weekly release 2.9dev
[moodle.git] / tag / lib.php
CommitLineData
6bfe7aac 1<?php
000ebd5c
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2// This file is part of Moodle - http://moodle.org/
3//
4// Moodle is free software: you can redistribute it and/or modify
5// it under the terms of the GNU General Public License as published by
6// the Free Software Foundation, either version 3 of the License, or
7// (at your option) any later version.
8//
9// Moodle is distributed in the hope that it will be useful,
10// but WITHOUT ANY WARRANTY; without even the implied warranty of
11// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12// GNU General Public License for more details.
13//
14// You should have received a copy of the GNU General Public License
15// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
16
bcdcee90 17
c933a060 18/**
4a0daed7 19 * Moodle tag library
db32b054 20 *
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21 * Tag strings : you can use any character in tags, except the comma (which is the separator) and
22 * the '\' (backslash). Note that many spaces (or other blank characters) will get "compressed"
23 * into one. A tag string is always a rawurlencode'd string. This is the same behavior as
24 * http://del.icio.us.
d4be9d6d 25 *
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26 * A "record" is a php array (note that an object will work too) that contains the following
27 * variables :
28 * - type: The database table containing the record that we are tagging (eg: for a blog, this is
29 * the table named 'post', and for a user it is the table name 'user')
30 * - id: The id of the record
c933a060 31 *
986dca60 32 * BASIC INSTRUCTIONS :
33 * - to "tag a blog post" (for example):
cc033d48 34 * tag_set('post', $blog_post->id, $array_of_tags, 'core', $thecontext);
d4be9d6d 35 *
db32b054 36 * - to "remove all the tags on a blog post":
cc033d48 37 * tag_set('post', $blog_post->id, array(), 'core', $thecontext);
4a0daed7 38 *
39 * Tag set will create tags that need to be created.
d4be9d6d 40 *
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41 * @package core_tag
42 * @category tag
43 * @todo MDL-31090 turn this into a full-fledged categorization system. This could start by
44 * modifying (removing, probably) the 'tag type' to use another table describing the
45 * relationship between tags (parents, sibling, etc.), which could then be merged with
46 * the 'course categorization' system.
47 * @see http://www.php.net/manual/en/function.urlencode.php
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48 * @copyright 2007 Luiz Cruz <luiz.laydner@gmail.com>
49 * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
c933a060 50 */
51
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52/**
53 * Used to require that the return value from a function is an array.
54 * @see tag_set()
55 */
db32b054 56define('TAG_RETURN_ARRAY', 0);
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57/**
58 * Used to require that the return value from a function is an object.
59 * @see tag_set()
60 */
db32b054 61define('TAG_RETURN_OBJECT', 1);
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62/**
63 * Use to specify that HTML free text is expected to be returned from a function.
64 * @see tag_display_name()
65 */
db32b054 66define('TAG_RETURN_TEXT', 2);
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67/**
68 * Use to specify that encoded HTML is expected to be returned from a function.
69 * @see tag_display_name()
70 */
db32b054 71define('TAG_RETURN_HTML', 3);
c933a060 72
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73/**
74 * Used to specify that we wish a lowercased string to be returned
75 * @see tag_normal()
76 */
db32b054 77define('TAG_CASE_LOWER', 0);
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78/**
79 * Used to specify that we do not wish the case of the returned string to change
80 * @see tag_normal()
81 */
db32b054 82define('TAG_CASE_ORIGINAL', 1);
d4be9d6d 83
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84/**
85 * Used to specify that we want all related tags returned, no matter how they are related.
86 * @see tag_get_related_tags()
87 */
537aa65c 88define('TAG_RELATED_ALL', 0);
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89/**
90 * Used to specify that we only want back tags that were manually related.
91 * @see tag_get_related_tags()
92 */
537aa65c 93define('TAG_RELATED_MANUAL', 1);
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94/**
95 * Used to specify that we only want back tags where the relationship was automatically correlated.
96 * @see tag_get_related_tags()
97 */
537aa65c 98define('TAG_RELATED_CORRELATED', 2);
99
db32b054 100///////////////////////////////////////////////////////
101/////////////////// PUBLIC TAG API ////////////////////
c933a060 102
8479c2e0 103/// Functions for settings tags //////////////////////
104
c933a060 105/**
8479c2e0 106 * Set the tags assigned to a record. This overwrites the current tags.
986dca60 107 *
bcdcee90 108 * This function is meant to be fed the string coming up from the user interface, which contains all tags assigned to a record.
8479c2e0 109 *
cc033d48 110 * @package core_tag
bcdcee90 111 * @category tag
cc033d48
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112 * @access public
113 * @param string $record_type the type of record to tag ('post' for blogs, 'user' for users, 'tag' for tags, etc.)
114 * @param int $record_id the id of the record to tag
115 * @param array $tags the array of tags to set on the record. If given an empty array, all tags will be removed.
116 * @param string|null $component the component that was tagged
117 * @param int|null $contextid the context id of where this tag was assigned
118 * @return bool|null
c933a060 119 */
cc033d48 120function tag_set($record_type, $record_id, $tags, $component = null, $contextid = null) {
3d436d8a 121
28f64040 122 static $in_recursion_semaphore = false; // this is to prevent loops when tagging a tag
cc033d48 123
28f64040 124 if ( $record_type == 'tag' && !$in_recursion_semaphore) {
125 $current_tagged_tag_name = tag_get_name($record_id);
126 }
8479c2e0 127
128 $tags_ids = tag_get_id($tags, TAG_RETURN_ARRAY); // force an array, even if we only have one tag.
129 $cleaned_tags = tag_normalize($tags);
130 //echo 'tags-in-tag_set'; var_dump($tags); var_dump($tags_ids); var_dump($cleaned_tags);
131
28f64040 132 $current_ids = tag_get_tags_ids($record_type, $record_id);
986dca60 133 //var_dump($current_ids);
8479c2e0 134
135 // for data coherence reasons, it's better to remove deleted tags
136 // before adding new data: ordering could be duplicated.
137 foreach($current_ids as $current_id) {
138 if (!in_array($current_id, $tags_ids)) {
28f64040 139 tag_delete_instance($record_type, $record_id, $current_id);
140 if ( $record_type == 'tag' && !$in_recursion_semaphore) {
986dca60 141 // if we are removing a tag-on-a-tag (manually related tag),
28f64040 142 // we need to remove the opposite relationship as well.
143 tag_delete_instance('tag', $current_id, $record_id);
144 }
8479c2e0 145 }
c933a060 146 }
3d436d8a 147
0f097239 148 if (empty($tags)) {
149 return true;
150 }
151
8479c2e0 152 foreach($tags as $ordering => $tag) {
153 $tag = trim($tag);
154 if (!$tag) {
db32b054 155 continue;
156 }
8479c2e0 157
158 $clean_tag = $cleaned_tags[$tag];
159 $tag_current_id = $tags_ids[$clean_tag];
986dca60 160
8479c2e0 161 if ( is_null($tag_current_id) ) {
162 // create new tags
163 //echo "call to add tag $tag\n";
164 $new_tag = tag_add($tag);
28f64040 165 $tag_current_id = $new_tag[$clean_tag];
166 }
167
cc033d48 168 tag_assign($record_type, $record_id, $tag_current_id, $ordering, 0, $component, $contextid);
28f64040 169
170 // if we are tagging a tag (adding a manually-assigned related tag), we
171 // need to create the opposite relationship as well.
172 if ( $record_type == 'tag' && !$in_recursion_semaphore) {
173 $in_recursion_semaphore = true;
cc033d48 174 tag_set_add('tag', $tag_current_id, $current_tagged_tag_name, $component, $contextid);
28f64040 175 $in_recursion_semaphore = false;
db32b054 176 }
177 }
8479c2e0 178}
3d436d8a 179
8479c2e0 180/**
181 * Adds a tag to a record, without overwriting the current tags.
986dca60 182 *
cc033d48 183 * @package core_tag
bcdcee90 184 * @category tag
cc033d48
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185 * @access public
186 * @param string $record_type the type of record to tag ('post' for blogs, 'user' for users, etc.)
