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[moodle.git] / tag / lib.php
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6bfe7aac 1<?php
4d4dac81 2
000ebd5c
DM
3// This file is part of Moodle - http://moodle.org/
4//
5// Moodle is free software: you can redistribute it and/or modify
6// it under the terms of the GNU General Public License as published by
7// the Free Software Foundation, either version 3 of the License, or
8// (at your option) any later version.
9//
10// Moodle is distributed in the hope that it will be useful,
11// but WITHOUT ANY WARRANTY; without even the implied warranty of
12// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13// GNU General Public License for more details.
14//
15// You should have received a copy of the GNU General Public License
16// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
17
c933a060 18/**
4a0daed7 19 * Moodle tag library
db32b054 20 *
986dca60 21 * Tag strings : you can use any character in tags, except the comma (which is
22 * the separator) and the '\' (backslash). Note that many spaces (or other
23 * blank characters) will get "compressed" into one. A tag string is always a
4a0daed7 24 * rawurlencode'd string. This is the same behavior as http://del.icio.us.
db32b054 25 *
986dca60 26 * A "record" is a php array (note that an object will work too) that contains
27 * the following variables :
db32b054 28 * - type: the table containing the record that we are tagging (eg: for a
29 * blog, this is table 'post', and for a user it is 'user')
986dca60 30 * - id: the id of the record
d4be9d6d 31 *
986dca60 32 * TODO: turn this into a full-fledged categorization system. This could start
33 * by modifying (removing, probably) the 'tag type' to use another table
34 * describing the relationship between tags (parents, sibling, etc.), which
db32b054 35 * could then be merged with the 'course categorization' system...
c933a060 36 *
986dca60 37 * BASIC INSTRUCTIONS :
38 * - to "tag a blog post" (for example):
4a0daed7 39 * tag_set('post', $blog_post->id, $array_of_tags);
d4be9d6d 40 *
db32b054 41 * - to "remove all the tags on a blog post":
4a0daed7 42 * tag_set('post', $blog_post->id, array());
43 *
44 * Tag set will create tags that need to be created.
d4be9d6d 45 *
000ebd5c 46 * @package core
4a0daed7 47 * @subpackage tag
48 * @see http://www.php.net/manual/en/function.urlencode.php
000ebd5c
DM
49 * @copyright 2007 Luiz Cruz <luiz.laydner@gmail.com>
50 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
c933a060 51 */
52
db32b054 53define('TAG_RETURN_ARRAY', 0);
54define('TAG_RETURN_OBJECT', 1);
55define('TAG_RETURN_TEXT', 2);
56define('TAG_RETURN_HTML', 3);
c933a060 57
db32b054 58define('TAG_CASE_LOWER', 0);
59define('TAG_CASE_ORIGINAL', 1);
d4be9d6d 60
537aa65c 61define('TAG_RELATED_ALL', 0);
62define('TAG_RELATED_MANUAL', 1);
63define('TAG_RELATED_CORRELATED', 2);
64
db32b054 65///////////////////////////////////////////////////////
66/////////////////// PUBLIC TAG API ////////////////////
c933a060 67
8479c2e0 68/// Functions for settings tags //////////////////////
69
c933a060 70/**
8479c2e0 71 * Set the tags assigned to a record. This overwrites the current tags.
986dca60 72 *
73 * This function is meant to be fed the string coming up from the user
8479c2e0 74 * interface, which contains all tags assigned to a record.
75 *
986dca60 76 * @param string $record_type the type of record to tag ('post' for blogs,
8479c2e0 77 * 'user' for users, 'tag' for tags, etc.
78 * @param int $record_id the id of the record to tag
986dca60 79 * @param array $tags the array of tags to set on the record. If
8479c2e0 80 * given an empty array, all tags will be removed.
986dca60 81 * @return void
c933a060 82 */
b91de8a5 83function tag_set($record_type, $record_id, $tags) {
3d436d8a 84
28f64040 85 static $in_recursion_semaphore = false; // this is to prevent loops when tagging a tag
86 if ( $record_type == 'tag' && !$in_recursion_semaphore) {
87 $current_tagged_tag_name = tag_get_name($record_id);
88 }
8479c2e0 89
90 $tags_ids = tag_get_id($tags, TAG_RETURN_ARRAY); // force an array, even if we only have one tag.
91 $cleaned_tags = tag_normalize($tags);
92 //echo 'tags-in-tag_set'; var_dump($tags); var_dump($tags_ids); var_dump($cleaned_tags);
93
28f64040 94 $current_ids = tag_get_tags_ids($record_type, $record_id);
986dca60 95 //var_dump($current_ids);
8479c2e0 96
97 // for data coherence reasons, it's better to remove deleted tags
98 // before adding new data: ordering could be duplicated.
99 foreach($current_ids as $current_id) {
100 if (!in_array($current_id, $tags_ids)) {
28f64040 101 tag_delete_instance($record_type, $record_id, $current_id);
102 if ( $record_type == 'tag' && !$in_recursion_semaphore) {
986dca60 103 // if we are removing a tag-on-a-tag (manually related tag),
28f64040 104 // we need to remove the opposite relationship as well.
105 tag_delete_instance('tag', $current_id, $record_id);
106 }
8479c2e0 107 }
c933a060 108 }
3d436d8a 109
0f097239 110 if (empty($tags)) {
111 return true;
112 }
113
8479c2e0 114 foreach($tags as $ordering => $tag) {
115 $tag = trim($tag);
116 if (!$tag) {
db32b054 117 continue;
118 }
8479c2e0 119
120 $clean_tag = $cleaned_tags[$tag];
121 $tag_current_id = $tags_ids[$clean_tag];
986dca60 122
8479c2e0 123 if ( is_null($tag_current_id) ) {
124 // create new tags
125 //echo "call to add tag $tag\n";
126 $new_tag = tag_add($tag);
28f64040 127 $tag_current_id = $new_tag[$clean_tag];
128 }
129
b91de8a5 130 tag_assign($record_type, $record_id, $tag_current_id, $ordering);
28f64040 131
132 // if we are tagging a tag (adding a manually-assigned related tag), we
133 // need to create the opposite relationship as well.
