forked from Elgg/Elgg
-
Notifications
You must be signed in to change notification settings - Fork 0
/
elgglib.php
2260 lines (1999 loc) · 62.8 KB
/
elgglib.php
1
2
3
4
5
6
7
8
9
10
11
12
13
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
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
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
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
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
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
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
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
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
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
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
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
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<?php
/**
* Bootstrapping and helper procedural code available for use in Elgg core and plugins.
*
* @package Elgg.Core
* @todo These functions can't be subpackaged because they cover a wide mix of
* purposes and subsystems. Many of them should be moved to more relevant files.
*/
// prep core classes to be autoloadable
spl_autoload_register('_elgg_autoload');
elgg_register_classes(dirname(dirname(__FILE__)) . '/classes');
/**
* Autoload classes
*
* @param string $class The name of the class
*
* @return void
* @throws Exception
* @access private
*/
function _elgg_autoload($class) {
global $CONFIG;
if (!isset($CONFIG->classes[$class]) || !include($CONFIG->classes[$class])) {
return false;
}
}
/**
* Register all files found in $dir as classes
* Need to be named MyClass.php
*
* @param string $dir The dir to look in
*
* @return void
* @since 1.8.0
*/
function elgg_register_classes($dir) {
$classes = elgg_get_file_list($dir, array(), array(), array('.php'));
foreach ($classes as $class) {
elgg_register_class(basename($class, '.php'), $class);
}
}
/**
* Register a classname to a file.
*
* @param string $class The name of the class
* @param string $location The location of the file
*
* @return true
* @since 1.8.0
*/
function elgg_register_class($class, $location) {
global $CONFIG;
if (!isset($CONFIG->classes)) {
$CONFIG->classes = array();
}
$CONFIG->classes[$class] = $location;
return true;
}
/**
* Register a php library.
*
* @param string $name The name of the library
* @param string $location The location of the file
*
* @return void
* @since 1.8.0
*/
function elgg_register_library($name, $location) {
global $CONFIG;
if (!isset($CONFIG->libraries)) {
$CONFIG->libraries = array();
}
$CONFIG->libraries[$name] = $location;
}
/**
* Load a php library.
*
* @param string $name The name of the library
*
* @return void
* @throws InvalidParameterException
* @since 1.8.0
*/
function elgg_load_library($name) {
global $CONFIG;
if (!isset($CONFIG->libraries)) {
$CONFIG->libraries = array();
}
if (!isset($CONFIG->libraries[$name])) {
$error = elgg_echo('InvalidParameterException:LibraryNotRegistered', array($name));
throw new InvalidParameterException($error);
}
if (!include_once($CONFIG->libraries[$name])) {
$error = elgg_echo('InvalidParameterException:LibraryNotFound', array(
$name,
$CONFIG->libraries[$name])
);
throw new InvalidParameterException($error);
}
}
/**
* Forward to $location.
*
* Sends a 'Location: $location' header and exists. If headers have
* already been sent, returns FALSE.
*
* @param string $location URL to forward to browser to. Can be path relative to the network's URL.
* @param string $reason Short explanation for why we're forwarding
*
* @return False False if headers have been sent. Terminates execution if forwarding.
*/
function forward($location = "", $reason = 'system') {
global $CONFIG;
if (!headers_sent()) {
if ($location === REFERER) {
$location = $_SERVER['HTTP_REFERER'];
}
$location = elgg_normalize_url($location);
// return new forward location or false to stop the forward or empty string to exit
$current_page = current_page_url();
$params = array('current_url' => $current_page, 'forward_url' => $location);
$location = elgg_trigger_plugin_hook('forward', $reason, $params, $location);
if ($location) {
header("Location: {$location}");
exit;
} else if ($location === '') {
exit;
}
} else {
throw new SecurityException(elgg_echo('SecurityException:ForwardFailedToRedirect'));
}
}
/**
* Register a JavaScript file for inclusion
*
* This function handles adding JavaScript to a web page. If multiple
* calls are made to register the same JavaScript file based on the $id
* variable, only the last file is included. This allows a plugin to add
* JavaScript from a view that may be called more than once. It also handles
* more than one plugin adding the same JavaScript.