187 * @param int $record_id the id of the record to tag
188 * @param string $tag the tag to add
189 * @param string|null $component the component that was tagged
190 * @param int|null $contextid the context id of where this tag was assigned
191 * @return bool|null
8479c2e0 192 */
cc033d48 193function tag_set_add($record_type, $record_id, $tag, $component = null, $contextid = null) {
8479c2e0 194
195 $new_tags = array();
b91de8a5 196 foreach( tag_get_tags($record_type, $record_id) as $current_tag ) {
8479c2e0 197 $new_tags[] = $current_tag->rawname;
198 }
199 $new_tags[] = $tag;
986dca60 200
cc033d48 201 return tag_set($record_type, $record_id, $new_tags, $component, $contextid);
c933a060 202}
203
204/**
8479c2e0 205 * Removes a tag from a record, without overwriting other current tags.
986dca60 206 *
cc033d48 207 * @package core_tag
bcdcee90 208 * @category tag
cc033d48
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209 * @access public
210 * @param string $record_type the type of record to tag ('post' for blogs, 'user' for users, etc.)
211 * @param int $record_id the id of the record to tag
212 * @param string $tag the tag to delete
213 * @param string|null $component the component that was tagged
214 * @param int|null $contextid the context id of where this tag was assigned
215 * @return bool|null
c933a060 216 */
cc033d48 217function tag_set_delete($record_type, $record_id, $tag, $component = null, $contextid = null) {
70e9b59d 218
8479c2e0 219 $new_tags = array();
220 foreach( tag_get_tags($record_type, $record_id) as $current_tag ) {
221 if ($current_tag->name != $tag) { // Keep all tags but the one specified
222 $new_tags[] = $current_tag->name;
db32b054 223 }
c933a060 224 }
28f64040 225
cc033d48 226 return tag_set($record_type, $record_id, $new_tags, $component, $contextid);
8479c2e0 227}
228
229/**
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230 * Set the type of a tag. At this time (version 2.2) the possible values are 'default' or 'official'. Official tags will be
231 * displayed separately "at tagging time" (while selecting the tags to apply to a record).
8479c2e0 232 *
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233 * @package core_tag
234 * @category tag
235 * @access public
236 * @param string $tagid tagid to modify
237 * @param string $type either 'default' or 'official'
238 * @return bool true on success, false otherwise
8479c2e0 239 */
240function tag_type_set($tagid, $type) {
f7ed2687 241 global $DB;
242
09fce434 243 if ($tag = $DB->get_record('tag', array('id' => $tagid), 'id, userid, name, rawname')) {
f7ed2687 244 $tag->tagtype = $type;
8479c2e0 245 $tag->timemodified = time();
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246 $DB->update_record('tag', $tag);
247
248 $event = \core\event\tag_updated::create(array(
249 'objectid' => $tag->id,
250 'relateduserid' => $tag->userid,
251 'context' => context_system::instance(),
252 'other' => array(
253 'name' => $tag->name,
254 'rawname' => $tag->rawname
255 )
256 ));
257 $event->trigger();
258
259 return true;
8479c2e0 260 }
261 return false;
c933a060 262}
263
986dca60 264/**
b50d2245 265 * Set the description of a tag
986dca60 266 *
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267 * @package core_tag
268 * @category tag
269 * @access public
270 * @param int $tagid the id of the tag
271 * @param string $description the tag's description string to be set
272 * @param int $descriptionformat the moodle text format of the description
273 * {@link http://docs.moodle.org/dev/Text_formats_2.0#Database_structure}
274 * @return bool true on success, false otherwise
b50d2245 275 */
276function tag_description_set($tagid, $description, $descriptionformat) {
f7ed2687 277 global $DB;
278
09fce434 279 if ($tag = $DB->get_record('tag', array('id' => $tagid), 'id, userid, name, rawname')) {
f7ed2687 280 $tag->description = $description;
281 $tag->descriptionformat = $descriptionformat;
b50d2245 282 $tag->timemodified = time();
09fce434
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283 $DB->update_record('tag', $tag);
284
285 $event = \core\event\tag_updated::create(array(
286 'objectid' => $tag->id,
287 'relateduserid' => $tag->userid,
288 'context' => context_system::instance(),
289 'other' => array(
290 'name' => $tag->name,
291 'rawname' => $tag->rawname
292 )
293 ));
294 $event->trigger();
295
296 return true;
b50d2245 297 }
09fce434 298
b50d2245 299 return false;
300}
301
3d436d8a 302
6361e02a 303
db32b054 304
c933a060 305
c933a060 306
8479c2e0 307/// Functions for getting information about tags //////
2f4b82f4 308
309/**
8479c2e0 310 * Simple function to just return a single tag object when you know the name or something
2f4b82f4 311 *
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312 * @package core_tag
313 * @category tag
314 * @access public
315 * @param string $field which field do we use to identify the tag: id, name or rawname
316 * @param string $value the required value of the aforementioned field
317 * @param string $returnfields which fields do we want returned. This is a comma seperated string containing any combination of
318 * 'id', 'name', 'rawname' or '*' to include all fields.
319 * @return mixed tag object
320 */
2f4b82f4 321function tag_get($field, $value, $returnfields='id, name, rawname') {
f7ed2687 322 global $DB;
323
8479c2e0 324 if ($field == 'name') {
2f1e464a 325 $value = core_text::strtolower($value); // To cope with input that might just be wrong case
8479c2e0 326 }
f7ed2687 327 return $DB->get_record('tag', array($field=>$value), $returnfields);
2f4b82f4 328}
329
330
c933a060 331/**
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332 * Get the array of db record of tags associated to a record (instances). Use {@see tag_get_tags_csv()} if you wish to get the same
333 * data in a comma-separated string, for instances such as needing to simply display a list of tags to the end user. This should
334 * really be called tag_get_tag_instances().
c933a060 335 *
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336 * @package core_tag
337 * @category tag
338 * @access public
986dca60 339 * @param string $record_type the record type for which we want to get the tags
340 * @param int $record_id the record id for which we want to get the tags
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341 * @param string $type the tag type (either 'default' or 'official'). By default, all tags are returned.
342 * @param int $userid (optional) only required for course tagging
db32b054 343 * @return array the array of tags
c933a060 344 */
38fb8190 345function tag_get_tags($record_type, $record_id, $type=null, $userid=0) {
f7ed2687 346 global $CFG, $DB;
347
348 $params = array();
3d436d8a 349
db32b054 350 if ($type) {
cda19b7a 351 $sql_type = "AND tg.tagtype = :type";
f7ed2687 352 $params['type'] = $type;
353 } else {
cda19b7a 354 $sql_type = '';
db32b054 355 }
537aa65c 356
38fb8190 357 $u = null;
358 if ($userid) {
359 $u = "AND ti.tiuserid = :userid ";
360 $params['userid'] = $userid;
361 }
362
f45d62e7 363 $sql = "SELECT ti.id AS taginstanceid, tg.id, tg.tagtype, tg.name, tg.rawname, tg.flag, ti.ordering
638cf615
AD
364 FROM {tag_instance} ti
365 JOIN {tag} tg ON tg.id = ti.tagid
38fb8190 366 WHERE ti.itemtype = :recordtype AND ti.itemid = :recordid $u $sql_type
f7ed2687 367 ORDER BY ti.ordering ASC";
368 $params['recordtype'] = $record_type;
369 $params['recordid'] = $record_id;
370
73c32e86 371 // if the fields in this query are changed, you need to do the same changes in tag_get_correlated_tags
f7ed2687 372 return $DB->get_records_sql($sql, $params);
986dca60 373 // This version of the query, reversing the ON clause, "correctly" returns
374 // a row with NULL values for instances that are still in the DB even though
375 // the tag has been deleted. This shouldn't happen, but if it did, using
db32b054 376 // this query could help "clean it up". This causes bugs at this time.
f7ed2687 377 //$tags = $DB->get_records_sql("SELECT ti.tagid, tg.tagtype, tg.name, tg.rawname, tg.flag, ti.ordering ".
5183f0cc 378 // "FROM {tag_instance} ti LEFT JOIN {tag} tg ON ti.tagid = tg.id ".
537aa65c 379 // "WHERE ti.itemtype = '{$record_type}' AND ti.itemid = '{$record_id}' {$type} ".
2f9ba531 380 // "ORDER BY ti.ordering ASC");
db32b054 381}
382
383/**
384 * Get the array of tags display names, indexed by id.
986dca60 385 *
bcdcee90
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386 * @package core_tag
387 * @category tag
388 * @access public
389 * @param string $record_type the record type for which we want to get the tags
390 * @param int $record_id the record id for which we want to get the tags
391 * @param string $type the tag type (either 'default' or 'official'). By default, all tags are returned.