134 if ( $record_type == 'tag' && !$in_recursion_semaphore) {
135 $in_recursion_semaphore = true;
136 tag_set_add('tag', $tag_current_id, $current_tagged_tag_name);
137 $in_recursion_semaphore = false;
db32b054 138 }
139 }
8479c2e0 140}
3d436d8a 141
8479c2e0 142/**
143 * Adds a tag to a record, without overwriting the current tags.
986dca60 144 *
145 * @param string $record_type the type of record to tag ('post' for blogs,
8479c2e0 146 * 'user' for users, etc.
147 * @param int $record_id the id of the record to tag
148 * @param string $tag the tag to add
149 * @return void
150 */
b91de8a5 151function tag_set_add($record_type, $record_id, $tag) {
8479c2e0 152
153 $new_tags = array();
b91de8a5 154 foreach( tag_get_tags($record_type, $record_id) as $current_tag ) {
8479c2e0 155 $new_tags[] = $current_tag->rawname;
156 }
157 $new_tags[] = $tag;
986dca60 158
b91de8a5 159 return tag_set($record_type, $record_id, $new_tags);
c933a060 160}
161
162/**
8479c2e0 163 * Removes a tag from a record, without overwriting other current tags.
986dca60 164 *
165 * @param string $record_type the type of record to tag ('post' for blogs,
8479c2e0 166 * 'user' for users, etc.
167 * @param int $record_id the id of the record to tag
168 * @param string $tag the tag to delete
169 * @return void
c933a060 170 */
8479c2e0 171function tag_set_delete($record_type, $record_id, $tag) {
70e9b59d 172
8479c2e0 173 $new_tags = array();
174 foreach( tag_get_tags($record_type, $record_id) as $current_tag ) {
175 if ($current_tag->name != $tag) { // Keep all tags but the one specified
176 $new_tags[] = $current_tag->name;
db32b054 177 }
c933a060 178 }
28f64040 179
8479c2e0 180 return tag_set($record_type, $record_id, $new_tags);
181}
182
183/**
184 * Set the type of a tag. At this time (version 1.9) the possible values
185 * are 'default' or 'official'. Official tags will be displayed separately "at
186 * tagging time" (while selecting the tags to apply to a record).
187 *
188 * @param string $tagid tagid to modify
189 * @param string $type either 'default' or 'official'
190 * @return true on success, false otherwise
191 */
192function tag_type_set($tagid, $type) {
f7ed2687 193 global $DB;
194
195 if ($tag = $DB->get_record('tag', array('id'=>$tagid), 'id')) {
196 $tag->tagtype = $type;
8479c2e0 197 $tag->timemodified = time();
f7ed2687 198 return $DB->update_record('tag', $tag);
8479c2e0 199 }
200 return false;
c933a060 201}
202
8479c2e0 203
986dca60 204/**
b50d2245 205 * Set the description of a tag
986dca60 206 *
b50d2245 207 * @param int $tagid the id of the tag
208 * @param string $description the description
209 * @param int $descriptionformat the moodle text format of the description
986dca60 210 * @return true on success, false otherwise
b50d2245 211 */
212function tag_description_set($tagid, $description, $descriptionformat) {
f7ed2687 213 global $DB;
214
215 if ($tag = $DB->get_record('tag', array('id'=>$tagid),'id')) {
216 $tag->description = $description;
217 $tag->descriptionformat = $descriptionformat;
b50d2245 218 $tag->timemodified = time();
f7ed2687 219 return $DB->update_record('tag', $tag);
b50d2245 220 }
221 return false;
222}
223
3d436d8a 224
6361e02a 225
db32b054 226
c933a060 227
c933a060 228
8479c2e0 229/// Functions for getting information about tags //////
2f4b82f4 230
231/**
8479c2e0 232 * Simple function to just return a single tag object when you know the name or something
2f4b82f4 233 *
234 * @param string $field which field do we use to identify the tag: id, name or rawname
235 * @param string $value the required value of the aforementioned field
236 * @param string $returnfields which fields do we want returned?
237 * @return tag object
238 *
239 **/
240function tag_get($field, $value, $returnfields='id, name, rawname') {
f7ed2687 241 global $DB;
242
8479c2e0 243 if ($field == 'name') {
f7ed2687 244 $value = moodle_strtolower($value); // To cope with input that might just be wrong case
8479c2e0 245 }
f7ed2687 246 return $DB->get_record('tag', array($field=>$value), $returnfields);
2f4b82f4 247}
248
249
c933a060 250/**
986dca60 251 * Get the array of db record of tags associated to a record (instances). Use
db32b054 252 * tag_get_tags_csv to get the same information in a comma-separated string.
c933a060 253 *
986dca60 254 * @param string $record_type the record type for which we want to get the tags
255 * @param int $record_id the record id for which we want to get the tags
db32b054 256 * @param string $type the tag type (either 'default' or 'official'). By default,
257 * all tags are returned.
38fb8190 258 * @param int $userid optional only required for course tagging
db32b054 259 * @return array the array of tags
c933a060 260 */
38fb8190 261function tag_get_tags($record_type, $record_id, $type=null, $userid=0) {
f7ed2687 262 global $CFG, $DB;
263
264 $params = array();
3d436d8a 265
db32b054 266 if ($type) {
cda19b7a 267 $sql_type = "AND tg.tagtype = :type";
f7ed2687 268 $params['type'] = $type;
269 } else {
cda19b7a 270 $sql_type = '';
db32b054 271 }
537aa65c 272
38fb8190 273 $u = null;
274 if ($userid) {
275 $u = "AND ti.tiuserid = :userid ";
276 $params['userid'] = $userid;
277 }
278
f7ed2687 279 $sql = "SELECT tg.id, tg.tagtype, tg.name, tg.rawname, tg.flag, ti.ordering
280 FROM {tag_instance} ti JOIN {tag} tg ON tg.id = ti.tagid
38fb8190 281 WHERE ti.itemtype = :recordtype AND ti.itemid = :recordid $u $sql_type
f7ed2687 282 ORDER BY ti.ordering ASC";
283 $params['recordtype'] = $record_type;
284 $params['recordid'] = $record_id;
285
73c32e86 286 // if the fields in this query are changed, you need to do the same changes in tag_get_correlated_tags
f7ed2687 287 return $DB->get_records_sql($sql, $params);
986dca60 288 // This version of the query, reversing the ON clause, "correctly" returns
289 // a row with NULL values for instances that are still in the DB even though
290 // the tag has been deleted. This shouldn't happen, but if it did, using
db32b054 291 // this query could help "clean it up". This causes bugs at this time.
f7ed2687 292 //$tags = $DB->get_records_sql("SELECT ti.tagid, tg.tagtype, tg.name, tg.rawname, tg.flag, ti.ordering ".