*
* jQuery plugins often have filenames such as jquery.rating.js. A best practice
* is to base $name on the filename: "jquery.rating". It is recommended to not
* use version numbers in the name.
*
* The JavaScript files can be local to the server or remote (such as
* Google's CDN).
*
* @param string $name An identifier for the JavaScript library
* @param string $url URL of the JavaScript file
* @param string $location Page location: head or footer. (default: head)
* @param int $priority Priority of the JS file (lower numbers load earlier)
*
* @return bool
* @since 1.8.0
*/
function elgg_register_js($name, $url, $location = 'head', $priority = null) {
return elgg_register_external_file('js', $name, $url, $location, $priority);
}
/**
* Unregister a JavaScript file
*
* @param string $name The identifier for the JavaScript library
*
* @return bool
* @since 1.8.0
*/
function elgg_unregister_js($name) {
return elgg_unregister_external_file('js', $name);
}
/**
* Load a JavaScript resource on this page
*
* This must be called before elgg_view_page(). It can be called before the
* script is registered. If you do not want a script loaded, unregister it.
*
* @param string $name Identifier of the JavaScript resource
*
* @return void
* @since 1.8.0
*/
function elgg_load_js($name) {
elgg_load_external_file('js', $name);
}
/**
* Get the JavaScript URLs that are loaded
*
* @param string $location 'head' or 'footer'
*
* @return array
* @since 1.8.0
*/
function elgg_get_loaded_js($location = 'head') {
return elgg_get_loaded_external_files('js', $location);
}
/**
* Register a CSS file for inclusion in the HTML head
*
* @param string $name An identifier for the CSS file
* @param string $url URL of the CSS file
* @param int $priority Priority of the CSS file (lower numbers load earlier)
*
* @return bool
* @since 1.8.0
*/
function elgg_register_css($name, $url, $priority = null) {
return elgg_register_external_file('css', $name, $url, 'head', $priority);
}
/**
* Unregister a CSS file
*
* @param string $name The identifier for the CSS file
*
* @return bool
* @since 1.8.0
*/
function elgg_unregister_css($name) {
return elgg_unregister_external_file('css', $name);
}
/**
* Load a CSS file for this page
*
* This must be called before elgg_view_page(). It can be called before the
* CSS file is registered. If you do not want a CSS file loaded, unregister it.
*
* @param string $name Identifier of the CSS file
*
* @return void
* @since 1.8.0
*/
function elgg_load_css($name) {
elgg_load_external_file('css', $name);
}
/**
* Get the loaded CSS URLs
*
* @return array
* @since 1.8.0
*/
function elgg_get_loaded_css() {
return elgg_get_loaded_external_files('css', 'head');
}
/**
* Core registration function for external files
*
* @param string $type Type of external resource (js or css)
* @param string $name Identifier used as key
* @param string $url URL
* @param string $location Location in the page to include the file
* @param int $priority Loading priority of the file
*
* @return bool
* @since 1.8.0
*/
function elgg_register_external_file($type, $name, $url, $location, $priority = 500) {
global $CONFIG;
if (empty($name) || empty($url)) {
return false;
}
$url = elgg_format_url($url);
$url = elgg_normalize_url($url);
elgg_bootstrap_externals_data_structure($type);
$name = trim(strtolower($name));
// normalize bogus priorities, but allow empty, null, and false to be defaults.
if (!is_numeric($priority)) {
$priority = 500;
}
// no negative priorities right now.