392 * @return array the array of tags (with the value returned by tag_display_name), indexed by id
db32b054 393 */
537aa65c 394function tag_get_tags_array($record_type, $record_id, $type=null) {
db32b054 395 $tags = array();
537aa65c 396 foreach(tag_get_tags($record_type, $record_id, $type) as $tag) {
db32b054 397 $tags[$tag->id] = tag_display_name($tag);
4f81c51d 398 }
db32b054 399 return $tags;
c933a060 400}
401
402/**
bcdcee90 403 * Get a comma-separated string of tags associated to a record. Use {@see tag_get_tags()} to get the same information in an array.
c933a060 404 *
bcdcee90
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405 * @package core_tag
406 * @category tag
407 * @access public
408 * @param string $record_type the record type for which we want to get the tags
409 * @param int $record_id the record id for which we want to get the tags
410 * @param int $html either TAG_RETURN_HTML or TAG_RETURN_TEXT, depending on the type of output desired
411 * @param string $type either 'official' or 'default', if null, all tags are returned
412 * @return string the comma-separated list of tags.
c933a060 413 */
537aa65c 414function tag_get_tags_csv($record_type, $record_id, $html=TAG_RETURN_HTML, $type=null) {
db32b054 415 global $CFG;
c933a060 416
417 $tags_names = array();
8479c2e0 418 foreach(tag_get_tags($record_type, $record_id, $type) as $tag) {
db32b054 419 if ($html == TAG_RETURN_TEXT) {
e7134583 420 $tags_names[] = tag_display_name($tag, TAG_RETURN_TEXT);
db32b054 421 } else { // TAG_RETURN_HTML
422 $tags_names[] = '<a href="'. $CFG->wwwroot .'/tag/index.php?tag='. rawurlencode($tag->name) .'">'. tag_display_name($tag) .'</a>';
423 }
c933a060 424 }
db32b054 425 return implode(', ', $tags_names);
c933a060 426}
427
4f81c51d 428/**
db32b054 429 * Get an array of tag ids associated to a record.
d4be9d6d 430 *
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431 * @package core_tag
432 * @category tag
433 * @access public
434 * @todo MDL-31150 Update ordering property
435 * @param string $record_type the record type for which we want to get the tags
436 * @param int $record_id the record id for which we want to get the tags
437 * @return array tag ids, indexed and sorted by 'ordering'
4f81c51d 438 */
537aa65c 439function tag_get_tags_ids($record_type, $record_id) {
db32b054 440 $tag_ids = array();
8479c2e0 441 foreach (tag_get_tags($record_type, $record_id) as $tag) {
28f64040 442 if ( array_key_exists($tag->ordering, $tag_ids) ) {
443 // until we can add a unique constraint, in table tag_instance,
444 // on (itemtype, itemid, ordering), this is needed to prevent a bug
bcdcee90 445 // TODO MDL-31150 modify database in 2.0
28f64040 446 $tag->ordering++;
447 }
db32b054 448 $tag_ids[$tag->ordering] = $tag->id;
449 }
450 ksort($tag_ids);
451 return $tag_ids;
452}
3d436d8a 453
986dca60 454/**
db32b054 455 * Returns the database ID of a set of tags.
986dca60 456 *
bcdcee90
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457 * @package core_tag
458 * @category tag
459 * @access public
460 * @todo MDL-31152 Test the commented MDL-31152 todo in this function to see if it helps performance
461 * without breaking anything.
462 * @param mixed $tags one tag, or array of tags, to look for.
463 * @param bool $return_value specify the type of the returned value. Either TAG_RETURN_OBJECT, or TAG_RETURN_ARRAY (default).
464 * If TAG_RETURN_ARRAY is specified, an array will be returned even if only one tag was passed in $tags.
465 * @return mixed tag-indexed array of ids (or objects, if second parameter is TAG_RETURN_OBJECT), or only an int, if only one tag
466 * is given *and* the second parameter is null. No value for a key means the tag wasn't found.
db32b054 467 */
468function tag_get_id($tags, $return_value=null) {
f7ed2687 469 global $CFG, $DB;
470
db32b054 471 static $tag_id_cache = array();
3d436d8a 472
db32b054 473 $return_an_int = false;
474 if (!is_array($tags)) {
475 if(is_null($return_value) || $return_value == TAG_RETURN_OBJECT) {
986dca60 476 $return_an_int = true;
db32b054 477 }
478 $tags = array($tags);
479 }
986dca60 480
db32b054 481 $result = array();
986dca60 482
bcdcee90 483 //TODO MDL-31152 test this and see if it helps performance without breaking anything
db32b054 484 //foreach($tags as $key => $tag) {
2f1e464a 485 // $clean_tag = core_text::strtolower($tag);
db32b054 486 // if ( array_key_exists($clean_tag), $tag_id_cache) ) {
487 // $result[$clean_tag] = $tag_id_cache[$clean_tag];
488 // $tags[$key] = ''; // prevent further processing for this one.
489 // }
490 //}
491
492 $tags = array_values(tag_normalize($tags));
493 foreach($tags as $key => $tag) {
2f1e464a
PS
494 $tags[$key] = core_text::strtolower($tag);
495 $result[core_text::strtolower($tag)] = null; // key must exists : no value for a key means the tag wasn't found.
db32b054 496 }
db32b054 497
f7ed2687 498 if (empty($tags)) {
499 return array();
500 }
501
502 list($tag_string, $params) = $DB->get_in_or_equal($tags);
503
cd5fdfd8
EL
504 $rs = $DB->get_recordset_sql("SELECT * FROM {tag} WHERE name $tag_string ORDER BY name", $params);
505 foreach ($rs as $record) {
506 if ($return_value == TAG_RETURN_OBJECT) {
507 $result[$record->name] = $record;
508 } else { // TAG_RETURN_ARRAY
509 $result[$record->name] = $record->id;
db32b054 510 }
4f81c51d 511 }
cd5fdfd8 512 $rs->close();
3d436d8a 513
db32b054 514 if ($return_an_int) {
515 return array_pop($result);
516 }
3d436d8a 517
db32b054 518 return $result;
c933a060 519}
520
c933a060 521
522/**
db32b054 523 * Returns tags related to a tag
d4be9d6d 524 *
db32b054 525 * Related tags of a tag come from two sources:
526 * - manually added related tags, which are tag_instance entries for that tag
bcdcee90 527 * - correlated tags, which are calculated
d4be9d6d 528 *
bcdcee90
GGC
529 * @package core_tag
530 * @category tag
531 * @access public
532 * @param string $tagid is a single **normalized** tag name or the id of a tag
533 * @param int $type the function will return either manually (TAG_RELATED_MANUAL) related tags or correlated
534 * (TAG_RELATED_CORRELATED) tags. Default is TAG_RELATED_ALL, which returns everything.
535 * @param int $limitnum (optional) return a subset comprising this many records, the default is 10
536 * @return array an array of tag objects
c933a060 537 */
537aa65c 538function tag_get_related_tags($tagid, $type=TAG_RELATED_ALL, $limitnum=10) {
c933a060 539
537aa65c 540 $related_tags = array();
541
542 if ( $type == TAG_RELATED_ALL || $type == TAG_RELATED_MANUAL) {
543 //gets the manually added related tags
544 $related_tags = tag_get_tags('tag', $tagid);
c933a060 545 }
546
537aa65c 547 if ( $type == TAG_RELATED_ALL || $type == TAG_RELATED_CORRELATED ) {
548 //gets the correlated tags
549 $automatic_related_tags = tag_get_correlated($tagid, $limitnum);
550 if (is_array($automatic_related_tags)) {
551 $related_tags = array_merge($related_tags, $automatic_related_tags);
552 }
db32b054 553 }
3d436d8a 554
db32b054 555 return array_slice(object_array_unique($related_tags), 0 , $limitnum);
c933a060 556}
557
986dca60 558/**
db32b054 559 * Get a comma-separated list of tags related to another tag.
d4be9d6d 560 *
bcdcee90
GGC
561 * @package core_tag
562 * @category tag
563 * @access public
564 * @param array $related_tags the array returned by tag_get_related_tags
565 * @param int $html either TAG_RETURN_HTML (default) or TAG_RETURN_TEXT : return html links, or just text.