5183f0cc 293 // "FROM {tag_instance} ti LEFT JOIN {tag} tg ON ti.tagid = tg.id ".
537aa65c 294 // "WHERE ti.itemtype = '{$record_type}' AND ti.itemid = '{$record_id}' {$type} ".
2f9ba531 295 // "ORDER BY ti.ordering ASC");
db32b054 296}
297
298/**
299 * Get the array of tags display names, indexed by id.
986dca60 300 *
537aa65c 301 * @param string $record_type the record type for which we want to get the tags
302 * @param int $record_id the record id for which we want to get the tags
db32b054 303 * @param string $type the tag type (either 'default' or 'official'). By default,
304 * all tags are returned.
305 * @return array the array of tags (with the value returned by tag_display_name), indexed by id
306 */
537aa65c 307function tag_get_tags_array($record_type, $record_id, $type=null) {
db32b054 308 $tags = array();
537aa65c 309 foreach(tag_get_tags($record_type, $record_id, $type) as $tag) {
db32b054 310 $tags[$tag->id] = tag_display_name($tag);
4f81c51d 311 }
db32b054 312 return $tags;
c933a060 313}
314
315/**
db32b054 316 * Get a comma-separated string of tags associated to a record. Use tag_get_tags
317 * to get the same information in an array.
c933a060 318 *
537aa65c 319 * @param string $record_type the record type for which we want to get the tags
320 * @param int $record_id the record id for which we want to get the tags
db32b054 321 * @param int $html either TAG_RETURN_HTML or TAG_RETURN_TEXT, depending
322 * on the type of output desired
323 * @param string $type either 'official' or 'default', if null, all tags are
324 * returned
325 * @return string the comma-separated list of tags.
c933a060 326 */
537aa65c 327function tag_get_tags_csv($record_type, $record_id, $html=TAG_RETURN_HTML, $type=null) {
db32b054 328 global $CFG;
c933a060 329
330 $tags_names = array();
8479c2e0 331 foreach(tag_get_tags($record_type, $record_id, $type) as $tag) {
db32b054 332 if ($html == TAG_RETURN_TEXT) {
e7134583 333 $tags_names[] = tag_display_name($tag, TAG_RETURN_TEXT);
db32b054 334 } else { // TAG_RETURN_HTML
335 $tags_names[] = '<a href="'. $CFG->wwwroot .'/tag/index.php?tag='. rawurlencode($tag->name) .'">'. tag_display_name($tag) .'</a>';
336 }
c933a060 337 }
db32b054 338 return implode(', ', $tags_names);
c933a060 339}
340
4f81c51d 341/**
db32b054 342 * Get an array of tag ids associated to a record.
d4be9d6d 343 *
28f64040 344 * @param string $record_type the record type for which we want to get the tags
537aa65c 345 * @param int $record_id the record id for which we want to get the tags
db32b054 346 * @return array of tag ids, indexed and sorted by 'ordering'
4f81c51d 347 */
537aa65c 348function tag_get_tags_ids($record_type, $record_id) {
986dca60 349
db32b054 350 $tag_ids = array();
8479c2e0 351 foreach (tag_get_tags($record_type, $record_id) as $tag) {
28f64040 352 if ( array_key_exists($tag->ordering, $tag_ids) ) {
353 // until we can add a unique constraint, in table tag_instance,
354 // on (itemtype, itemid, ordering), this is needed to prevent a bug
355 // TODO : modify database in 2.0
356 $tag->ordering++;
357 }
db32b054 358 $tag_ids[$tag->ordering] = $tag->id;
359 }
360 ksort($tag_ids);
361 return $tag_ids;
362}
3d436d8a 363
986dca60 364/**
db32b054 365 * Returns the database ID of a set of tags.
986dca60 366 *
db32b054 367 * @param mixed $tags one tag, or array of tags, to look for.
986dca60 368 * @param bool $return_value specify the type of the returned value. Either
369 * TAG_RETURN_OBJECT, or TAG_RETURN_ARRAY (default). If TAG_RETURN_ARRAY
370 * is specified, an array will be returned even if only one tag was
dee71a16 371 * passed in $tags.
986dca60 372 * @return mixed tag-indexed array of ids (or objects, if second parameter is
373 * TAG_RETURN_OBJECT), or only an int, if only one tag is given *and* the
dee71a16 374 * second parameter is null. No value for a key means the tag wasn't found.
db32b054 375 */
376function tag_get_id($tags, $return_value=null) {
f7ed2687 377 global $CFG, $DB;
378
db32b054 379 static $tag_id_cache = array();
3d436d8a 380
db32b054 381 $return_an_int = false;
382 if (!is_array($tags)) {
383 if(is_null($return_value) || $return_value == TAG_RETURN_OBJECT) {
986dca60 384 $return_an_int = true;
db32b054 385 }
386 $tags = array($tags);
387 }
986dca60 388
db32b054 389 $result = array();
986dca60 390
db32b054 391 //TODO: test this and see if it helps performance without breaking anything
392 //foreach($tags as $key => $tag) {
393 // $clean_tag = moodle_strtolower($tag);
394 // if ( array_key_exists($clean_tag), $tag_id_cache) ) {
395 // $result[$clean_tag] = $tag_id_cache[$clean_tag];
396 // $tags[$key] = ''; // prevent further processing for this one.
