    'callback arguments' => array('some parameter'),
  );

  // Reroute the $form_id, but invoke the form builder function
  // 'mymodule_main_form_wrapper' first, so we can prepopulate the $form array
  // that is passed to the actual form builder 'mymodule_main_form'.
  $forms['mymodule_wrapped_form'] = array(
    'callback' => 'mymodule_main_form',
    'wrapper_callback' => 'mymodule_main_form_wrapper',
836
  );
837

838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
  return $forms;
}

/**
 * Perform setup tasks. See also, hook_init.
 *
 * This hook is run at the beginning of the page request. It is typically
 * used to set up global parameters which are needed later in the request.
 *
 * Only use this hook if your code must run even for cached page views.This hook
 * is called before modules or most include files are loaded into memory.
 * It happens while Drupal is still in bootstrap mode.
 */
function hook_boot() {
  // we need user_access() in the shutdown function. make sure it gets loaded
  drupal_load('module', 'user');
854
  drupal_register_shutdown_function('devel_shutdown');
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
}

/**
 * Perform setup tasks. See also, hook_boot.
 *
 * This hook is run at the beginning of the page request. It is typically
 * used to set up global parameters which are needed later in the request.
 * when this hook is called, all modules are already loaded in memory.
 *
 * For example, this hook is a typical place for modules to add CSS or JS
 * that should be present on every page. This hook is not run on cached
 * pages - though CSS or JS added this way will be present on a cached page.
 */
function hook_init() {
  drupal_add_css(drupal_get_path('module', 'book') . '/book.css');
}

/**
873
874
875
876
877
878
879
880
881
882
883
884
 * Define image toolkits provided by this module.
 *
 * The file which includes each toolkit's functions must be declared as part of
 * the files array in the module .info file so that the registry will find and
 * parse it.
 *
 * The toolkit's functions must be named image_toolkitname_operation().
 * where the operation may be:
 *   - 'load': Required. See image_gd_load() for usage.
 *   - 'save': Required. See image_gd_save() for usage.
 *   - 'settings': Optional. See image_gd_settings() for usage.
 *   - 'resize': Optional. See image_gd_resize() for usage.
885
 *   - 'rotate': Optional. See image_gd_rotate() for usage.
886
887
888
889
890
891
892
893
894
895
896
 *   - 'crop': Optional. See image_gd_crop() for usage.
 *   - 'desaturate': Optional. See image_gd_desaturate() for usage.
 *
 * @return
 *   An array with the toolkit name as keys and sub-arrays with these keys:
 *     - 'title': A string with the toolkit's title.
 *     - 'available': A Boolean value to indicate that the toolkit is operating
 *       properly, e.g. all required libraries exist.
 *
 * @see system_image_toolkits()
 */
897
function hook_image_toolkits() {
898
899
900
901
902
903
904
905
906
907
  return array(
    'working' => array(
      'title' => t('A toolkit that works.'),
      'available' => TRUE,
    ),
    'broken' => array(
      'title' => t('A toolkit that is "broken" and will not be listed.'),
      'available' => FALSE,
    ),
  );
908
909
910
}

/**
911
912
913
914
915
916
917
918
 * Alter an email message created with the drupal_mail() function.
 *
 * hook_mail_alter() allows modification of email messages created and sent
 * with drupal_mail(). Usage examples include adding and/or changing message
 * text, message fields, and message headers.
 *
 * Email messages sent using functions other than drupal_mail() will not
 * invoke hook_mail_alter(). For example, a contributed module directly
919
 * calling the drupal_mail_system()->mail() or PHP mail() function
920
 * will not invoke this hook. All core modules use drupal_mail() for
921
 * messaging, it is best practice but not mandatory in contributed modules.
922
923
 *
 * @param $message
924
 *   An array containing the message data. Keys in this array include:
925
 *  - 'id':
926
 *     The drupal_mail() id of the message. Look at module source code or
927
 *     drupal_mail() for possible id values.
928
 *  - 'to':
929
 *     The address or addresses the message will be sent to. The
930
 *     formatting of this string must comply with RFC 2822.
931
 *  - 'from':
932
933
 *     The address the message will be marked as being from, which is
 *     either a custom address or the site-wide default email address.
934
935
936
937
938
 *  - 'subject':
 *     Subject of the email to be sent. This must not contain any newline
 *     characters, or the email may not be sent properly.
 *  - 'body':
 *     An array of strings containing the message text. The message body is
939
 *     created by concatenating the individual array strings into a single text
940
941
 *     string using "\n\n" as a separator.
 *  - 'headers':
942
 *     Associative array containing mail headers, such as From, Sender,
943
 *     MIME-Version, Content-Type, etc.
944
945
946
947
948
949
950
951
 *  - 'params':
 *     An array of optional parameters supplied by the caller of drupal_mail()
 *     that is used to build the message before hook_mail_alter() is invoked.
 *  - 'language':
 *     The language object used to build the message before hook_mail_alter()
 *     is invoked.
 *
 * @see drupal_mail()
952
953
 */
function hook_mail_alter(&$message) {
954
955
  if ($message['id'] == 'modulename_messagekey') {
    $message['body'][] = "--\nMail sent out from " . variable_get('sitename', t('Drupal'));
956
957
958
959
960
961
  }
}