566 * @return string comma-separated list
c933a060 567 */
db32b054 568function tag_get_related_tags_csv($related_tags, $html=TAG_RETURN_HTML) {
569 global $CFG;
c933a060 570
db32b054 571 $tags_names = array();
572 foreach($related_tags as $tag) {
573 if ( $html == TAG_RETURN_TEXT) {
e7134583 574 $tags_names[] = tag_display_name($tag, TAG_RETURN_TEXT);
db32b054 575 } else {
576 // TAG_RETURN_HTML
9fccb889 577 $tags_names[] = '<a href="'. $CFG->wwwroot .'/tag/index.php?tag='. rawurlencode($tag->name) .'">'. tag_display_name($tag) .'</a>';
c933a060 578 }
c933a060 579 }
b50d2245 580
db32b054 581 return implode(', ', $tags_names);
c933a060 582}
583
3a597ace 584/**
db32b054 585 * Change the "value" of a tag, and update the associated 'name'.
3a597ace 586 *
bcdcee90
GGC
587 * @package core_tag
588 * @category tag
589 * @access public
590 * @param int $tagid the id of the tag to modify
591 * @param string $newrawname the new rawname
592 * @return bool true on success, false otherwise
3a597ace 593 */
73c32e86 594function tag_rename($tagid, $newrawname) {
09fce434 595 global $COURSE, $DB;
3a597ace 596
7c2cc9c8
PS
597 $norm = tag_normalize($newrawname, TAG_CASE_ORIGINAL);
598 if (! $newrawname_clean = array_shift($norm) ) {
db32b054 599 return false;
600 }
3a597ace 601
2f1e464a 602 if (! $newname_clean = core_text::strtolower($newrawname_clean)) {
2f4b82f4 603 return false;
604 }
605
606 // Prevent the rename if a tag with that name already exists
607 if ($existing = tag_get('name', $newname_clean, 'id, name, rawname')) {
608 if ($existing->id != $tagid) { // Another tag already exists with this name
986dca60 609 return false;
2f4b82f4 610 }
db32b054 611 }
3a597ace 612
09fce434
MN
613 if ($tag = tag_get('id', $tagid, 'id, userid, name, rawname')) {
614 // Store the name before we change it.
615 $oldname = $tag->name;
616
617 $tag->rawname = $newrawname_clean;
618 $tag->name = $newname_clean;
db32b054 619 $tag->timemodified = time();
09fce434
MN
620 $DB->update_record('tag', $tag);
621
622 $event = \core\event\tag_updated::create(array(
623 'objectid' => $tag->id,
624 'relateduserid' => $tag->userid,
625 'context' => context_system::instance(),
626 'other' => array(
627 'name' => $newname_clean,
628 'rawname' => $newrawname_clean
629 )
630 ));
631 $event->set_legacy_logdata(array($COURSE->id, 'tag', 'update', 'index.php?id='. $tag->id, $oldname . '->'. $tag->name));
632 $event->trigger();
633
634 return true;
db32b054 635 }
636 return false;
3a597ace 637}
638
8479c2e0 639
c933a060 640/**
8479c2e0 641 * Delete one or more tag, and all their instances if there are any left.
986dca60 642 *
bcdcee90
GGC
643 * @package core_tag
644 * @category tag
645 * @access public
646 * @param mixed $tagids one tagid (int), or one array of tagids to delete
647 * @return bool true on success, false otherwise
c933a060 648 */
8479c2e0 649function tag_delete($tagids) {
f7ed2687 650 global $DB;
3d436d8a 651
8479c2e0 652 if (!is_array($tagids)) {
653 $tagids = array($tagids);
db32b054 654 }
3d436d8a 655
db456ec1
MN
656 // Use the tagids to create a select statement to be used later.
657 list($tagsql, $tagparams) = $DB->get_in_or_equal($tagids);
658
d9994071 659 // Store the tags and tag instances we are going to delete.
db456ec1 660 $tags = $DB->get_records_select('tag', 'id ' . $tagsql, $tagparams);
d9994071 661 $taginstances = $DB->get_records_select('tag_instance', 'tagid ' . $tagsql, $tagparams);
db456ec1
MN
662
663 // Delete all the tag instances.
664 $select = 'WHERE tagid ' . $tagsql;
665 $sql = "DELETE FROM {tag_instance} $select";
666 $DB->execute($sql, $tagparams);
667
668 // Delete all the tag correlations.
669 $sql = "DELETE FROM {tag_correlation} $select";
670 $DB->execute($sql, $tagparams);
671
672 // Delete all the tags.
673 $select = 'WHERE id ' . $tagsql;
674 $sql = "DELETE FROM {tag} $select";
675 $DB->execute($sql, $tagparams);
676
d9994071
MN
677 // Fire an event that these items were untagged.
678 if ($taginstances) {
679 // Save the system context in case the 'contextid' column in the 'tag_instance' table is null.
680 $syscontextid = context_system::instance()->id;
f3d98189 681 // Loop through the tag instances and fire a 'tag_removed'' event.
d9994071
MN
682 foreach ($taginstances as $taginstance) {
683 // We can not fire an event with 'null' as the contextid.
684 if (is_null($taginstance->contextid)) {
685 $taginstance->contextid = $syscontextid;
686 }
687
f3d98189
MN
688 // Trigger tag removed event.
689 $event = \core\event\tag_removed::create(array(
d9994071
MN
690 'objectid' => $taginstance->id,
691 'contextid' => $taginstance->contextid,
692 'other' => array(
693 'tagid' => $taginstance->tagid,
694 'tagname' => $tags[$taginstance->tagid]->name,
695 'tagrawname' => $tags[$taginstance->tagid]->rawname,
696 'itemid' => $taginstance->itemid,
697 'itemtype' => $taginstance->itemtype
698 )
699 ));
700 $event->add_record_snapshot('tag_instance', $taginstance);
701 $event->trigger();
702 }
703 }
704
db456ec1
MN
705 // Fire an event that these tags were deleted.
706 if ($tags) {
707 $context = context_system::instance();
708 foreach ($tags as $tag) {
8bdc9cac
SH
709 // Delete all files associated with this tag
710 $fs = get_file_storage();
db456ec1 711 $files = $fs->get_area_files($context->id, 'tag', 'description', $tag->id);
8bdc9cac
SH
712 foreach ($files as $file) {
713 $file->delete();
714 }
db456ec1
MN
715
716 // Trigger an event for deleting this tag.
717 $event = \core\event\tag_deleted::create(array(
718 'objectid' => $tag->id,
719 'relateduserid' => $tag->userid,
720 'context' => $context,
721 'other' => array(
722 'name' => $tag->name,
723 'rawname' => $tag->rawname
724 )
725 ));
726 $event->add_record_snapshot('tag', $tag);
727 $event->trigger();
1acd661d 728 }
c933a060 729 }
8479c2e0 730
db456ec1 731 return true;
db32b054 732}
c933a060 733
d9994071
MN
734/**
735 * Deletes all the tag instances given a component and an optional contextid.
736 *
737 * @param string $component
738 * @param int $contextid if null, then we delete all tag instances for the $component
739 */
740function tag_delete_instances($component, $contextid = null) {
741 global $DB;
742
743 $sql = "SELECT ti.*, t.name, t.rawname
744 FROM {tag_instance} ti
745 JOIN {tag} t
746 ON ti.tagid = t.id ";
747 if (is_null($contextid)) {
748 $params = array('component' => $component);
749 $sql .= "WHERE ti.component = :component";
750 } else {
751 $params = array('component' => $component, 'contextid' => $contextid);
752 $sql .= "WHERE ti.component = :component
753 AND ti.contextid = :contextid";
754 }
755 if ($taginstances = $DB->get_records_sql($sql, $params)) {
756 // Now remove all the tag instances.
757 $DB->delete_records('tag_instance',$params);
758 // Save the system context in case the 'contextid' column in the 'tag_instance' table is null.
759 $syscontextid = context_system::instance()->id;
f3d98189 760 // Loop through the tag instances and fire an 'tag_removed' event.
d9994071
MN
761 foreach ($taginstances as $taginstance) {
762 // We can not fire an event with 'null' as the contextid.
763 if (is_null($taginstance->contextid)) {
764 $taginstance->contextid = $syscontextid;
765 }
766
f3d98189
MN
767 // Trigger tag removed event.