397 // }
398 //}
399
400 $tags = array_values(tag_normalize($tags));
401 foreach($tags as $key => $tag) {
986dca60 402 $tags[$key] = moodle_strtolower($tag);
db32b054 403 $result[moodle_strtolower($tag)] = null; // key must exists : no value for a key means the tag wasn't found.
404 }
db32b054 405
f7ed2687 406 if (empty($tags)) {
407 return array();
408 }
409
410 list($tag_string, $params) = $DB->get_in_or_equal($tags);
411
cd5fdfd8
EL
412 $rs = $DB->get_recordset_sql("SELECT * FROM {tag} WHERE name $tag_string ORDER BY name", $params);
413 foreach ($rs as $record) {
414 if ($return_value == TAG_RETURN_OBJECT) {
415 $result[$record->name] = $record;
416 } else { // TAG_RETURN_ARRAY
417 $result[$record->name] = $record->id;
db32b054 418 }
4f81c51d 419 }
cd5fdfd8 420 $rs->close();
3d436d8a 421
db32b054 422 if ($return_an_int) {
423 return array_pop($result);
424 }
3d436d8a 425
db32b054 426 return $result;
c933a060 427}
428
c933a060 429
430/**
db32b054 431 * Returns tags related to a tag
d4be9d6d 432 *
db32b054 433 * Related tags of a tag come from two sources:
434 * - manually added related tags, which are tag_instance entries for that tag
435 * - correlated tags, which are a calculated
d4be9d6d 436 *
986dca60 437 * @param string $tag_name_or_id is a single **normalized** tag name or the id
537aa65c 438 * of a tag
986dca60 439 * @param int $type the function will return either manually
440 * (TAG_RELATED_MANUAL) related tags or correlated (TAG_RELATED_CORRELATED)
537aa65c 441 * tags. Default is TAG_RELATED_ALL, which returns everything.
986dca60 442 * @param int $limitnum return a subset comprising this many records (optional,
537aa65c 443 * default is 10)
db32b054 444 * @return array an array of tag objects
c933a060 445 */
537aa65c 446function tag_get_related_tags($tagid, $type=TAG_RELATED_ALL, $limitnum=10) {
c933a060 447
537aa65c 448 $related_tags = array();
449
450 if ( $type == TAG_RELATED_ALL || $type == TAG_RELATED_MANUAL) {
451 //gets the manually added related tags
452 $related_tags = tag_get_tags('tag', $tagid);
c933a060 453 }
454
537aa65c 455 if ( $type == TAG_RELATED_ALL || $type == TAG_RELATED_CORRELATED ) {
456 //gets the correlated tags
457 $automatic_related_tags = tag_get_correlated($tagid, $limitnum);
458 if (is_array($automatic_related_tags)) {
459 $related_tags = array_merge($related_tags, $automatic_related_tags);
460 }
db32b054 461 }
3d436d8a 462
db32b054 463 return array_slice(object_array_unique($related_tags), 0 , $limitnum);
c933a060 464}
465
986dca60 466/**
db32b054 467 * Get a comma-separated list of tags related to another tag.
d4be9d6d 468 *
db32b054 469 * @param array $related_tags the array returned by tag_get_related_tags
470 * @param int $html either TAG_RETURN_HTML (default) or TAG_RETURN_TEXT : return html links, or just text.
471 * @return string comma-separated list
c933a060 472 */
db32b054 473function tag_get_related_tags_csv($related_tags, $html=TAG_RETURN_HTML) {
474 global $CFG;
c933a060 475
db32b054 476 $tags_names = array();
477 foreach($related_tags as $tag) {
478 if ( $html == TAG_RETURN_TEXT) {
e7134583 479 $tags_names[] = tag_display_name($tag, TAG_RETURN_TEXT);
db32b054 480 } else {
481 // TAG_RETURN_HTML
9fccb889 482 $tags_names[] = '<a href="'. $CFG->wwwroot .'/tag/index.php?tag='. rawurlencode($tag->name) .'">'. tag_display_name($tag) .'</a>';
c933a060 483 }
c933a060 484 }
b50d2245 485
db32b054 486 return implode(', ', $tags_names);
c933a060 487}
488
3a597ace 489/**
db32b054 490 * Change the "value" of a tag, and update the associated 'name'.
3a597ace 491 *
db32b054 492 * @param int $tagid the id of the tag to modify
73c32e86 493 * @param string $newtag the new rawname
db32b054 494 * @return bool true on success, false otherwise
3a597ace 495 */
73c32e86 496function tag_rename($tagid, $newrawname) {
f7ed2687 497 global $DB;
3a597ace 498
73c32e86 499 if (! $newrawname_clean = array_shift(tag_normalize($newrawname, TAG_CASE_ORIGINAL)) ) {
db32b054 500 return false;
501 }
3a597ace 502
2f4b82f4 503 if (! $newname_clean = moodle_strtolower($newrawname_clean)) {
504 return false;
505 }
506
507 // Prevent the rename if a tag with that name already exists
508 if ($existing = tag_get('name', $newname_clean, 'id, name, rawname')) {
509 if ($existing->id != $tagid) { // Another tag already exists with this name
986dca60 510 return false;
2f4b82f4 511 }
db32b054 512 }
3a597ace 513
2f4b82f4 514 if ($tag = tag_get('id', $tagid, 'id, name, rawname')) {
986dca60 515 $tag->rawname = $newrawname_clean;
516 $tag->name = $newname_clean;
db32b054 517 $tag->timemodified = time();
f7ed2687 518 return $DB->update_record('tag', $tag);
db32b054 519 }
520 return false;
3a597ace 521}
522
8479c2e0 523
c933a060 524/**
8479c2e0 525 * Delete one or more tag, and all their instances if there are any left.