/**
 * Alter the information parsed from module and theme .info files
 *
962
963
964
965
 * This hook is invoked in _system_rebuild_module_data() and in
 * _system_rebuild_theme_data(). A module may implement this hook in order to
 * add to or alter the data generated by reading the .info file with
 * drupal_parse_info_file().
966
967
968
969
970
971
 *
 * @param &$info
 *   The .info file contents, passed by reference so that it can be altered.
 * @param $file
 *   Full information about the module or theme, including $file->name, and
 *   $file->filename
972
973
974
 * @param $type
 *   Either 'module' or 'theme', depending on the type of .info file that was
 *   passed.
975
 */
976
function hook_system_info_alter(&$info, $file, $type) {
977
978
979
980
981
982
983
984
985
986
  // Only fill this in if the .info file does not define a 'datestamp'.
  if (empty($info['datestamp'])) {
    $info['datestamp'] = filemtime($file->filename);
  }
}

/**
 * Define user permissions.
 *
 * This hook can supply permissions that the module defines, so that they
987
 * can be selected on the user permissions page and used to grant or restrict
988
989
990
991
992
 * access to actions the module performs.
 *
 * Permissions are checked using user_access().
 *
 * For a detailed usage example, see page_example.module.
993
 *
994
995
996
997
998
999
1000
1001
 * @return
 *   An array of which permission names are the keys and their corresponding
 *   values are descriptions of each permission.
 *   The permission names (keys of the array) must not be wrapped with
 *   the t() function, since the string extractor takes care of
 *   extracting permission names defined in the perm hook for
 *   translation. The permission descriptions (values of the array)
 *   should be wrapped in the t() function so they can be translated.
1002
 */
1003
function hook_permission() {
1004
  return array(
1005
1006
1007
1008
    'administer my module' =>  array(
      'title' => t('Administer my module'),
      'description' => t('Perform administration tasks for my module.'),
    ),
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
  );
}

/**
 * Register a module (or theme's) theme implementations.
 *
 * Modules and themes implementing this return an array of arrays. The key
 * to each sub-array is the internal name of the hook, and the array contains
 * info about the hook. Each array may contain the following items:
 *
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
 * - variables: (required if "render element" not present) An array of
 *   variables that this theme hook uses. This value allows the theme layer to
 *   properly utilize templates. Each array key represents the name of the
 *   variable and the value will be used as the default value if it is not given
 *   when theme() is called. Template implementations receive these arguments as
 *   variables in the template file. Function implementations are passed this
 *   array data in the $variables parameter.
 * - render element: (required if "variables" not present) A string that is the
 *   name of the sole renderable element to pass to the theme function. The
 *   string represents the name of the "variable" that will hold the renderable
 *   array inside any optional preprocess or process functions. Cannot be used
 *   with the "variables" item; only one or the other, not both, can be present
 *   in a hook's info array.
1032
1033
1034
1035
 * - file: The file the implementation resides in. This file will be included
 *   prior to the theme being rendered, to make sure that the function or
 *   preprocess function (as needed) is actually loaded; this makes it possible
 *   to split theme functions out into separate files quite easily.
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
 * - path: Override the path of the file to be used. Ordinarily the module or
 *   theme path will be used, but if the file will not be in the default path,
 *   include it here. This path should be relative to the Drupal root
 *   directory.
 * - template: If specified, this theme implementation is a template, and this
 *   is the template file <b>without an extension</b>. Do not put .tpl.php
 *   on this file; that extension will be added automatically by the default
 *   rendering engine (which is PHPTemplate). If 'path', above, is specified,
 *   the template should also be in this path.
 * - function: If specified, this will be the function name to invoke for this
 *   implementation. If neither file nor function is specified, a default
 *   function name will be assumed. For example, if a module registers
 *   the 'node' theme hook, 'theme_node' will be assigned to its function.
 *   If the chameleon theme registers the node hook, it will be assigned
 *   'chameleon_node' as its function.
 * - pattern: A regular expression pattern to be used to allow this theme
 *   implementation to have a dynamic name. The convention is to use __ to
 *   differentiate the dynamic portion of the theme. For example, to allow
 *   forums to be themed individually, the pattern might be: 'forum__'. Then,
 *   when the forum is themed, call: <code>theme(array('forum__' . $tid, 'forum'),
 *   $forum)</code>.
 * - preprocess functions: A list of functions used to preprocess this data.
 *   Ordinarily this won't be used; it's automatically filled in. By default,
 *   for a module this will be filled in as template_preprocess_HOOK. For
 *   a theme this will be filled in as phptemplate_preprocess and
 *   phptemplate_preprocess_HOOK as well as themename_preprocess and
 *   themename_preprocess_HOOK.
 * - override preprocess functions: Set to TRUE when a theme does NOT want the
 *   standard preprocess functions to run. This can be used to give a theme
 *   FULL control over how variables are set. For example, if a theme wants
 *   total control over how certain variables in the page.tpl.php are set,
 *   this can be set to true. Please keep in mind that when this is used
 *   by a theme, that theme becomes responsible for making sure necessary
 *   variables are set.
 * - type: (automatically derived) Where the theme hook is defined:
 *   'module', 'theme_engine', or 'theme'.
 * - theme path: (automatically derived) The directory path of the theme or
 *   module, so that it doesn't need to be looked up.
 *
 * The following parameters are all optional.
 *
 * @param $existing
 *   An array of existing implementations that may be used for override
 *   purposes. This is primarily useful for themes that may wish to examine
 *   existing implementations to extract data (such as arguments) so that
 *   it may properly register its own, higher priority implementations.
 * @param $type
 *   What 'type' is being processed. This is primarily useful so that themes
 *   tell if they are the actual theme being called or a parent theme.
 *   May be one of:
 *     - module: A module is being checked for theme implementations.
 *     - base_theme_engine: A theme engine is being checked for a theme which is a parent of the actual theme being used.
 *     - theme_engine: A theme engine is being checked for the actual theme being used.
 *     - base_theme: A base theme is being checked for theme implementations.
 *     - theme: The actual theme in use is being checked.
 * @param $theme
 *   The actual name of theme that is being being checked (mostly only useful for
 *   theme engine).
 * @param $path
 *   The directory path of the theme or module, so that it doesn't need to be
 *   looked up.
 *
 * @return
 *   A keyed array of theme hooks.
 */
function hook_theme($existing, $type, $theme, $path) {
  return array(
    'forum_display' => array(
1104
      'variables' => array('forums' => NULL, 'topics' => NULL, 'parents' => NULL, 'tid' => NULL, 'sortby' => NULL, 'forum_per_page' => NULL),
1105
1106
    ),
    'forum_list' => array(
1107
      'variables' => array('forums' => NULL, 'parents' => NULL, 'tid' => NULL),
1108
1109
    ),
    'forum_topic_list' => array(
1110
      'variables' => array('tid' => NULL, 'topics' => NULL, 'sortby' => NULL, 'forum_per_page' => NULL),
1111
1112
    ),
    'forum_icon' => array(
1113
1114
1115
1116
1117
1118
1119
1120
1121
      'variables' => array('new_posts' => NULL, 'num_posts' => 0, 'comment_mode' => 0, 'sticky' => 0),
    ),
    'status_report' => array(
      'render element' => 'requirements',
      'file' => 'system.admin.inc',
    ),
    'system_date_time_settings' => array(
      'render element' => 'form',
      'file' => 'system.admin.inc',
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
    ),
  );
}