768 $event = \core\event\tag_removed::create(array(
d9994071
MN
769 'objectid' => $taginstance->id,
770 'contextid' => $taginstance->contextid,
771 'other' => array(
772 'tagid' => $taginstance->tagid,
773 'tagname' => $taginstance->name,
774 'tagrawname' => $taginstance->rawname,
775 'itemid' => $taginstance->itemid,
776 'itemtype' => $taginstance->itemtype
777 )
778 ));
779 $event->add_record_snapshot('tag_instance', $taginstance);
780 $event->trigger();
781 }
782 }
783}
784
db32b054 785/**
bcdcee90 786 * Delete one instance of a tag. If the last instance was deleted, it will also delete the tag, unless its type is 'official'.
8479c2e0 787 *
bcdcee90
GGC
788 * @package core_tag
789 * @category tag
790 * @access public
791 * @param string $record_type the type of the record for which to remove the instance
792 * @param int $record_id the id of the record for which to remove the instance
793 * @param int $tagid the tagid that needs to be removed
d9994071 794 * @param int $userid (optional) the userid
bcdcee90 795 * @return bool true on success, false otherwise
db32b054 796 */
d9994071
MN
797function tag_delete_instance($record_type, $record_id, $tagid, $userid = null) {
798 global $DB;
799
800 if (is_null($userid)) {
801 $taginstance = $DB->get_record('tag_instance', array('tagid' => $tagid, 'itemtype' => $record_type, 'itemid' => $record_id));
802 } else {
803 $taginstance = $DB->get_record('tag_instance', array('tagid' => $tagid, 'itemtype' => $record_type, 'itemid' => $record_id,
804 'tiuserid' => $userid));
805 }
806 if ($taginstance) {
807 // Get the tag.
808 $tag = $DB->get_record('tag', array('id' => $tagid));
809
810 $DB->delete_records('tag_instance', array('id' => $taginstance->id));
811
812 // We can not fire an event with 'null' as the contextid.
813 if (is_null($taginstance->contextid)) {
814 $taginstance->contextid = context_system::instance()->id;
815 }
816
f3d98189
MN
817 // Trigger tag removed event.
818 $event = \core\event\tag_removed::create(array(
d9994071
MN
819 'objectid' => $taginstance->id,
820 'contextid' => $taginstance->contextid,
821 'other' => array(
822 'tagid' => $tag->id,
823 'tagname' => $tag->name,
824 'tagrawname' => $tag->rawname,
825 'itemid' => $taginstance->itemid,
826 'itemtype' => $taginstance->itemtype
827 )
828 ));
829 $event->add_record_snapshot('tag_instance', $taginstance);
830 $event->trigger();
f7ed2687 831
d9994071
MN
832 // If there are no other instances of the tag then consider deleting the tag as well.
833 if (!$DB->record_exists('tag_instance', array('tagid' => $tagid))) {
834 // If the tag is a personal tag then delete it - don't delete official tags.
835 if ($tag->tagtype == 'default') {
836 tag_delete($tagid);
837 }
8479c2e0 838 }
839 } else {
840 return false;
db32b054 841 }
4a0daed7 842
843 return true;
db32b054 844}
c933a060 845
8479c2e0 846
3627b0e3 847/**
8479c2e0 848 * Function that returns the name that should be displayed for a specific tag
849 *
bcdcee90
GGC
850 * @package core_tag
851 * @category tag
852 * @access public
853 * @param object $tagobject a line out of tag table, as returned by the adobd functions
854 * @param int $html TAG_RETURN_HTML (default) will return htmlspecialchars encoded string, TAG_RETURN_TEXT will not encode.
855 * @return string
3627b0e3 856 */
e7134583 857function tag_display_name($tagobject, $html=TAG_RETURN_HTML) {
8479c2e0 858 global $CFG;
859
34b93e39 860 if (!isset($tagobject->name)) {
8479c2e0 861 return '';
862 }
863
864 if (empty($CFG->keeptagnamecase)) {
865 //this is the normalized tag name
2f1e464a 866 $tagname = core_text::strtotitle($tagobject->name);
8479c2e0 867 } else {
868 //original casing of the tag name
e7134583 869 $tagname = $tagobject->rawname;
3627b0e3 870 }
e7134583 871
34b93e39
PS
872 // clean up a bit just in case the rules change again
873 $tagname = clean_param($tagname, PARAM_TAG);
874
e7134583 875 if ($html == TAG_RETURN_TEXT) {
876 return $tagname;
877 } else { // TAG_RETURN_HTML
878 return htmlspecialchars($tagname);
b91de8a5 879 }
3627b0e3 880}
881
db32b054 882/**
8479c2e0 883 * Find all records tagged with a tag of a given type ('post', 'user', etc.)
db32b054 884 *
bcdcee90
GGC
885 * @package core_tag
886 * @category tag
887 * @access public
888 * @param string $tag tag to look for
889 * @param string $type type to restrict search to. If null, every matching record will be returned
890 * @param int $limitfrom (optional, required if $limitnum is set) return a subset of records, starting at this point.
891 * @param int $limitnum (optional, required if $limitfrom is set) return a subset comprising this many records.
892 * @return array of matching objects, indexed by record id, from the table containing the type requested
db32b054 893 */
8479c2e0 894function tag_find_records($tag, $type, $limitfrom='', $limitnum='') {
f7ed2687 895 global $CFG, $DB;
8479c2e0 896
897 if (!$tag || !$type) {
898 return array();
db32b054 899 }
8479c2e0 900
901 $tagid = tag_get_id($tag);
902
f7ed2687 903 $query = "SELECT it.*
904 FROM {".$type."} it INNER JOIN {tag_instance} tt ON it.id = tt.itemid
905 WHERE tt.itemtype = ? AND tt.tagid = ?";
906 $params = array($type, $tagid);
986dca60 907
908 return $DB->get_records_sql($query, $params, $limitfrom, $limitnum);
c933a060 909}
910
8479c2e0 911
912
913
db32b054 914///////////////////////////////////////////////////////
915/////////////////// PRIVATE TAG API ///////////////////
c933a060 916
917/**
bcdcee90
GGC
918 * Adds one or more tag in the database. This function should not be called directly : you should
919 * use tag_set.
d4be9d6d 920 *
bcdcee90
GGC
921 * @package core_tag
922 * @access private
923 * @param mixed $tags one tag, or an array of tags, to be created
924 * @param string $type type of tag to be created ("default" is the default value and "official" is the only other supported
925 * value at this time). An official tag is kept even if there are no records tagged with it.
926 * @return array $tags ids indexed by their lowercase normalized names. Any boolean false in the array indicates an error while
927 * adding the tag.
c933a060 928 */
db32b054 929function tag_add($tags, $type="default") {
f7ed2687 930 global $USER, $DB;
c933a060 931
db32b054 932 if (!is_array($tags)) {
933 $tags = array($tags);
c933a060 934 }
3d436d8a 935
db32b054 936 $tag_object = new StdClass;
f7ed2687 937 $tag_object->tagtype = $type;
938 $tag_object->userid = $USER->id;
939 $tag_object->timemodified = time();
c933a060 940
db32b054 941 $clean_tags = tag_normalize($tags, TAG_CASE_ORIGINAL);
c933a060 942
db32b054 943 $tags_ids = array();
944 foreach($clean_tags as $tag) {
945 $tag = trim($tag);
946 if (!$tag) {
947 $tags_ids[$tag] = false;
948 } else {
986dca60 949 // note that the difference between rawname and name is only
950 // capitalization : the rawname is NOT the same at the rawtag.
951 $tag_object->rawname = $tag;
2f1e464a 952 $tag_name_lc = core_text::strtolower($tag);
f7ed2687 953 $tag_object->name = $tag_name_lc;
db32b054 954 //var_dump($tag_object);
f7ed2687 955 $tags_ids[$tag_name_lc] = $DB->insert_record('tag', $tag_object);
bf2ae267
MN
956
957 $event = \core\event\tag_created::create(array(
958 'objectid' => $tags_ids[$tag_name_lc],
959 'relateduserid' => $tag_object->userid,
960 'context' => context_system::instance(),
961 'other' => array(
962 'name' => $tag_object->name,
963 'rawname' => $tag_object->rawname
964 )
965 ));
966 $event->trigger();
db32b054 967 }
968 }
c933a060 969
db32b054 970 return $tags_ids;
c933a060 971}
972
973/**
bcdcee90 974 * Assigns a tag to a record; if the record already exists, the time and ordering will be updated.
986dca60 975 *
bcdcee90 976 * @package core_tag
cc033d48
MN
977 * @access private
978 * @param string $record_type the type of the record that will be tagged
979 * @param int $record_id the id of the record that will be tagged
980 * @param string $tagid the tag id to set on the record.