$priority = max((int)$priority, 0);
$item = elgg_extract($name, $CONFIG->externals_map[$type]);
if ($item) {
// updating a registered item
// don't update loaded because it could already be set
$item->url = $url;
$item->location = $location;
// if loaded before registered, that means it hasn't been added to the list yet
if ($CONFIG->externals[$type]->contains($item)) {
$priority = $CONFIG->externals[$type]->move($item, $priority);
} else {
$priority = $CONFIG->externals[$type]->add($item, $priority);
}
} else {
$item = new stdClass();
$item->loaded = false;
$item->url = $url;
$item->location = $location;
$priority = $CONFIG->externals[$type]->add($item, $priority);
}
$CONFIG->externals_map[$type][$name] = $item;
return $priority !== false;
}
/**
* Unregister an external file
*
* @param string $type Type of file: js or css
* @param string $name The identifier of the file
*
* @return bool
* @since 1.8.0
*/
function elgg_unregister_external_file($type, $name) {
global $CONFIG;
elgg_bootstrap_externals_data_structure($type);
$name = trim(strtolower($name));
$item = elgg_extract($name, $CONFIG->externals_map[$type]);
if ($item) {
unset($CONFIG->externals_map[$type][$name]);
return $CONFIG->externals[$type]->remove($item);
}
return false;
}
/**
* Load an external resource for use on this page
*
* @param string $type Type of file: js or css
* @param string $name The identifier for the file
*
* @return void
* @since 1.8.0
*/
function elgg_load_external_file($type, $name) {
global $CONFIG;
elgg_bootstrap_externals_data_structure($type);
$name = trim(strtolower($name));
$item = elgg_extract($name, $CONFIG->externals_map[$type]);
if ($item) {
// update a registered item
$item->loaded = true;
} else {
$item = new stdClass();
$item->loaded = true;
$item->url = '';
$item->location = '';
$priority = $CONFIG->externals[$type]->add($item);
$CONFIG->externals_map[$type][$name] = $item;
}
}
/**
* Get external resource descriptors
*
* @param string $type Type of file: js or css
* @param string $location Page location
*
* @return array
* @since 1.8.0
*/
function elgg_get_loaded_external_files($type, $location) {
global $CONFIG;
if (isset($CONFIG->externals) && $CONFIG->externals[$type] instanceof ElggPriorityList) {
$items = $CONFIG->externals[$type]->getElements();
$callback = "return \$v->loaded == true && \$v->location == '$location';";
$items = array_filter($items, create_function('$v', $callback));
if ($items) {
array_walk($items, create_function('&$v,$k', '$v = $v->url;'));
}
return $items;
}
return array();
}
/**
* Bootstraps the externals data structure in $CONFIG.
*
* @param string $type The type of external, js or css.
* @access private
*/
function elgg_bootstrap_externals_data_structure($type) {
global $CONFIG;
if (!isset($CONFIG->externals)) {
$CONFIG->externals = array();
}
if (!isset($CONFIG->externals[$type]) || !$CONFIG->externals[$type] instanceof ElggPriorityList) {
$CONFIG->externals[$type] = new ElggPriorityList();
}
if (!isset($CONFIG->externals_map)) {
$CONFIG->externals_map = array();
}
if (!isset($CONFIG->externals_map[$type])) {
$CONFIG->externals_map[$type] = array();
}
}
/**
* Returns a list of files in $directory.
*
* Only returns files. Does not recurse into subdirs.
*
* @param string $directory Directory to look in
* @param array $exceptions Array of filenames to ignore
* @param array $list Array of files to append to
* @param mixed $extensions Array of extensions to allow, NULL for all. Use a dot: array('.php').
*
* @return array Filenames in $directory, in the form $directory/filename.
*/
function elgg_get_file_list($directory, $exceptions = array(), $list = array(),
$extensions = NULL) {
$directory = sanitise_filepath($directory);
if ($handle = opendir($directory)) {
while (($file = readdir($handle)) !== FALSE) {
if (!is_file($directory . $file) || in_array($file, $exceptions)) {
continue;
}
if (is_array($extensions)) {
if (in_array(strrchr($file, '.'), $extensions)) {
$list[] = $directory . $file;
}
} else {
$list[] = $directory . $file;
}
}
closedir($handle);
}
return $list;
}
/**
* Sanitise file paths ensuring that they begin and end with slashes etc.