/**
 * Alter the theme registry information returned from hook_theme().
 *
 * The theme registry stores information about all available theme hooks,
 * including which callback functions those hooks will call when triggered,
 * what template files are exposed by these hooks, and so on.
 *
 * Note that this hook is only executed as the theme cache is re-built.
 * Changes here will not be visible until the next cache clear.
 *
 * The $theme_registry array is keyed by theme hook name, and contains the
 * information returned from hook_theme(), as well as additional properties
 * added by _theme_process_registry().
 *
 * For example:
 * @code
 *  $theme_registry['user_profile'] = array(
1143
 *    'variables' => array(
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
 *      'account' => NULL,
 *    ),
 *    'template' => 'modules/user/user-profile',
 *    'file' => 'modules/user/user.pages.inc',
 *    'type' => 'module',
 *    'theme path' => 'modules/user',
 *    'preprocess functions' => array(
 *      0 => 'template_preprocess',
 *      1 => 'template_preprocess_user_profile',
 *     ),
 *   )
 * );
 * @endcode
 *
 * @param $theme_registry
 *   The entire cache of theme registry information, post-processing.
 * @see hook_theme()
 * @see _theme_process_registry()
 */
function hook_theme_registry_alter(&$theme_registry) {
  // Kill the next/previous forum topic navigation links.
  foreach ($theme_registry['forum_topic_navigation']['preprocess functions'] as $key => $value) {
    if ($value = 'template_preprocess_forum_topic_navigation') {
      unset($theme_registry['forum_topic_navigation']['preprocess functions'][$key]);
    }
  }
}

1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
/**
 * Return the machine-readable name of the theme to use for the current page.
 *
 * This hook can be used to dynamically set the theme for the current page
 * request. It overrides the default theme as well as any per-page or
 * per-section theme set by the theme callback function in hook_menu(). This
 * should be used by modules which need to override the theme based on dynamic
 * conditions.
 *
 * Since only one theme can be used at a time, the last (i.e., highest
 * weighted) module which returns a valid theme name from this hook will
 * prevail.
 *
 * @return
 *   The machine-readable name of the theme that should be used for the current
 *   page request. The value returned from this function will only have an
 *   effect if it corresponds to a currently-active theme on the site.
 */
function hook_custom_theme() {
  // Allow the user to request a particular theme via a query parameter.
  if (isset($_GET['theme'])) {
    return $_GET['theme'];
  }
}