981 * @param int $ordering the order of the instance for this record
982 * @param int $userid (optional) only required for course tagging
983 * @param string|null $component the component that was tagged
984 * @param int|null $contextid the context id of where this tag was assigned
985 * @return bool true on success, false otherwise
c933a060 986 */
cc033d48 987function tag_assign($record_type, $record_id, $tagid, $ordering, $userid = 0, $component = null, $contextid = null) {
f7ed2687 988 global $DB;
c933a060 989
cc033d48
MN
990 if ($component === null || $contextid === null) {
991 debugging('You should specify the component and contextid of the item being tagged in your call to tag_assign.',
992 DEBUG_DEVELOPER);
993 }
994
cfa2c6e1
MN
995 // Get the tag.
996 $tag = $DB->get_record('tag', array('id' => $tagid), 'name, rawname', MUST_EXIST);
997
38fb8190 998 if ( $tag_instance_object = $DB->get_record('tag_instance', array('tagid'=>$tagid, 'itemtype'=>$record_type, 'itemid'=>$record_id, 'tiuserid'=>$userid), 'id')) {
f7ed2687 999 $tag_instance_object->ordering = $ordering;
db32b054 1000 $tag_instance_object->timemodified = time();
cfa2c6e1
MN
1001
1002 $DB->update_record('tag_instance', $tag_instance_object);
986dca60 1003 } else {
db32b054 1004 $tag_instance_object = new StdClass;
f7ed2687 1005 $tag_instance_object->tagid = $tagid;
cc033d48 1006 $tag_instance_object->component = $component;
f7ed2687 1007 $tag_instance_object->itemid = $record_id;
1008 $tag_instance_object->itemtype = $record_type;
cc033d48 1009 $tag_instance_object->contextid = $contextid;
f7ed2687 1010 $tag_instance_object->ordering = $ordering;
cc033d48
MN
1011 $tag_instance_object->timecreated = time();
1012 $tag_instance_object->timemodified = $tag_instance_object->timecreated;
38fb8190 1013 $tag_instance_object->tiuserid = $userid;
cc033d48 1014
cfa2c6e1
MN
1015 $tag_instance_object->id = $DB->insert_record('tag_instance', $tag_instance_object);
1016 }
1017
1018 // We can not fire an event with 'null' as the contextid.
1019 if (is_null($contextid)) {
1020 $contextid = context_system::instance()->id;
c933a060 1021 }
cfa2c6e1 1022
f3d98189
MN
1023 // Trigger tag added event.
1024 $event = \core\event\tag_added::create(array(
cfa2c6e1
MN
1025 'objectid' => $tag_instance_object->id,
1026 'contextid' => $contextid,
1027 'other' => array(
1028 'tagid' => $tagid,
1029 'tagname' => $tag->name,
1030 'tagrawname' => $tag->rawname,
1031 'itemid' => $record_id,
1032 'itemtype' => $record_type
1033 )
1034 ));
1035 $event->trigger();
1036
1037 return true;
c933a060 1038}
1039
1040/**
db32b054 1041 * Function that returns tags that start with some text, for use by the autocomplete feature
d4be9d6d 1042 *
bcdcee90
GGC
1043 * @package core_tag
1044 * @access private
1045 * @param string $text string that the tag names will be matched against
1046 * @return mixed an array of objects, or false if no records were found or an error occured.
c933a060 1047 */
db32b054 1048function tag_autocomplete($text) {
f7ed2687 1049 global $DB;
1050 return $DB->get_records_sql("SELECT tg.id, tg.name, tg.rawname
1051 FROM {tag} tg
2f1e464a 1052 WHERE tg.name LIKE ?", array(core_text::strtolower($text)."%"));
c933a060 1053}
1054
986dca60 1055/**
9545cdba 1056 * Clean up the tag tables, making sure all tagged object still exists.
1057 *
bcdcee90
GGC
1058 * This should normally not be necessary, but in case related tags are not deleted when the tagged record is removed, this should be
1059 * done once in a while, perhaps on an occasional cron run. On a site with lots of tags, this could become an expensive function to
1060 * call: don't run at peak time.
1061 *
1062 * @package core_tag
1063 * @access private
1064 * @todo MDL-31212 Update tag cleanup sql so that it supports multiple types of tags
9545cdba 1065 */
1066function tag_cleanup() {
f7ed2687 1067 global $DB;
9545cdba 1068
f7ed2687 1069 $instances = $DB->get_recordset('tag_instance');
9545cdba 1070
084426c5 1071 // cleanup tag instances
f7ed2687 1072 foreach ($instances as $instance) {
9545cdba 1073 $delete = false;
986dca60 1074
f7ed2687 1075 if (!$DB->record_exists('tag', array('id'=>$instance->tagid))) {
9545cdba 1076 // if the tag has been removed, instance should be deleted.
1077 $delete = true;
1078 } else {
1079 switch ($instance->itemtype) {
1080 case 'user': // users are marked as deleted, but not actually deleted
f7ed2687 1081 if ($DB->record_exists('user', array('id'=>$instance->itemid, 'deleted'=>1))) {
9545cdba 1082 $delete = true;
1083 }
1084 break;
1085 default: // anything else, if the instance is not there, delete.
f7ed2687 1086 if (!$DB->record_exists($instance->itemtype, array('id'=>$instance->itemid))) {
9545cdba 1087 $delete = true;
1088 }
1089 break;
1090 }
1091 }
1092 if ($delete) {
1093 tag_delete_instance($instance->itemtype, $instance->itemid, $instance->tagid);
1094 //debugging('deleting tag_instance #'. $instance->id .', linked to tag id #'. $instance->tagid, DEBUG_DEVELOPER);
1095 }
1096 }
f7ed2687 1097 $instances->close();
9545cdba 1098
bcdcee90 1099 // TODO MDL-31212 this will only clean tags of type 'default'. This is good as
9545cdba 1100 // it won't delete 'official' tags, but the day we get more than two
1101 // types, we need to fix this.
f7ed2687 1102 $unused_tags = $DB->get_recordset_sql("SELECT tg.id
1103 FROM {tag} tg
1104 WHERE tg.tagtype = 'default'
1105 AND NOT EXISTS (
1106 SELECT 'x'
1107 FROM {tag_instance} ti
1108 WHERE ti.tagid = tg.id
1109 )");
9545cdba 1110
084426c5 1111 // cleanup tags
f7ed2687 1112 foreach ($unused_tags as $unused_tag) {
084426c5 1113 tag_delete($unused_tag->id);
1114 //debugging('deleting unused tag #'. $unused_tag->id, DEBUG_DEVELOPER);
9545cdba 1115 }
f7ed2687 1116 $unused_tags->close();
9545cdba 1117}
1118
c933a060 1119/**
bcdcee90 1120 * Calculates and stores the correlated tags of all tags. The correlations are stored in the 'tag_correlation' table.
db32b054 1121 *
bcdcee90 1122 * Two tags are correlated if they appear together a lot. Ex.: Users tagged with "computers" will probably also be tagged with "algorithms".
d4be9d6d 1123 *
bcdcee90
GGC
1124 * The rationale for the 'tag_correlation' table is performance. It works as a cache for a potentially heavy load query done at the
1125 * 'tag_instance' table. So, the 'tag_correlation' table stores redundant information derived from the 'tag_instance' table.
d4be9d6d 1126 *
bcdcee90
GGC
1127 * @package core_tag
1128 * @access private
1129 * @param int $mincorrelation Only tags with more than $mincorrelation correlations will be identified.
c933a060 1130 */
78defd5c 1131function tag_compute_correlations($mincorrelation = 2) {
f7ed2687 1132 global $DB;
3d436d8a 1133
78defd5c
SH
1134 // This mighty one line query fetches a row from the database for every
1135 // individual tag correlation. We then need to process the rows collecting
1136 // the correlations for each tag id.
1137 // The fields used by this query are as follows:
1138 // tagid : This is the tag id, there should be at least $mincorrelation
1139 // rows for each tag id.
1140 // correlation : This is the tag id that correlates to the above tagid field.