*
* @param string $path The path
* @param bool $append_slash Add tailing slash
*
* @return string
*/
function sanitise_filepath($path, $append_slash = TRUE) {
// Convert to correct UNIX paths
$path = str_replace('\\', '/', $path);
$path = str_replace('../', '/', $path);
// replace // with / except when preceeded by :
$path = preg_replace("/([^:])\/\//", "$1/", $path);
// Sort trailing slash
$path = trim($path);
// rtrim defaults plus /
$path = rtrim($path, " \n\t\0\x0B/");
if ($append_slash) {
$path = $path . '/';
}
return $path;
}
/**
* Queues a message to be displayed.
*
* Messages will not be displayed immediately, but are stored in
* for later display, usually upon next page load.
*
* The method of displaying these messages differs depending upon plugins and
* viewtypes. The core default viewtype retrieves messages in
* {@link views/default/page/shells/default.php} and displays messages as
* javascript popups.
*
* @internal Messages are stored as strings in the $_SESSION['msg'][$register] array.
*
* @warning This function is used to both add to and clear the message
* stack. If $messages is null, $register will be returned and cleared.
* If $messages is null and $register is empty, all messages will be
* returned and removed.
*
* @important This function handles the standard {@link system_message()} ($register =
* 'messages') as well as {@link register_error()} messages ($register = 'errors').
*
* @param mixed $message Optionally, a single message or array of messages to add, (default: null)
* @param string $register Types of message: "error", "success" (default: success)
* @param bool $count Count the number of messages (default: false)
*
* @return true|false|array Either the array of messages, or a response regarding
* whether the message addition was successful.
* @todo Clean up. Separate registering messages and retrieving them.
*/
function system_messages($message = null, $register = "success", $count = false) {
if (!isset($_SESSION['msg'])) {
$_SESSION['msg'] = array();
}
if (!isset($_SESSION['msg'][$register]) && !empty($register)) {
$_SESSION['msg'][$register] = array();
}
if (!$count) {
if (!empty($message) && is_array($message)) {
$_SESSION['msg'][$register] = array_merge($_SESSION['msg'][$register], $message);
return true;
} else if (!empty($message) && is_string($message)) {
$_SESSION['msg'][$register][] = $message;
return true;
} else if (is_null($message)) {
if ($register != "") {
$returnarray = array();
$returnarray[$register] = $_SESSION['msg'][$register];
$_SESSION['msg'][$register] = array();
} else {
$returnarray = $_SESSION['msg'];
$_SESSION['msg'] = array();
}
return $returnarray;
}
} else {
if (!empty($register)) {
return sizeof($_SESSION['msg'][$register]);
} else {
$count = 0;
foreach ($_SESSION['msg'] as $register => $submessages) {
$count += sizeof($submessages);
}
return $count;
}
}
return false;
}
/**
* Counts the number of messages, either globally or in a particular register
*
* @param string $register Optionally, the register
*
* @return integer The number of messages
*/
function count_messages($register = "") {
return system_messages(null, $register, true);
}
/**
* Display a system message on next page load.
*
* @see system_messages()
*
* @param string|array $message Message or messages to add
*
* @return bool
*/
function system_message($message) {
return system_messages($message, "success");
}
/**
* Display an error on next page load.
*
* @see system_messages()
*
* @param string|array $error Error or errors to add
*
* @return bool
*/
function register_error($error) {
return system_messages($error, "error");
}
/**
* Register a callback as an Elgg event handler.
*
* Events are emitted by Elgg when certain actions occur. Plugins
* can respond to these events or halt them completely by registering a handler
* as a callback to an event. Multiple handlers can be registered for
* the same event and will be executed in order of $priority. Any handler
* returning false will halt the execution chain.
*
* This function is called with the event name, event type, and handler callback name.
* Setting the optional $priority allows plugin authors to specify when the
* callback should be run. Priorities for plugins should be 1-1000.
*
* The callback is passed 3 arguments when called: $event, $type, and optional $params.
*
* $event is the name of event being emitted.
* $type is the type of event or object concerned.
* $params is an optional parameter passed that can include a related object. See
* specific event documentation for details on which events pass what parameteres.
*
* @tip If a priority isn't specified it is determined by the order the handler was
* registered relative to the event and type. For plugins, this generally means
* the earlier the plugin is in the load order, the earlier the priorities are for
* any event handlers.