1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
/**
 * Register XML-RPC callbacks.
 *
 * This hook lets a module register callback functions to be called when
 * particular XML-RPC methods are invoked by a client.
 *
 * @return
 *   An array which maps XML-RPC methods to Drupal functions. Each array
 *   element is either a pair of method => function or an array with four
 *   entries:
 *   - The XML-RPC method name (for example, module.function).
 *   - The Drupal callback function (for example, module_function).
 *   - The method signature is an array of XML-RPC types. The first element
 *     of this array is the type of return value and then you should write a
 *     list of the types of the parameters. XML-RPC types are the following
 *     (See the types at http://www.xmlrpc.com/spec):
 *       - "boolean": 0 (false) or 1 (true).
 *       - "double": a floating point number (for example, -12.214).
 *       - "int": a integer number (for example,  -12).
 *       - "array": an array without keys (for example, array(1, 2, 3)).
 *       - "struct": an associative array or an object (for example,
 *          array('one' => 1, 'two' => 2)).
 *       - "date": when you return a date, then you may either return a
 *          timestamp (time(), mktime() etc.) or an ISO8601 timestamp. When
 *          date is specified as an input parameter, then you get an object,
 *          which is described in the function xmlrpc_date
 *       - "base64": a string containing binary data, automatically
 *          encoded/decoded automatically.
 *       - "string": anything else, typically a string.
 *   - A descriptive help string, enclosed in a t() function for translation
 *     purposes.
 *   Both forms are shown in the example.
 */
function hook_xmlrpc() {
  return array(
    'drupal.login' => 'drupal_login',
    array(
      'drupal.site.ping',
      'drupal_directory_ping',
      array('boolean', 'string', 'string', 'string', 'string', 'string'),
      t('Handling ping request'))
  );
}

1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
/**
 * Alter the definition of XML-RPC methods before they are called.
 *
 * This hook lets at module modify the callback definition for already
 * declared XML-RPC methods, when they are being invoked by a client.
 *
 * This hook is invoked by xmlrpc.php. The method definitions are
 * passed in by reference. Each element of the $methods array is one
 * callback definition returned by a module from hook_xmlrpc. Additional
 * methods may be added, or existing items altered.
 *
 * Modules implementing this hook must take care of the fact that
 * hook_xmlrpc allows two distinct and incompatible formats for callback
 * definition, so module must be prepared to handle either format for
 * each callback being altered.
 *
 * @see hook_xmlrpc()
 *
 * @param $methods
 *   Associative array of method callback definitions returned from
 *   hook_xmlrpc.
 */
function hook_xmlrpc_alter(&$methods) {

  // Direct update for methods defined the simple way
  $methods['drupal.login'] = 'mymodule_login';

  // Lookup update for methods defined the complex way
  foreach ($methods as $key => &$method) {
    if (!is_int($key)) {
      continue;
    }
    if ($method[0] == 'drupal.site.ping') {
      $method[1] = 'mymodule_directory_ping';
    }
  }
}

1279
1280
1281
1282
1283
1284
1285
/**
 * Log an event message
 *
 * This hook allows modules to route log events to custom destinations, such as
 * SMS, Email, pager, syslog, ...etc.
 *
 * @param $log_entry
1286
 *   An associative array containing the following keys:
1287
1288
1289
1290
1291
1292
 *   - type: The type of message for this entry. For contributed modules, this is
 *     normally the module name. Do not use 'debug', use severity WATCHDOG_DEBUG instead.
 *   - user: The user object for the user who was logged in when the event happened.
 *   - request_uri: The Request URI for the page the event happened in.
 *   - referer: The page that referred the use to the page where the event occurred.
 *   - ip: The IP address where the request for the page came from.
1293
 *   - timestamp: The UNIX timestamp of the date/time the event occurred
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
 *   - severity: One of the following values as defined in RFC 3164 http://www.faqs.org/rfcs/rfc3164.html
 *     WATCHDOG_EMERG     Emergency: system is unusable
 *     WATCHDOG_ALERT     Alert: action must be taken immediately
 *     WATCHDOG_CRITICAL  Critical: critical conditions
 *     WATCHDOG_ERROR     Error: error conditions
 *     WATCHDOG_WARNING   Warning: warning conditions
 *     WATCHDOG_NOTICE    Notice: normal but significant condition
 *     WATCHDOG_INFO      Informational: informational messages
 *     WATCHDOG_DEBUG     Debug: debug-level messages
 *   - link: an optional link provided by the module that called the watchdog() function.
 *   - message: The text of the message to be logged.
 */
1306
1307
function hook_watchdog(array $log_entry) {
  global $base_url, $language;
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319

  $severity_list = array(
    WATCHDOG_EMERG    => t('Emergency'),
    WATCHDOG_ALERT    => t('Alert'),
    WATCHDOG_CRITICAL => t('Critical'),
    WATCHDOG_ERROR    => t('Error'),
    WATCHDOG_WARNING  => t('Warning'),
    WATCHDOG_NOTICE   => t('Notice'),
    WATCHDOG_INFO     => t('Info'),
    WATCHDOG_DEBUG    => t('Debug'),
  );

1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
  $to = 'someone@example.com';
  $params = array();
  $params['subject'] = t('[@site_name] @severity_desc: Alert from your web site', array(
    '@site_name' => variable_get('site_name', 'Drupal'),
    '@severity_desc' => $severity_list[$log_entry['severity']],
  ));

  $params['message']  = "\nSite:         @base_url";
  $params['message'] .= "\nSeverity:     (@severity) @severity_desc";
  $params['message'] .= "\nTimestamp:    @timestamp";
  $params['message'] .= "\nType:         @type";
  $params['message'] .= "\nIP Address:   @ip";
  $params['message'] .= "\nRequest URI:  @request_uri";
  $params['message'] .= "\nReferrer URI: @referer_uri";
  $params['message'] .= "\nUser:         (@uid) @name";
  $params['message'] .= "\nLink:         @link";
  $params['message'] .= "\nMessage:      \n\n@message";