1141 // correlationid : This is the id of the row in the tag_correlation table that
1142 // relates to the tagid field and will be NULL if there are no
1143 // existing correlations
2650c547 1144 $sql = 'SELECT pairs.tagid, pairs.correlation, pairs.ocurrences, co.id AS correlationid
1c2cfff0
EL
1145 FROM (
1146 SELECT ta.tagid, tb.tagid AS correlation, COUNT(*) AS ocurrences
1147 FROM {tag_instance} ta
1148 JOIN {tag_instance} tb ON (ta.itemtype = tb.itemtype AND ta.itemid = tb.itemid AND ta.tagid <> tb.tagid)
1149 GROUP BY ta.tagid, tb.tagid
1150 HAVING COUNT(*) > :mincorrelation
1151 ) pairs
1152 LEFT JOIN {tag_correlation} co ON co.tagid = pairs.tagid
1153 ORDER BY pairs.tagid ASC, pairs.ocurrences DESC, pairs.correlation ASC';
78defd5c
SH
1154 $rs = $DB->get_recordset_sql($sql, array('mincorrelation' => $mincorrelation));
1155
1156 // Set up an empty tag correlation object
1157 $tagcorrelation = new stdClass;
1158 $tagcorrelation->id = null;
1159 $tagcorrelation->tagid = null;
1160 $tagcorrelation->correlatedtags = array();
1161
638cf615 1162 // We store each correlation id in this array so we can remove any correlations
2650c547
SH
1163 // that no longer exist.
1164 $correlations = array();
1165
78defd5c 1166 // Iterate each row of the result set and build them into tag correlations.
638cf615
AD
1167 // We add all of a tag's correlations to $tagcorrelation->correlatedtags[]
1168 // then save the $tagcorrelation object
78defd5c
SH
1169 foreach ($rs as $row) {
1170 if ($row->tagid != $tagcorrelation->tagid) {
638cf615 1171 // The tag id has changed so we have all of the correlations for this tag
2650c547
SH
1172 $tagcorrelationid = tag_process_computed_correlation($tagcorrelation);
1173 if ($tagcorrelationid) {
1174 $correlations[] = $tagcorrelationid;
1175 }
78defd5c
SH
1176 // Now we reset the tag correlation object so we can reuse it and set it
1177 // up for the current record.
1178 $tagcorrelation = new stdClass;
1179 $tagcorrelation->id = $row->correlationid;
1180 $tagcorrelation->tagid = $row->tagid;
1181 $tagcorrelation->correlatedtags = array();
db32b054 1182 }
638cf615 1183 //Save the correlation on the tag correlation object
78defd5c
SH
1184 $tagcorrelation->correlatedtags[] = $row->correlation;
1185 }
1186 // Update the current correlation after the last record.
2650c547
SH
1187 $tagcorrelationid = tag_process_computed_correlation($tagcorrelation);
1188 if ($tagcorrelationid) {
1189 $correlations[] = $tagcorrelationid;
1190 }
1191
c933a060 1192
78defd5c
SH
1193 // Close the recordset
1194 $rs->close();
2650c547
SH
1195
1196 // Remove any correlations that weren't just identified
638cf615
AD
1197 if (empty($correlations)) {
1198 //there are no tag correlations
1199 $DB->delete_records('tag_correlation');
1200 } else {
1201 list($sql, $params) = $DB->get_in_or_equal($correlations, SQL_PARAMS_NAMED, 'param0000', false);
1202 $DB->delete_records_select('tag_correlation', 'id '.$sql, $params);
1203 }
78defd5c 1204}
844f9c15 1205
78defd5c 1206/**
bcdcee90 1207 * This function processes a tag correlation and makes changes in the database as required.
78defd5c 1208 *
bcdcee90 1209 * The tag correlation object needs have both a tagid property and a correlatedtags property that is an array.
78defd5c 1210 *
bcdcee90
GGC
1211 * @package core_tag
1212 * @access private
1213 * @param stdClass $tagcorrelation
1214 * @return int/bool The id of the tag correlation that was just processed or false.
78defd5c
SH
1215 */
1216function tag_process_computed_correlation(stdClass $tagcorrelation) {
1217 global $DB;
db32b054 1218
78defd5c
SH
1219 // You must provide a tagid and correlatedtags must be set and be an array
1220 if (empty($tagcorrelation->tagid) || !isset($tagcorrelation->correlatedtags) || !is_array($tagcorrelation->correlatedtags)) {
1221 return false;
3d436d8a 1222 }
78defd5c 1223
78defd5c
SH
1224 $tagcorrelation->correlatedtags = join(',', $tagcorrelation->correlatedtags);
1225 if (!empty($tagcorrelation->id)) {
1226 // The tag correlation already exists so update it
1227 $DB->update_record('tag_correlation', $tagcorrelation);
1228 } else {
1229 // This is a new correlation to insert
2650c547 1230 $tagcorrelation->id = $DB->insert_record('tag_correlation', $tagcorrelation);
78defd5c 1231 }
2650c547 1232 return $tagcorrelation->id;
db32b054 1233}
1234
1235/**
1236 * Tasks that should be performed at cron time
bcdcee90
GGC
1237 *
1238 * @package core_tag
1239 * @access private
db32b054 1240 */
1241function tag_cron() {
1242 tag_compute_correlations();
0f5e5f5c 1243 tag_cleanup();
db32b054 1244}
1245
0f039283 1246/**
1247 * Search for tags with names that match some text
1248 *
bcdcee90
GGC
1249 * @package core_tag
1250 * @access private
1251 * @param string $text escaped string that the tag names will be matched against
1252 * @param bool $ordered If true, tags are ordered by their popularity. If false, no ordering.
1253 * @param int/string $limitfrom (optional, required if $limitnum is set) return a subset of records, starting at this point.
1254 * @param int/string $limitnum (optional, required if $limitfrom is set) return a subset comprising this many records.
1255 * @return array/boolean an array of objects, or false if no records were found or an error occured.
0f039283 1256 */
1257function tag_find_tags($text, $ordered=true, $limitfrom='', $limitnum='') {
f7ed2687 1258 global $DB;
0f039283 1259
7c2cc9c8
PS
1260 $norm = tag_normalize($text, TAG_CASE_LOWER);
1261 $text = array_shift($norm);
0f039283 1262
1263 if ($ordered) {
f7ed2687 1264 $query = "SELECT tg.id, tg.name, tg.rawname, COUNT(ti.id) AS count
1265 FROM {tag} tg LEFT JOIN {tag_instance} ti ON tg.id = ti.tagid
1266 WHERE tg.name LIKE ?
1267 GROUP BY tg.id, tg.name, tg.rawname
1268 ORDER BY count DESC";
0f039283 1269 } else {
f7ed2687 1270 $query = "SELECT tg.id, tg.name, tg.rawname
1271 FROM {tag} tg
1272 WHERE tg.name LIKE ?";
0f039283 1273 }
f7ed2687 1274 $params = array("%{$text}%");
1275 return $DB->get_records_sql($query, $params, $limitfrom , $limitnum);
0f039283 1276}
1277
986dca60 1278/**
db32b054 1279 * Get the name of a tag
986dca60 1280 *
bcdcee90
GGC
1281 * @package core_tag
1282 * @access private
1283 * @param mixed $tagids the id of the tag, or an array of ids
1284 * @return mixed string name of one tag, or id-indexed array of strings
db32b054 1285 */
1286function tag_get_name($tagids) {
f7ed2687 1287 global $DB;
3d436d8a 1288
f7ed2687 1289 if (!is_array($tagids)) {
1290 if ($tag = $DB->get_record('tag', array('id'=>$tagids))) {
1291 return $tag->name;
1292 }
1293 return false;
db32b054 1294 }
c933a060 1295
db32b054 1296 $tag_names = array();
986dca60 1297 foreach($DB->get_records_list('tag', 'id', $tagids) as $tag) {
db32b054 1298 $tag_names[$tag->id] = $tag->name;
1299 }
c933a060 1300
db32b054 1301 return $tag_names;
c933a060 1302}
1303
1304/**
bcdcee90
GGC
1305 * Returns the correlated tags of a tag, retrieved from the tag_correlation table. Make sure cron runs, otherwise the table will be
1306 * empty and this function won't return anything.
c933a060 1307 *
bcdcee90
GGC
1308 * @package core_tag
1309 * @access private
1310 * @param int $tag_id is a single tag id
1311 * @param int $limitnum this parameter does not appear to have any function???