*
* @tip $event and $object_type can use the special keyword 'all'. Handler callbacks registered
* with $event = all will be called for all events of type $object_type. Similarly,
* callbacks registered with $object_type = all will be called for all events of type
* $event, regardless of $object_type. If $event and $object_type both are 'all', the
* handler callback will be called for all events.
*
* @tip Event handler callbacks are considered in the follow order:
* - Specific registration where 'all' isn't used.
* - Registration where 'all' is used for $event only.
* - Registration where 'all' is used for $type only.
* - Registration where 'all' is used for both.
*
* @warning If you use the 'all' keyword, you must have logic in the handler callback to
* test the passed parameters before taking an action.
*
* @tip When referring to events, the preferred syntax is "event, type".
*
* @internal Events are stored in $CONFIG->events as:
* <code>
* $CONFIG->events[$event][$type][$priority] = $callback;
* </code>
*
* @param string $event The event type
* @param string $object_type The object type
* @param string $callback The handler callback
* @param int $priority The priority - 0 is default, negative before, positive after
*
* @return bool
* @link http://docs.elgg.org/Tutorials/Plugins/Events
* @example events/basic.php Basic example of registering an event handler callback.
* @example events/advanced.php Advanced example of registering an event handler
* callback and halting execution.
* @example events/all.php Example of how to use the 'all' keyword.
*/
function elgg_register_event_handler($event, $object_type, $callback, $priority = 500) {
global $CONFIG;
if (empty($event) || empty($object_type)) {
return FALSE;
}
if (!isset($CONFIG->events)) {
$CONFIG->events = array();
}
if (!isset($CONFIG->events[$event])) {
$CONFIG->events[$event] = array();
}
if (!isset($CONFIG->events[$event][$object_type])) {
$CONFIG->events[$event][$object_type] = array();
}
if (!is_callable($callback)) {
return FALSE;
}
$priority = max((int) $priority, 0);
while (isset($CONFIG->events[$event][$object_type][$priority])) {
$priority++;
}
$CONFIG->events[$event][$object_type][$priority] = $callback;
ksort($CONFIG->events[$event][$object_type]);
return TRUE;
}
/**
* Unregisters a callback for an event.
*
* @param string $event The event type
* @param string $object_type The object type
* @param string $callback The callback
*
* @return void
* @since 1.7
*/
function elgg_unregister_event_handler($event, $object_type, $callback) {
global $CONFIG;
foreach ($CONFIG->events[$event][$object_type] as $key => $event_callback) {
if ($event_callback == $callback) {
unset($CONFIG->events[$event][$object_type][$key]);
}
}
}
/**
* Trigger an Elgg Event and run all handler callbacks registered to that event, type.
*
* This function runs all handlers registered to $event, $object_type or
* the special keyword 'all' for either or both.
*
* $event is usually a verb: create, update, delete, annotation.
*
* $object_type is usually a noun: object, group, user, annotation, relationship, metadata.
*
* $object is usually an Elgg* object assciated with the event.
*
* @warning Elgg events should only be triggered by core. Plugin authors should use
* {@link trigger_elgg_plugin_hook()} instead.
*
* @tip When referring to events, the preferred syntax is "event, type".
*
* @internal Only rarely should events be changed, added, or removed in core.
* When making changes to events, be sure to first create a ticket in trac.
*
* @internal @tip Think of $object_type as the primary namespace element, and
* $event as the secondary namespace.
*
* @param string $event The event type
* @param string $object_type The object type
* @param string $object The object involved in the event
*
* @return bool The result of running all handler callbacks.
* @link http://docs.elgg.org/Tutorials/Core/Events
* @internal @example events/emit.php Basic emitting of an Elgg event.