  $params['message'] = t($params['message'], array(
1339
    '@base_url'      => $base_url,
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
    '@severity'      => $log_entry['severity'],
    '@severity_desc' => $severity_list[$log_entry['severity']],
    '@timestamp'     => format_date($log_entry['timestamp']),
    '@type'          => $log_entry['type'],
    '@ip'            => $log_entry['ip'],
    '@request_uri'   => $log_entry['request_uri'],
    '@referer_uri'   => $log_entry['referer'],
    '@uid'           => $log_entry['user']->uid,
    '@name'          => $log_entry['user']->name,
    '@link'          => strip_tags($log_entry['link']),
    '@message'       => strip_tags($log_entry['message']),
1351
1352
  ));

1353
  drupal_mail('emaillog', 'entry', $to, $language, $params);
1354
1355
1356
}

/**
1357
 * Prepare a message based on parameters; called from drupal_mail().
1358
1359
1360
1361
1362
 *
 * @param $key
 *   An identifier of the mail.
 * @param $message
 *  An array to be filled in. Keys in this array include:
1363
1364
1365
 *  - 'id':
 *     An id to identify the mail sent. Look at module source code
 *     or drupal_mail() for possible id values.
1366
 *  - 'to':
1367
 *     The address or addresses the message will be sent to. The
1368
1369
1370
 *     formatting of this string must comply with RFC 2822.
 *  - 'subject':
 *     Subject of the e-mail to be sent. This must not contain any newline
1371
1372
 *     characters, or the mail may not be sent properly. drupal_mail() sets
 *     this to an empty string when the hook is invoked.
1373
1374
 *  - 'body':
 *     An array of lines containing the message to be sent. Drupal will format
1375
1376
 *     the correct line endings for you. drupal_mail() sets this to an empty
 *     array when the hook is invoked.
1377
 *  - 'from':
1378
 *     The address the message will be marked as being from, which is
1379
 *     set by drupal_mail() to either a custom address or the site-wide
1380
 *     default email address when the hook is invoked.
1381
 *  - 'headers':
1382
1383
1384
 *     Associative array containing mail headers, such as From, Sender,
 *     MIME-Version, Content-Type, etc. drupal_mail() pre-fills
 *     several headers in this array.
1385
 * @param $params
1386
 *   An array of parameters supplied by the caller of drupal_mail().
1387
1388
1389
1390
1391
1392
 */
function hook_mail($key, &$message, $params) {
  $account = $params['account'];
  $context = $params['context'];
  $variables = array(
    '%site_name' => variable_get('site_name', 'Drupal'),
1393
    '%username' => format_username($account),
1394
1395
  );
  if ($context['hook'] == 'taxonomy') {
1396
1397
    $entity = $params['object'];
    $vocabulary = taxonomy_vocabulary_load($entity->vid);
1398
    $variables += array(
1399
1400
1401
      '%term_name' => $entity->name,
      '%term_description' => $entity->description,
      '%term_id' => $entity->tid,
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
      '%vocabulary_name' => $vocabulary->name,
      '%vocabulary_description' => $vocabulary->description,
      '%vocabulary_id' => $vocabulary->vid,
    );
  }

  // Node-based variable translation is only available if we have a node.
  if (isset($params['node'])) {
    $node = $params['node'];
    $variables += array(
      '%uid' => $node->uid,
      '%node_url' => url('node/' . $node->nid, array('absolute' => TRUE)),
1414
      '%node_type' => node_type_get_name($node),
1415
      '%title' => $node->title,
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
      '%teaser' => $node->teaser,
      '%body' => $node->body,
    );
  }
  $subject = strtr($context['subject'], $variables);
  $body = strtr($context['message'], $variables);
  $message['subject'] .= str_replace(array("\r", "\n"), '', $subject);
  $message['body'][] = drupal_html_to_text($body);
}

/**
 * Add a list of cache tables to be cleared.
 *
 * This hook allows your module to add cache table names to the list of cache
 * tables that will be cleared by the Clear button on the Performance page or
 * whenever drupal_flush_all_caches is invoked.
 *
 * @see drupal_flush_all_caches()
 *
 * @return
 *   An array of cache table names.
 */
function hook_flush_caches() {
  return array('cache_example');
}

/**
 * Perform necessary actions after modules are installed.
 *
 * This function differs from hook_install() as it gives all other
 * modules a chance to perform actions when a module is installed,
 * whereas hook_install() will only be called on the module actually
 * being installed.
 *
 * @see hook_install()
 *
 * @param $modules
 *   An array of the installed modules.
 */
function hook_modules_installed($modules) {
  if (in_array('lousy_module', $modules)) {
    variable_set('lousy_module_conflicting_variable', FALSE);
  }
}

/**
 * Perform necessary actions after modules are enabled.
 *
 * This function differs from hook_enable() as it gives all other
 * modules a chance to perform actions when modules are enabled,
 * whereas hook_enable() will only be called on the module actually
 * being enabled.
 *
 * @see hook_enable()
 *
 * @param $modules
 *   An array of the enabled modules.
 */
function hook_modules_enabled($modules) {
  if (in_array('lousy_module', $modules)) {
    drupal_set_message(t('mymodule is not compatible with lousy_module'), 'error');
    mymodule_disable_functionality();
  }
}