1312 * @return array an array of tag objects or an empty if no correlated tags are found
c933a060 1313 */
db32b054 1314function tag_get_correlated($tag_id, $limitnum=null) {
f7ed2687 1315 global $DB;
3d436d8a 1316
f7ed2687 1317 $tag_correlation = $DB->get_record('tag_correlation', array('tagid'=>$tag_id));
c933a060 1318
db32b054 1319 if (!$tag_correlation || empty($tag_correlation->correlatedtags)) {
1320 return array();
c933a060 1321 }
986dca60 1322
73c32e86 1323 // this is (and has to) return the same fields as the query in tag_get_tags
638cf615 1324 $sql = "SELECT DISTINCT tg.id, tg.tagtype, tg.name, tg.rawname, tg.flag, ti.ordering
e2a64d83 1325 FROM {tag} tg
638cf615 1326 INNER JOIN {tag_instance} ti ON tg.id = ti.tagid
e2a64d83
SH
1327 WHERE tg.id IN ({$tag_correlation->correlatedtags})";
1328 $result = $DB->get_records_sql($sql);
1329 if (!$result) {
db32b054 1330 return array();
c933a060 1331 }
986dca60 1332
db32b054 1333 return $result;
c933a060 1334}
1335
c933a060 1336/**
db32b054 1337 * Function that normalizes a list of tag names.
c933a060 1338 *
bcdcee90
GGC
1339 * @package core_tag
1340 * @access private
1341 * @param array/string $rawtags array of tags, or a single tag.
1342 * @param int $case case to use for returned value (default: lower case). Either TAG_CASE_LOWER (default) or TAG_CASE_ORIGINAL
1343 * @return array lowercased normalized tags, indexed by the normalized tag, in the same order as the original array.
1344 * (Eg: 'Banana' => 'banana').
c933a060 1345 */
db32b054 1346function tag_normalize($rawtags, $case = TAG_CASE_LOWER) {
1347
0f039283 1348 // cache normalized tags, to prevent costly repeated calls to clean_param
db32b054 1349 static $cleaned_tags_lc = array(); // lower case - use for comparison
1350 static $cleaned_tags_mc = array(); // mixed case - use for saving to database
c933a060 1351
db32b054 1352 if ( !is_array($rawtags) ) {
1353 $rawtags = array($rawtags);
1354 }
c933a060 1355
db32b054 1356 $result = array();
1357 foreach($rawtags as $rawtag) {
1358 $rawtag = trim($rawtag);
1359 if (!$rawtag) {
1360 continue;
1361 }
1362 if ( !array_key_exists($rawtag, $cleaned_tags_lc) ) {
2f1e464a 1363 $cleaned_tags_lc[$rawtag] = core_text::strtolower( clean_param($rawtag, PARAM_TAG) );
db32b054 1364 $cleaned_tags_mc[$rawtag] = clean_param($rawtag, PARAM_TAG);
1365 }
986dca60 1366 if ( $case == TAG_CASE_LOWER ) {
db32b054 1367 $result[$rawtag] = $cleaned_tags_lc[$rawtag];
1368 } else { // TAG_CASE_ORIGINAL
1369 $result[$rawtag] = $cleaned_tags_mc[$rawtag];
1370 }
1371 }
986dca60 1372
db32b054 1373 return $result;
c933a060 1374}
1375
1376/**
bcdcee90 1377 * Count how many records are tagged with a specific tag.
c933a060 1378 *
bcdcee90
GGC
1379 * @package core_tag
1380 * @access private
1381 * @param string $record_type record to look for ('post', 'user', etc.)
1382 * @param int $tagid is a single tag id
1383 * @return int number of mathing tags.
c933a060 1384 */
0f039283 1385function tag_record_count($record_type, $tagid) {
f7ed2687 1386 global $DB;
1387 return $DB->count_records('tag_instance', array('itemtype'=>$record_type, 'tagid'=>$tagid));
0f039283 1388}
c933a060 1389
0f039283 1390/**
986dca60 1391 * Determine if a record is tagged with a specific tag
0f039283 1392 *
bcdcee90
GGC
1393 * @package core_tag
1394 * @access private
1395 * @param string $record_type the record type to look for
1396 * @param int $record_id the record id to look for
1397 * @param string $tag a tag name
1398 * @return bool/int true if it is tagged, 0 (false) otherwise
0f039283 1399 */
1400function tag_record_tagged_with($record_type, $record_id, $tag) {
f7ed2687 1401 global $DB;
0f039283 1402 if ($tagid = tag_get_id($tag)) {
f7ed2687 1403 return $DB->count_records('tag_instance', array('itemtype'=>$record_type, 'itemid'=>$record_id, 'tagid'=>$tagid));
c933a060 1404 } else {
0f039283 1405 return 0; // tag doesn't exist
c933a060 1406 }
c933a060 1407}
1408
1409/**
6298494d 1410 * Flag a tag as inappropriate.
986dca60 1411 *
6298494d 1412 * @param int|array $tagids a single tagid, or an array of tagids
c933a060 1413 */
db32b054 1414function tag_set_flag($tagids) {
f7ed2687 1415 global $DB;
1416
6298494d
MN
1417 $tagids = (array) $tagids;
1418
1419 // Use the tagids to create a select statement to be used later.
1420 list($tagsql, $tagparams) = $DB->get_in_or_equal($tagids, SQL_PARAMS_NAMED);
1421
1422 // Update all the tags to flagged.
1423 $sql = "UPDATE {tag}
1424 SET flag = flag + 1, timemodified = :time
1425 WHERE id $tagsql";
1426
1427 // Update all the tags.
1428 $DB->execute($sql, array_merge(array('time' => time()), $tagparams));
1429
1430 // Get all the tags.
1431 if ($tags = $DB->get_records_select('tag', 'id '. $tagsql, $tagparams, 'id ASC')) {
1432 // Loop through and fire an event for each tag that it was flagged.
1433 foreach ($tags as $tag) {
1434 $event = \core\event\tag_flagged::create(array(
1435 'objectid' => $tag->id,
1436 'relateduserid' => $tag->userid,
1437 'context' => context_system::instance(),
1438 'other' => array(
1439 'name' => $tag->name,
1440 'rawname' => $tag->rawname
1441 )
1442
1443 ));
1444 $event->add_record_snapshot('tag', $tag);
1445 $event->trigger();
1446 }
c933a060 1447 }
1448}
1449
986dca60 1450/**
097bd4cd 1451 * Remove the inappropriate flag on a tag.
986dca60 1452 *
097bd4cd 1453 * @param int|array $tagids a single tagid, or an array of tagids
c933a060 1454 */
db32b054 1455function tag_unset_flag($tagids) {
f7ed2687 1456 global $DB;
d4be9d6d 1457
097bd4cd
MN
1458 $tagids = (array) $tagids;
1459
1460 // Use the tagids to create a select statement to be used later.
1461 list($tagsql, $tagparams) = $DB->get_in_or_equal($tagids, SQL_PARAMS_NAMED);
1462
1463 // Update all the tags to unflagged.
1464 $sql = "UPDATE {tag}
1465 SET flag = 0, timemodified = :time
1466 WHERE id $tagsql";
1467
1468 // Update all the tags.
1469 $DB->execute($sql, array_merge(array('time' => time()), $tagparams));
1470
1471 // Get all the tags.
1472 if ($tags = $DB->get_records_select('tag', 'id '. $tagsql, $tagparams, 'id ASC')) {
1473 // Loop through and fire an event for each tag that it was unflagged.
1474 foreach ($tags as $tag) {
1475 $event = \core\event\tag_unflagged::create(array(
1476 'objectid' => $tag->id,
1477 'relateduserid' => $tag->userid,
1478 'context' => context_system::instance(),
1479 'other' => array(
1480 'name' => $tag->name,
1481 'rawname' => $tag->rawname
1482 )
1483 ));
1484 $event->add_record_snapshot('tag', $tag);
1485 $event->trigger();
1486 }
ab86d9c7 1487 }
c933a060 1488}
b1627a92 1489
b1627a92
DC
1490/**
1491 * Return a list of page types
bcdcee90
GGC
1492 *
1493 * @package core_tag
1494 * @access private
1495 * @param string $pagetype current page type
1496 * @param stdClass $parentcontext Block's parent context
1497 * @param stdClass $currentcontext Current context of block
b1627a92 1498 */
b38e2e28 1499function tag_page_type_list($pagetype, $parentcontext, $currentcontext) {
b1627a92
DC
1500 return array(
1501 'tag-*'=>get_string('page-tag-x', 'tag'),
1502 'tag-index'=>get_string('page-tag-index', 'tag'),
1503 'tag-search'=>get_string('page-tag-search', 'tag'),
1504 'tag-manage'=>get_string('page-tag-manage', 'tag')
1505 );
1506}