*/
function elgg_trigger_event($event, $object_type, $object = null) {
global $CONFIG;
$events = array();
if (isset($CONFIG->events[$event][$object_type])) {
$events[] = $CONFIG->events[$event][$object_type];
}
if (isset($CONFIG->events['all'][$object_type])) {
$events[] = $CONFIG->events['all'][$object_type];
}
if (isset($CONFIG->events[$event]['all'])) {
$events[] = $CONFIG->events[$event]['all'];
}
if (isset($CONFIG->events['all']['all'])) {
$events[] = $CONFIG->events['all']['all'];
}
$args = array($event, $object_type, $object);
foreach ($events as $callback_list) {
if (is_array($callback_list)) {
foreach ($callback_list as $callback) {
if (call_user_func_array($callback, $args) === FALSE) {
return FALSE;
}
}
}
}
return TRUE;
}
/**
* Register a callback as a plugin hook handler.
*
* Plugin hooks allow developers to losely couple plugins and features by
* repsonding to and emitting {@link elgg_trigger_plugin_hook()} customizable hooks.
* Handler callbacks can respond to the hook, change the details of the hook, or
* ignore it.
*
* Multiple handlers can be registered for a plugin hook, and each callback
* is called in order of priority. If the return value of a handler is not
* null, that value is passed to the next callback in the call stack. When all
* callbacks have been run, the final value is passed back to the caller
* via {@link elgg_trigger_plugin_hook()}.
*
* Similar to Elgg Events, plugin hook handler callbacks are registered by passing
* a hook, a type, and a priority.
*
* The callback is passed 4 arguments when called: $hook, $type, $value, and $params.
*
* - str $hook The name of the hook.
* - str $type The type of hook.
* - mixed $value The return value of the last handler or the default
* value if no other handlers have been called.
* - mixed $params An optional array of parameters. Used to provide additional
* information to plugins.
*
* @internal Plugin hooks are stored in $CONFIG->hooks as:
* <code>
* $CONFIG->hooks[$hook][$type][$priority] = $callback;
* </code>
*
* @tip Plugin hooks are similar to Elgg Events in that Elgg emits
* a plugin hook when certain actions occur, but a plugin hook allows you to alter the
* parameters, as well as halt execution.
*
* @tip If a priority isn't specified it is determined by the order the handler was
* registered relative to the event and type. For plugins, this generally means
* the earlier the plugin is in the load order, the earlier the priorities are for
* any event handlers.
*
* @tip Like Elgg Events, $hook and $type can use the special keyword 'all'.
* Handler callbacks registered with $hook = all will be called for all hooks
* of type $type. Similarly, handlers registered with $type = all will be
* called for all hooks of type $event, regardless of $object_type. If $hook
* and $type both are 'all', the handler will be called for all hooks.
*
* @tip Plugin hooks are sometimes used to gather lists from plugins. This is
* usually done by pushing elements into an array passed in $params. Be sure
* to append to and then return $value so you don't overwrite other plugin's
* values.
*
* @warning Unlike Elgg Events, a handler that returns false will NOT halt the
* execution chain.
*
* @param string $hook The name of the hook
* @param string $type The type of the hook
* @param callback $callback The name of a valid function or an array with object and method
* @param int $priority The priority - 500 is default, lower numbers called first
*
* @return bool
*
* @example hooks/register/basic.php Registering for a plugin hook and examining the variables.
* @example hooks/register/advanced.php Registering for a plugin hook and changing the params.
* @link http://docs.elgg.org/Tutorials/Plugins/Hooks
* @since 1.8.0
*/
function elgg_register_plugin_hook_handler($hook, $type, $callback, $priority = 500) {
global $CONFIG;
if (empty($hook) || empty($type)) {
return FALSE;
}
if (!isset($CONFIG->hooks)) {
$CONFIG->hooks = array();
}
if (!isset($CONFIG->hooks[$hook])) {
$CONFIG->hooks[$hook] = array();
}
if (!isset($CONFIG->hooks[$hook][$type])) {
$CONFIG->hooks[$hook][$type] = array();
}
if (!is_callable($callback)) {
return FALSE;
}
$priority = max((int) $priority, 0);
while (isset($CONFIG->hooks[$hook][$type][$priority])) {
$priority++;
}
$CONFIG->hooks[$hook][$type][$priority] = $callback;
ksort($CONFIG->hooks[$hook][$type]);
return TRUE;
}
/**
* Unregister a callback as a plugin hook.