/**
 * Perform necessary actions after modules are disabled.
 *
 * This function differs from hook_disable() as it gives all other
 * modules a chance to perform actions when modules are disabled,
 * whereas hook_disable() will only be called on the module actually
 * being disabled.
 *
 * @see hook_disable()
 *
 * @param $modules
 *   An array of the disabled modules.
 */
function hook_modules_disabled($modules) {
  if (in_array('lousy_module', $modules)) {
    mymodule_enable_functionality();
  }
}

/**
 * Perform necessary actions after modules are uninstalled.
 *
 * This function differs from hook_uninstall() as it gives all other
 * modules a chance to perform actions when a module is uninstalled,
 * whereas hook_uninstall() will only be called on the module actually
 * being uninstalled.
 *
 * It is recommended that you implement this module if your module
 * stores data that may have been set by other modules.
 *
 * @see hook_uninstall()
 *
 * @param $modules
1514
 *   An array of the uninstalled modules.
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
 */
function hook_modules_uninstalled($modules) {
  foreach ($modules as $module) {
    db_delete('mymodule_table')
      ->condition('module', $module)
      ->execute();
  }
  mymodule_cache_rebuild();
}

1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
/**
 * Registers PHP stream wrapper implementations associated with a module.
 *
 * Provide a facility for managing and querying user-defined stream wrappers
 * in PHP. PHP's internal stream_get_wrappers() doesn't return the class
 * registered to handle a stream, which we need to be able to find the handler
 * for class instantiation.
 *
 * If a module registers a scheme that is already registered with PHP, it will
 * be unregistered and replaced with the specified class.
 *
 * @return
 *   A nested array, keyed first by scheme name ("public" for "public://"),
 *   then keyed by the following values:
 *   - 'name' A short string to name the wrapper.
 *   - 'class' A string specifying the PHP class that implements the
 *     DrupalStreamWrapperInterface interface.
 *   - 'description' A string with a short description of what the wrapper does.
1543
1544
1545
 *   - 'type' A bitmask of flags indicating what type of streams this wrapper
 *     will access - local or remote, readable and/or writeable, etc. Many
 *     shortcut constants are defined in stream_wrappers.inc. 
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
 *
 * @see file_get_stream_wrappers()
 * @see hook_stream_wrappers_alter()
 * @see system_stream_wrappers()
 */
function hook_stream_wrappers() {
  return array(
    'public' => array(
      'name' => t('Public files'),
      'class' => 'DrupalPublicStreamWrapper',
      'description' => t('Public local files served by the webserver.'),
    ),
    'private' => array(
      'name' => t('Private files'),
      'class' => 'DrupalPrivateStreamWrapper',
      'description' => t('Private local files served by Drupal.'),
    ),
    'temp' => array(
      'name' => t('Temporary files'),
      'class' => 'DrupalTempStreamWrapper',
      'description' => t('Temporary local files for upload and previews.'),
1567
      'type' => STREAM_WRAPPERS_HIDDEN,
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
    )
  );
}

/**
 * Alters the list of PHP stream wrapper implementations.
 *
 * @see file_get_stream_wrappers()
 * @see hook_stream_wrappers()
 */
function hook_stream_wrappers_alter(&$wrappers) {
  // Change the name of private files to reflect the performance.
  $wrappers['private']['name'] = t('Slow files');
}

1583
/**
1584
 * Load additional information into file objects.
1585
 *
1586
1587
 * file_load_multiple() calls this hook to allow modules to load
 * additional information into each file.
1588
 *
1589
1590
 * @param $files
 *   An array of file objects, indexed by fid.
1591
 *
1592
1593
 * @see file_load_multiple()
 * @see upload_file_load()
1594
 */
1595
function hook_file_load($files) {
1596
  // Add the upload specific data into the file object.
1597
1598
1599
1600
1601
  $result = db_query('SELECT * FROM {upload} u WHERE u.fid IN (:fids)', array(':fids' => array_keys($files)))->fetchAll(PDO::FETCH_ASSOC);
  foreach ($result as $record) {
    foreach ($record as $key => $value) {
      $files[$record['fid']]->$key = $value;
    }
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
  }
}

/**
 * Check that files meet a given criteria.
 *
 * This hook lets modules perform additional validation on files. They're able
 * to report a failure by returning one or more error messages.
 *
 * @param $file
 *   The file object being validated.
 * @return
 *   An array of error messages. If there are no problems with the file return
 *   an empty array.
 *
 * @see file_validate()
 */
function hook_file_validate(&$file) {
  $errors = array();

  if (empty($file->filename)) {
    $errors[] = t("The file's name is empty. Please give a name to the file.");
  }
  if (strlen($file->filename) > 255) {
    $errors[] = t("The file's name exceeds the 255 characters limit. Please rename the file and try again.");
  }

  return $errors;
}

/**
 * Respond to a file being added.
 *
 * This hook is called when a file has been added to the database. The hook
 * doesn't distinguish between files created as a result of a copy or those
 * created by an upload.
 *
 * @param $file
 *   The file that has just been created.
 *
 * @see file_save()
 */
function hook_file_insert(&$file) {