986dca60 526 *
8479c2e0 527 * @param mixed $tagids one tagid (int), or one array of tagids to delete
986dca60 528 * @return bool true on success, false otherwise
c933a060 529 */
8479c2e0 530function tag_delete($tagids) {
f7ed2687 531 global $DB;
3d436d8a 532
8479c2e0 533 if (!is_array($tagids)) {
534 $tagids = array($tagids);
db32b054 535 }
3d436d8a 536
8479c2e0 537 $success = true;
8bdc9cac 538 $context = get_context_instance(CONTEXT_SYSTEM);
8479c2e0 539 foreach( $tagids as $tagid ) {
540 if (is_null($tagid)) { // can happen if tag doesn't exists
db32b054 541 continue;
26d8649f 542 }
986dca60 543 // only delete the main entry if there were no problems deleting all the
544 // instances - that (and the fact we won't often delete lots of tags)
8618fd2a 545 // is the reason for not using $DB->delete_records_select()
f7ed2687 546 if ($DB->delete_records('tag_instance', array('tagid'=>$tagid)) ) {
547 $success &= (bool) $DB->delete_records('tag', array('id'=>$tagid));
8bdc9cac
SH
548 // Delete all files associated with this tag
549 $fs = get_file_storage();
64f93798 550 $files = $fs->get_area_files($context->id, 'tag', 'description', $tagid);
8bdc9cac
SH
551 foreach ($files as $file) {
552 $file->delete();
553 }
1acd661d 554 }
c933a060 555 }
8479c2e0 556
557 return $success;
db32b054 558}
c933a060 559
db32b054 560/**
8479c2e0 561 * Delete one instance of a tag. If the last instance was deleted, it will
a72529c7 562 * also delete the tag, unless its type is 'official'.
8479c2e0 563 *
28f64040 564 * @param string $record_type the type of the record for which to remove the instance
565 * @param int $record_id the id of the record for which to remove the instance
8479c2e0 566 * @param int $tagid the tagid that needs to be removed
567 * @return bool true on success, false otherwise
db32b054 568 */
28f64040 569function tag_delete_instance($record_type, $record_id, $tagid) {
f7ed2687 570 global $CFG, $DB;
571
572 if ($DB->delete_records('tag_instance', array('tagid'=>$tagid, 'itemtype'=>$record_type, 'itemid'=>$record_id))) {
a72529c7 573 if (!$DB->record_exists_sql("SELECT * ".
574 "FROM {tag} tg ".
575 "WHERE tg.id = ? AND ( tg.tagtype = 'official' OR ".
b91de8a5 576 "EXISTS (SELECT 1
577 FROM {tag_instance} ti
578 WHERE ti.tagid = ?) )",
579 array($tagid, $tagid))) {
8479c2e0 580 return tag_delete($tagid);
581 }
582 } else {
583 return false;
db32b054 584 }
4a0daed7 585
586 return true;
db32b054 587}
c933a060 588
8479c2e0 589
3627b0e3 590/**
8479c2e0 591 * Function that returns the name that should be displayed for a specific tag
592 *
593 * @param object $tag_object a line out of tag table, as returned by the adobd functions
e7134583 594 * @param int $html TAG_RETURN_HTML (default) will return htmlspecialchars encoded string, TAG_RETURN_TEXT will not encode.
8479c2e0 595 * @return string
3627b0e3 596 */
e7134583 597function tag_display_name($tagobject, $html=TAG_RETURN_HTML) {
3627b0e3 598
8479c2e0 599 global $CFG;
600
34b93e39 601 if (!isset($tagobject->name)) {
8479c2e0 602 return '';
603 }
604
605 if (empty($CFG->keeptagnamecase)) {
606 //this is the normalized tag name
607 $textlib = textlib_get_instance();
e7134583 608 $tagname = $textlib->strtotitle($tagobject->name);
8479c2e0 609 } else {
610 //original casing of the tag name
e7134583 611 $tagname = $tagobject->rawname;
3627b0e3 612 }
e7134583 613
34b93e39
PS
614 // clean up a bit just in case the rules change again
615 $tagname = clean_param($tagname, PARAM_TAG);
616
e7134583 617 if ($html == TAG_RETURN_TEXT) {
618 return $tagname;
619 } else { // TAG_RETURN_HTML
620 return htmlspecialchars($tagname);
b91de8a5 621 }
3627b0e3 622}
623
db32b054 624/**
8479c2e0 625 * Find all records tagged with a tag of a given type ('post', 'user', etc.)
db32b054 626 *
8479c2e0 627 * @param string $tag tag to look for
628 * @param string $type type to restrict search to. If null, every matching
629 * record will be returned
630 * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
631 * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
632 * @return array of matching objects, indexed by record id, from the table containing the type requested
db32b054 633 */
8479c2e0 634function tag_find_records($tag, $type, $limitfrom='', $limitnum='') {
f7ed2687 635 global $CFG, $DB;
8479c2e0 636
637 if (!$tag || !$type) {
638 return array();
db32b054 639 }
8479c2e0 640
641 $tagid = tag_get_id($tag);
642
f7ed2687 643 $query = "SELECT it.*
644 FROM {".$type."} it INNER JOIN {tag_instance} tt ON it.id = tt.itemid
645 WHERE tt.itemtype = ? AND tt.tagid = ?";
646 $params = array($type, $tagid);
986dca60 647
648 return $DB->get_records_sql($query, $params, $limitfrom, $limitnum);
c933a060 649}
650
8479c2e0 651
652
653
db32b054 654///////////////////////////////////////////////////////
655/////////////////// PRIVATE TAG API ///////////////////
c933a060 656
657/**
986dca60 658 * Adds one or more tag in the database. This function should not be called
db32b054 659 * directly : you should use tag_set.
d4be9d6d 660 *
db32b054 661 * @param mixed $tags one tag, or an array of tags, to be created
986dca60 662 * @param string $type type of tag to be created ("default" is the default
db32b054 663 * value and "official" is the only other supported value at this time). An
664 * official tag is kept even if there are no records tagged with it.