*
* @param string $hook The name of the hook
* @param string $entity_type The name of the type of entity (eg "user", "object" etc)
* @param callback $callback The PHP callback to be removed
*
* @return void
* @since 1.8.0
*/
function elgg_unregister_plugin_hook_handler($hook, $entity_type, $callback) {
global $CONFIG;
foreach ($CONFIG->hooks[$hook][$entity_type] as $key => $hook_callback) {
if ($hook_callback == $callback) {
unset($CONFIG->hooks[$hook][$entity_type][$key]);
}
}
}
/**
* Trigger a Plugin Hook and run all handler callbacks registered to that hook:type.
*
* This function runs all handlers regsitered to $hook, $type or
* the special keyword 'all' for either or both.
*
* Use $params to send additional information to the handler callbacks.
*
* $returnvalue Is the initial value to pass to the handlers, which can
* then change it. It is useful to use $returnvalue to set defaults.
* If no handlers are registered, $returnvalue is immediately returned.
*
* $hook is usually a verb: import, get_views, output.
*
* $type is usually a noun: user, ecml, page.
*
* @tip Like Elgg Events, $hook and $type can use the special keyword 'all'.
* Handler callbacks registered with $hook = all will be called for all hooks
* of type $type. Similarly, handlers registered with $type = all will be
* called for all hooks of type $event, regardless of $object_type. If $hook
* and $type both are 'all', the handler will be called for all hooks.
*
* @internal The checks for $hook and/or $type not being equal to 'all' is to
* prevent a plugin hook being registered with an 'all' being called more than
* once if the trigger occurs with an 'all'. An example in core of this is in
* actions.php:
* elgg_trigger_plugin_hook('action_gatekeeper:permissions:check', 'all', ...)
*
* @see elgg_register_plugin_hook_handler()
*
* @param string $hook The name of the hook to trigger ("all" will
* trigger for all $types regardless of $hook value)
* @param string $type The type of the hook to trigger ("all" will
* trigger for all $hooks regardless of $type value)
* @param mixed $params Additional parameters to pass to the handlers
* @param mixed $returnvalue An initial return value
*
* @return mixed|null The return value of the last handler callback called
*
* @example hooks/trigger/basic.php Trigger a hook that determins if execution
* should continue.
* @example hooks/trigger/advanced.php Trigger a hook with a default value and use
* the results to populate a menu.
* @example hooks/basic.php Trigger and respond to a basic plugin hook.
* @link http://docs.elgg.org/Tutorials/Plugins/Hooks
*
* @since 1.8.0
*/
function elgg_trigger_plugin_hook($hook, $type, $params = null, $returnvalue = null) {
global $CONFIG;
$hooks = array();
if (isset($CONFIG->hooks[$hook][$type])) {
if ($hook != 'all' && $type != 'all') {
$hooks[] = $CONFIG->hooks[$hook][$type];
}
}
if (isset($CONFIG->hooks['all'][$type])) {
if ($type != 'all') {
$hooks[] = $CONFIG->hooks['all'][$type];
}
}
if (isset($CONFIG->hooks[$hook]['all'])) {
if ($hook != 'all') {
$hooks[] = $CONFIG->hooks[$hook]['all'];
}
}
if (isset($CONFIG->hooks['all']['all'])) {
$hooks[] = $CONFIG->hooks['all']['all'];
}
foreach ($hooks as $callback_list) {
if (is_array($callback_list)) {
foreach ($callback_list as $hookcallback) {
$args = array($hook, $type, $returnvalue, $params);
$temp_return_value = call_user_func_array($hookcallback, $args);
if (!is_null($temp_return_value)) {
$returnvalue = $temp_return_value;
}
}
}
}
return $returnvalue;
}
/**
* Intercepts, logs, and displays uncaught exceptions.
*
* @warning This function should never be called directly.
*
* @see http://www.php.net/set-exception-handler
*
* @param Exception $exception The exception being handled
*
* @return void
* @access private
*/
function _elgg_php_exception_handler($exception) {
$timestamp = time();
error_log("Exception #$timestamp: $exception");