}

/**
 * Respond to a file being updated.
 *
 * This hook is called when file_save() is called on an existing file.
 *
 * @param $file
 *   The file that has just been updated.
 *
 * @see file_save()
 */
function hook_file_update(&$file) {

}

/**
 * Respond to a file that has been copied.
 *
 * @param $file
 *   The newly copied file object.
 * @param $source
 *   The original file before the copy.
 *
 * @see file_copy()
 */
function hook_file_copy($file, $source) {

}

/**
 * Respond to a file that has been moved.
 *
 * @param $file
 *   The updated file object after the move.
 * @param $source
 *   The original file object before the move.
 *
 * @see file_move()
 */
function hook_file_move($file, $source) {

}

/**
 * Report the number of times a file is referenced by a module.
 *
 * This hook is called to determine if a files is in use. Multiple modules may
 * be referencing the same file and to prevent one from deleting a file used by
 * another this hook is called.
 *
 * @param $file
 *   The file object being checked for references.
 * @return
 *   If the module uses this file return an array with the module name as the
 *   key and the value the number of times the file is used.
 *
 * @see file_delete()
 * @see upload_file_references()
 */
function hook_file_references($file) {
  // If upload.module is still using a file, do not let other modules delete it.
1708
  $file_used = (bool) db_query_range('SELECT 1 FROM {upload} WHERE fid = :fid', 0, 1, array(':fid' => $file->fid))->fetchField();
1709
  if ($file_used) {
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
    // Return the name of the module and how many references it has to the file.
    return array('upload' => $count);
  }
}

/**
 * Respond to a file being deleted.
 *
 * @param $file
 *   The file that has just been deleted.
 *
 * @see file_delete()
 * @see upload_file_delete()
 */
function hook_file_delete($file) {
  // Delete all information associated with the file.
  db_delete('upload')->condition('fid', $file->fid)->execute();
}

/**
 * Control access to private file downloads and specify HTTP headers.
 *
 * This hook allows modules enforce permissions on file downloads when the
 * private file download method is selected. Modules can also provide headers
 * to specify information like the file's name or MIME type.
 *
1736
1737
 * @param $uri
 *   The URI of the file.
1738
1739
1740
1741
1742
1743
1744
1745
1746
 * @return
 *   If the user does not have permission to access the file, return -1. If the
 *   user has permission, return an array with the appropriate headers. If the
 *   file is not controlled by the current module, the return value should be
 *   NULL.
 *
 * @see file_download()
 * @see upload_file_download()
 */
1747
function hook_file_download($uri) {
1748
  // Check if the file is controlled by the current module.
1749
1750
  if (!file_prepare_directory($uri)) {
    $uri = FALSE;
1751
  }
1752
  $result = db_query("SELECT f.* FROM {file} f INNER JOIN {upload} u ON f.fid = u.fid WHERE uri = :uri", array('uri' => $uri));
1753
  foreach ($result as $file) {
1754
1755
1756
1757
    if (!user_access('view uploaded files')) {
      return -1;
    }
    return array(
1758
1759
      'Content-Type' => $file->filemime,
      'Content-Length' => $file->filesize,
1760
1761
1762
1763
1764
    );
  }
}

/**
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
 * Alter the URL to a file.
 *
 * This hook is called from file_create_url(), and  is called fairly
 * frequently (10+ times per page), depending on how many files there are in a
 * given page.
 * If CSS and JS aggregation are disabled, this can become very frequently
 * (50+ times per page) so performance is critical.
 *
 * This function should alter the URI, if it wants to rewrite the file URL.
 *
 * @param $uri
 *   The URI to a file for which we need an external URL, or the path to a
 *   shipped file.
 */
function hook_file_url_alter(&$uri) {
  global $user;

  // User 1 will always see the local file in this example.
  if ($user->uid == 1) {
    return;
  }

  $cdn1 = 'http://cdn1.example.com';
  $cdn2 = 'http://cdn2.example.com';
  $cdn_extensions = array('css', 'js', 'gif', 'jpg', 'jpeg', 'png');

  // Most CDNs don't support private file transfers without a lot of hassle,
  // so don't support this in the common case.
  $schemes = array('public');

  $scheme = file_uri_scheme($uri);

  // Only serve shipped files and public created files from the CDN.
  if (!$scheme || in_array($scheme, $schemes)) {
    // Shipped files.
    if (!$scheme) {
      $path = $uri;
    }
    // Public created files.
    else {
      $wrapper = file_stream_wrapper_get_instance_by_scheme($scheme);
      $path = $wrapper->getDirectoryPath() . '/' . file_uri_target($uri);
    }

    // Clean up Windows paths.
    $path = str_replace('\\', '/', $path);