986dca60 665 * @return an array of tags ids, indexed by their lowercase normalized names.
db32b054 666 * Any boolean false in the array indicates an error while adding the tag.
c933a060 667 */
db32b054 668function tag_add($tags, $type="default") {
f7ed2687 669 global $USER, $DB;
c933a060 670
db32b054 671 if (!is_array($tags)) {
672 $tags = array($tags);
c933a060 673 }
3d436d8a 674
db32b054 675 $tag_object = new StdClass;
f7ed2687 676 $tag_object->tagtype = $type;
677 $tag_object->userid = $USER->id;
678 $tag_object->timemodified = time();
c933a060 679
db32b054 680 $clean_tags = tag_normalize($tags, TAG_CASE_ORIGINAL);
c933a060 681
db32b054 682 $tags_ids = array();
683 foreach($clean_tags as $tag) {
684 $tag = trim($tag);
685 if (!$tag) {
686 $tags_ids[$tag] = false;
687 } else {
986dca60 688 // note that the difference between rawname and name is only
689 // capitalization : the rawname is NOT the same at the rawtag.
690 $tag_object->rawname = $tag;
f7ed2687 691 $tag_name_lc = moodle_strtolower($tag);
692 $tag_object->name = $tag_name_lc;
db32b054 693 //var_dump($tag_object);
f7ed2687 694 $tags_ids[$tag_name_lc] = $DB->insert_record('tag', $tag_object);
db32b054 695 }
696 }
c933a060 697
db32b054 698 return $tags_ids;
c933a060 699}
700
701/**
db32b054 702 * Assigns a tag to a record: if the record already exists, the time and
703 * ordering will be updated.
986dca60 704 *
28f64040 705 * @param string $record_type the type of the record that will be tagged
706 * @param int $record_id the id of the record that will be tagged
986dca60 707 * @param string $tagid the tag id to set on the record.
db32b054 708 * @param int $ordering the order of the instance for this record
38fb8190 709 * @param int $userid optional only required for course tagging
db32b054 710 * @return bool true on success, false otherwise
c933a060 711 */
38fb8190 712function tag_assign($record_type, $record_id, $tagid, $ordering, $userid = 0) {
f7ed2687 713 global $DB;
c933a060 714
38fb8190 715 if ( $tag_instance_object = $DB->get_record('tag_instance', array('tagid'=>$tagid, 'itemtype'=>$record_type, 'itemid'=>$record_id, 'tiuserid'=>$userid), 'id')) {
f7ed2687 716 $tag_instance_object->ordering = $ordering;
db32b054 717 $tag_instance_object->timemodified = time();
f7ed2687 718 return $DB->update_record('tag_instance', $tag_instance_object);
986dca60 719 } else {
db32b054 720 $tag_instance_object = new StdClass;
f7ed2687 721 $tag_instance_object->tagid = $tagid;
722 $tag_instance_object->itemid = $record_id;
723 $tag_instance_object->itemtype = $record_type;
724 $tag_instance_object->ordering = $ordering;
db32b054 725 $tag_instance_object->timemodified = time();
38fb8190 726 $tag_instance_object->tiuserid = $userid;
f7ed2687 727 return $DB->insert_record('tag_instance', $tag_instance_object);
c933a060 728 }
c933a060 729}
730
731/**
db32b054 732 * Function that returns tags that start with some text, for use by the autocomplete feature
d4be9d6d 733 *
db32b054 734 * @param string $text string that the tag names will be matched against
c933a060 735 * @return mixed an array of objects, or false if no records were found or an error occured.
736 */
db32b054 737function tag_autocomplete($text) {
f7ed2687 738 global $DB;
739 return $DB->get_records_sql("SELECT tg.id, tg.name, tg.rawname
740 FROM {tag} tg
741 WHERE tg.name LIKE ?", array(moodle_strtolower($text)."%"));
c933a060 742}
743
986dca60 744/**
9545cdba 745 * Clean up the tag tables, making sure all tagged object still exists.
746 *
747 * This should normally not be necessary, but in case related tags are not deleted
748 * when the tagged record is removed, this should be done once in a while, perhaps on
986dca60 749 * an occasional cron run. On a site with lots of tags, this could become an expensive
9545cdba 750 * function to call: don't run at peak time.
751 */
752function tag_cleanup() {
f7ed2687 753 global $DB;
9545cdba 754
f7ed2687 755 $instances = $DB->get_recordset('tag_instance');
9545cdba 756
084426c5 757 // cleanup tag instances
f7ed2687 758 foreach ($instances as $instance) {
9545cdba 759 $delete = false;
986dca60 760
f7ed2687 761 if (!$DB->record_exists('tag', array('id'=>$instance->tagid))) {
9545cdba 762 // if the tag has been removed, instance should be deleted.
763 $delete = true;
764 } else {
765 switch ($instance->itemtype) {
766 case 'user': // users are marked as deleted, but not actually deleted
f7ed2687 767 if ($DB->record_exists('user', array('id'=>$instance->itemid, 'deleted'=>1))) {
9545cdba 768 $delete = true;
769 }
770 break;
771 default: // anything else, if the instance is not there, delete.
f7ed2687 772 if (!$DB->record_exists($instance->itemtype, array('id'=>$instance->itemid))) {
9545cdba 773 $delete = true;
774 }
775 break;
776 }
777 }
778 if ($delete) {
779 tag_delete_instance($instance->itemtype, $instance->itemid, $instance->tagid);
780 //debugging('deleting tag_instance #'. $instance->id .', linked to tag id #'. $instance->tagid, DEBUG_DEVELOPER);
781 }
782 }
f7ed2687 783 $instances->close();
9545cdba 784
785 // TODO: this will only clean tags of type 'default'. This is good as
786 // it won't delete 'official' tags, but the day we get more than two
787 // types, we need to fix this.
f7ed2687 788 $unused_tags = $DB->get_recordset_sql("SELECT tg.id
789 FROM {tag} tg
790 WHERE tg.tagtype = 'default'
791 AND NOT EXISTS (
792 SELECT 'x'
793 FROM {tag_instance} ti
794 WHERE ti.tagid = tg.id
795 )");
9545cdba 796
084426c5 797 // cleanup tags
f7ed2687 798 foreach ($unused_tags as $unused_tag) {
084426c5 799 tag_delete($unused_tag->id);
800 //debugging('deleting unused tag #'. $unused_tag->id, DEBUG_DEVELOPER);
9545cdba 801 }
f7ed2687 802 $unused_tags->close();
9545cdba 803}
804
c933a060 805/**
db32b054 806 * Calculates and stores the correlated tags of all tags.
807 * The correlations are stored in the 'tag_correlation' table.
808 *
809 * Two tags are correlated if they appear together a lot.
810 * Ex.: Users tagged with "computers" will probably also be tagged with "algorithms".
d4be9d6d 811 *
db32b054 812 * The rationale for the 'tag_correlation' table is performance.
813 * It works as a cache for a potentially heavy load query done at the 'tag_instance' table.
814 * So, the 'tag_correlation' table stores redundant information derived from the 'tag_instance' table.
d4be9d6d 815 *
db32b054 816 * @param number $min_correlation cutoff percentage (optional, default is 2)
c933a060 817 */
db32b054 818function tag_compute_correlations($min_correlation=2) {
f7ed2687 819 global $DB;
3d436d8a 820
986dca60 821 if (!$all_tags = $DB->get_records('tag')) {
423a71b6 822 return;
823 }
db32b054 824
c213773d 825 $tag_correlation_obj = new stdClass();
db32b054 826 foreach($all_tags as $tag) {
827
828 // query that counts how many times any tag appears together in items
829 // with the tag passed as argument ($tag_id)
b91de8a5 830 $query = "SELECT tb.tagid
f7ed2687 831 FROM {tag_instance} ta JOIN {tag_instance} tb ON ta.itemid = tb.itemid
832 WHERE ta.tagid = ? AND tb.tagid <> ?
833 GROUP BY tb.tagid
db3d1302 834 HAVING COUNT(*) > ?
eafa83ef 835 ORDER BY COUNT(*) DESC";
f7ed2687 836 $params = array($tag->id, $tag->id, $min_correlation);
db32b054 837
838 $correlated = array();
839
986dca60 840 // Correlated tags happen when they appear together in more occasions
db32b054 841 // than $min_correlation.
f7ed2687 842 if ($tag_correlations = $DB->get_records_sql($query, $params)) {
db32b054 843 foreach($tag_correlations as $correlation) {
844f9c15 844 // commented out - now done in query. kept here in case it breaks on some db
845 // if($correlation->nr >= $min_correlation){
db32b054 846 $correlated[] = $correlation->tagid;
844f9c15 847 // }
db32b054 848 }
849 }
c933a060 850
844f9c15 851 if (empty($correlated)) {
852 continue;
853 }
854
db32b054 855 $correlated = implode(',', $correlated);
856 //var_dump($correlated);
857
858 //saves correlation info in the caching table
aced917b 859 if ($tag_correlation_obj = $DB->get_record('tag_correlation', array('tagid'=>$tag->id), 'id')) {
db32b054 860 $tag_correlation_obj->correlatedtags = $correlated;
f7ed2687 861 $DB->update_record('tag_correlation', $tag_correlation_obj);
db32b054 862 } else {
aced917b 863 $tag_correlation_obj = new stdClass();
db32b054 864 $tag_correlation_obj->tagid = $tag->id;
865 $tag_correlation_obj->correlatedtags = $correlated;
f7ed2687 866 $DB->insert_record('tag_correlation', $tag_correlation_obj);
db32b054 867 }
3d436d8a 868 }
db32b054 869}
870
871/**
872 * Tasks that should be performed at cron time
873 */
874function tag_cron() {
875 tag_compute_correlations();
0f5e5f5c 876 tag_cleanup();
db32b054 877}
878
0f039283 879/**
880 * Search for tags with names that match some text
881 *
882 * @param string $text escaped string that the tag names will be matched against
883 * @param boolean $ordered If true, tags are ordered by their popularity. If false, no ordering.
884 * @param int $limitfrom return a subset of records, starting at this point (optional, required if $limitnum is set).
885 * @param int $limitnum return a subset comprising this many records (optional, required if $limitfrom is set).
886 * @return mixed an array of objects, or false if no records were found or an error occured.
887 */
888function tag_find_tags($text, $ordered=true, $limitfrom='', $limitnum='') {
f7ed2687 889 global $DB;
0f039283 890
891 $text = array_shift(tag_normalize($text, TAG_CASE_LOWER));
892
893 if ($ordered) {
f7ed2687 894 $query = "SELECT tg.id, tg.name, tg.rawname, COUNT(ti.id) AS count
895 FROM {tag} tg LEFT JOIN {tag_instance} ti ON tg.id = ti.tagid
896 WHERE tg.name LIKE ?
897 GROUP BY tg.id, tg.name, tg.rawname
898 ORDER BY count DESC";
0f039283 899 } else {
f7ed2687 900 $query = "SELECT tg.id, tg.name, tg.rawname
901 FROM {tag} tg
902 WHERE tg.name LIKE ?";
0f039283 903 }
f7ed2687 904 $params = array("%{$text}%");
905 return $DB->get_records_sql($query, $params, $limitfrom , $limitnum);
0f039283 906}
907
986dca60 908/**
db32b054 909 * Get the name of a tag
986dca60 910 *
db32b054 911 * @param mixed $tagids the id of the tag, or an array of ids
912 * @return mixed string name of one tag, or id-indexed array of strings
913 */
914function tag_get_name($tagids) {
f7ed2687 915 global $DB;
3d436d8a 916
f7ed2687 917 if (!is_array($tagids)) {
918 if ($tag = $DB->get_record('tag', array('id'=>$tagids))) {
919 return $tag->name;
920 }
921 return false;
db32b054 922 }
c933a060 923
db32b054 924 $tag_names = array();
986dca60 925 foreach($DB->get_records_list('tag', 'id', $tagids) as $tag) {
db32b054 926 $tag_names[$tag->id] = $tag->name;
927 }
c933a060 928
db32b054 929 return $tag_names;
c933a060 930}
931
932/**
db32b054 933 * Returns the correlated tags of a tag, retrieved from the tag_correlation
986dca60 934 * table. Make sure cron runs, otherwise the table will be empty and this
db32b054 935 * function won't return anything.