    // Serve files with one of the CDN extensions from CDN 1, all others from
    // CDN 2.
    $pathinfo = pathinfo($path);
    if (array_key_exists('extension', $pathinfo) && in_array($pathinfo['extension'], $cdn_extensions)) {
      $uri = $cdn1 . '/' . $path;
    }
    else {
      $uri = $cdn2 . '/' . $path;
    }
  }
}
                                                                                                      /**
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
 * Check installation requirements and do status reporting.
 *
 * This hook has two closely related uses, determined by the $phase argument:
 * checking installation requirements ($phase == 'install')
 * and status reporting ($phase == 'runtime').
 *
 * Note that this hook, like all others dealing with installation and updates,
 * must reside in a module_name.install file, or it will not properly abort
 * the installation of the module if a critical requirement is missing.
 *
 * During the 'install' phase, modules can for example assert that
 * library or server versions are available or sufficient.
 * Note that the installation of a module can happen during installation of
 * Drupal itself (by install.php) with an installation profile or later by hand.
 * As a consequence, install-time requirements must be checked without access
 * to the full Drupal API, because it is not available during install.php.
1840
1841
 * For localization you should for example use $t = get_t() to
 * retrieve the appropriate localization function name (t() or st()).
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
 * If a requirement has a severity of REQUIREMENT_ERROR, install.php will abort
 * or at least the module will not install.
 * Other severity levels have no effect on the installation.
 * Module dependencies do not belong to these installation requirements,
 * but should be defined in the module's .info file.
 *
 * The 'runtime' phase is not limited to pure installation requirements
 * but can also be used for more general status information like maintenance
 * tasks and security issues.
 * The returned 'requirements' will be listed on the status report in the
 * administration section, with indication of the severity level.
 * Moreover, any requirement with a severity of REQUIREMENT_ERROR severity will
 * result in a notice on the the administration overview page.
 *
 * @param $phase
 *   The phase in which hook_requirements is run:
 *   - 'install': the module is being installed.
 *   - 'runtime': the runtime requirements are being checked and shown on the
 *              status report page.
 *
 * @return
 *   A keyed array of requirements. Each requirement is itself an array with
 *   the following items:
 *     - 'title': the name of the requirement.
 *     - 'value': the current value (e.g. version, time, level, ...). During
 *       install phase, this should only be used for version numbers, do not set
 *       it if not applicable.
 *     - 'description': description of the requirement/status.
 *     - 'severity': the requirement's result/severity level, one of:
 *         - REQUIREMENT_INFO:    For info only.
 *         - REQUIREMENT_OK:      The requirement is satisfied.
 *         - REQUIREMENT_WARNING: The requirement failed with a warning.
 *         - REQUIREMENT_ERROR:   The requirement failed with an error.
 */
function hook_requirements($phase) {
  $requirements = array();
  // Ensure translations don't break at install time
  $t = get_t();

  // Report Drupal version
  if ($phase == 'runtime') {
    $requirements['drupal'] = array(
      'title' => $t('Drupal'),
      'value' => VERSION,
      'severity' => REQUIREMENT_INFO
    );
  }

  // Test PHP version
  $requirements['php'] = array(
    'title' => $t('PHP'),
    'value' => ($phase == 'runtime') ? l(phpversion(), 'admin/logs/status/php') : phpversion(),
  );
  if (version_compare(phpversion(), DRUPAL_MINIMUM_PHP) < 0) {
    $requirements['php']['description'] = $t('Your PHP installation is too old. Drupal requires at least PHP %version.', array('%version' => DRUPAL_MINIMUM_PHP));
    $requirements['php']['severity'] = REQUIREMENT_ERROR;
  }

  // Report cron status
  if ($phase == 'runtime') {
1902
    $cron_last = variable_get('cron_last');
1903
1904
1905
1906
1907
1908

    if (is_numeric($cron_last)) {
      $requirements['cron']['value'] = $t('Last run !time ago', array('!time' => format_interval(REQUEST_TIME - $cron_last)));
    }
    else {
      $requirements['cron'] = array(
1909
        'description' => $t('Cron has not run. It appears cron jobs have not been setup on your system. Check the help pages for <a href="@url">configuring cron jobs</a>.', array('@url' => 'http://drupal.org/cron')),
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
        'severity' => REQUIREMENT_ERROR,
        'value' => $t('Never run'),
      );
    }

    $requirements['cron']['description'] .= ' ' . t('You can <a href="@cron">run cron manually</a>.', array('@cron' => url('admin/logs/status/run-cron')));

    $requirements['cron']['title'] = $t('Cron maintenance tasks');
  }

  return $requirements;
}

/**
 * Define the current version of the database schema.
 *
 * A Drupal schema definition is an array structure representing one or
 * more tables and their related keys and indexes. A schema is defined by
 * hook_schema() which must live in your module's .install file.
 *
 * By implementing hook_schema() and specifying the tables your module
 * declares, you can easily create and drop these tables on all
 * supported database engines. You don't have to deal with the
 * different SQL dialects for table creation and alteration of the
 * supported database engines.
 *
 * See the Schema API Handbook at http://drupal.org/node/146843 for
 * details on schema definition structures.
 *
 * @return
1940
 * A schema definition structure array. For each element of the
1941
1942
1943
1944
1945
1946
 * array, the key is a table name and the value is a table structure
 * definition.
 */
function hook_schema() {
  $schema['node'] = array(
    // example (partial) specification for table "node"
1947
    'description' => 'The base table for nodes.',
1948
1949
    'fields' => array(
      'nid' => array(
1950
        'description' => 'The primary identifier for a node.',
1951
1952
1953
1954
        'type' => 'serial',
        'unsigned' => TRUE,
        'not null' => TRUE),
      'vid' => array(