c933a060 936 *
db32b054 937 * @param int $tag_id is a single tag id
938 * @return array an array of tag objects, empty if no correlated tags are found
c933a060 939 */
db32b054 940function tag_get_correlated($tag_id, $limitnum=null) {
f7ed2687 941 global $DB;
3d436d8a 942
f7ed2687 943 $tag_correlation = $DB->get_record('tag_correlation', array('tagid'=>$tag_id));
c933a060 944
db32b054 945 if (!$tag_correlation || empty($tag_correlation->correlatedtags)) {
946 return array();
c933a060 947 }
986dca60 948
73c32e86 949 // this is (and has to) return the same fields as the query in tag_get_tags
725c9404 950 if ( !$result = $DB->get_records_sql("SELECT DISTINCT tg.id, tg.tagtype, tg.name, tg.rawname, tg.flag, ti.ordering
f7ed2687 951 FROM {tag} tg INNER JOIN {tag_instance} ti ON tg.id = ti.tagid
952 WHERE tg.id IN ({$tag_correlation->correlatedtags})") ) {
db32b054 953 return array();
c933a060 954 }
986dca60 955
db32b054 956 return $result;
c933a060 957}
958
c933a060 959/**
db32b054 960 * Function that normalizes a list of tag names.
c933a060 961 *
db32b054 962 * @param mixed $tags array of tags, or a single tag.
986dca60 963 * @param int $case case to use for returned value (default: lower case).
0f039283 964 * Either TAG_CASE_LOWER (default) or TAG_CASE_ORIGINAL
986dca60 965 * @return array of lowercased normalized tags, indexed by the normalized tag,
0f039283 966 * in the same order as the original array. (Eg: 'Banana' => 'banana').
c933a060 967 */
db32b054 968function tag_normalize($rawtags, $case = TAG_CASE_LOWER) {
969
0f039283 970 // cache normalized tags, to prevent costly repeated calls to clean_param
db32b054 971 static $cleaned_tags_lc = array(); // lower case - use for comparison
972 static $cleaned_tags_mc = array(); // mixed case - use for saving to database
c933a060 973
db32b054 974 if ( !is_array($rawtags) ) {
975 $rawtags = array($rawtags);
976 }
c933a060 977
db32b054 978 $result = array();
979 foreach($rawtags as $rawtag) {
980 $rawtag = trim($rawtag);
981 if (!$rawtag) {
982 continue;
983 }
984 if ( !array_key_exists($rawtag, $cleaned_tags_lc) ) {
985 $cleaned_tags_lc[$rawtag] = moodle_strtolower( clean_param($rawtag, PARAM_TAG) );
986 $cleaned_tags_mc[$rawtag] = clean_param($rawtag, PARAM_TAG);
987 }
986dca60 988 if ( $case == TAG_CASE_LOWER ) {
db32b054 989 $result[$rawtag] = $cleaned_tags_lc[$rawtag];
990 } else { // TAG_CASE_ORIGINAL
991 $result[$rawtag] = $cleaned_tags_mc[$rawtag];
992 }
993 }
986dca60 994
db32b054 995 return $result;
c933a060 996}
997
998/**
0f039283 999 * Count how many records are tagged with a specific tag,
c933a060 1000 *
0f039283 1001 * @param string $record record to look for ('post', 'user', etc.)
1002 * @param int $tag is a single tag id
1003 * @return int number of mathing tags.
c933a060 1004 */
0f039283 1005function tag_record_count($record_type, $tagid) {
f7ed2687 1006 global $DB;
1007 return $DB->count_records('tag_instance', array('itemtype'=>$record_type, 'tagid'=>$tagid));
0f039283 1008}
c933a060 1009
0f039283 1010/**
986dca60 1011 * Determine if a record is tagged with a specific tag
0f039283 1012 *
1013 * @param string $record_type the record type to look for
1014 * @param int $record_id the record id to look for
1015 * @param string $tag a tag name
1016 * @return bool true if it is tagged, false otherwise
1017 */
1018function tag_record_tagged_with($record_type, $record_id, $tag) {
f7ed2687 1019 global $DB;
0f039283 1020 if ($tagid = tag_get_id($tag)) {
f7ed2687 1021 return $DB->count_records('tag_instance', array('itemtype'=>$record_type, 'itemid'=>$record_id, 'tagid'=>$tagid));
c933a060 1022 } else {
0f039283 1023 return 0; // tag doesn't exist
c933a060 1024 }
c933a060 1025}
1026
1027/**
db32b054 1028 * Flag a tag as inapropriate
986dca60 1029 *
db32b054 1030 * @param mixed $tagids one (int) tagid, or an array of tagids
1031 * @return void
c933a060 1032 */
db32b054 1033function tag_set_flag($tagids) {
f7ed2687 1034 global $DB;
1035
1036 $tagids = (array)$tagids;
db32b054 1037 foreach ($tagids as $tagid) {
f7ed2687 1038 $tag = $DB->get_record('tag', array('id'=>$tagid), 'id, flag');
c933a060 1039 $tag->flag++;
1040 $tag->timemodified = time();
f7ed2687 1041 $DB->update_record('tag', $tag);
c933a060 1042 }
1043}
1044
986dca60 1045/**
db32b054 1046 * Remove the inapropriate flag on a tag
986dca60 1047 *
db32b054 1048 * @param mixed $tagids one (int) tagid, or an array of tagids
1049 * @return bool true if function succeeds, false otherwise
c933a060 1050 */
db32b054 1051function tag_unset_flag($tagids) {
f7ed2687 1052 global $DB;
d4be9d6d 1053
db32b054 1054 if ( is_array($tagids) ) {
1055 $tagids = implode(',', $tagids);
ab86d9c7 1056 }
db32b054 1057 $timemodified = time();
cef53045 1058 return $DB->execute("UPDATE {tag} SET flag = 0, timemodified = ? WHERE id IN ($tagids)", array($timemodified));
c933a060 1059}