wcfsetup/install/files/lib/system/MetaTagHandler.class.php

   1 <?php
   2 namespace wcf\system;
   3 use wcf\util\StringUtil;
   4
   5 /**
   6  * Handles meta tags.
   7  *
   8  * @author      Alexander Ebert
   9  * @copyright   2001-2018 WoltLab GmbH
  10  * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  11  * @package     WoltLabSuite\Core\System\Message
  12  */
  13 class MetaTagHandler extends SingletonFactory implements \Countable, \Iterator {
  14         /**
  15          * current iterator index
  16          * @var integer
  17          */
  18         protected $index = 0;
  19
  20         /**
  21          * list of index to object relation
  22          * @var integer[]
  23          */
  24         protected $indexToObject = [];
  25
  26         /**
  27          * list of meta tags
  28          * @var array
  29          */
  30         protected $objects = [];
  31
  32         /**
  33          * @inheritDoc
  34          */
  35         protected function init() {
  36                 // set default tags
  37                 if ($value = WCF::getLanguage()->get(META_DESCRIPTION)) {
  38                         $this->addTag('description', 'description', $value);
  39                 }
  40                 if ($value = WCF::getLanguage()->get(META_KEYWORDS)) {
  41                         $this->addTag('keywords', 'keywords', $value);
  42                 }
  43                 if ($value = WCF::getLanguage()->get(PAGE_TITLE)) {
  44                         $this->addTag('og:site_name', 'og:site_name', $value, true);
  45                 }
  46                 if (OG_IMAGE) {
  47                         $this->addTag('og:image', 'og:image', (preg_match('~^https?://~', OG_IMAGE) ? OG_IMAGE : WCF::getPath() . OG_IMAGE), true);
  48                 }
  49                 if (FB_SHARE_APP_ID) {
  50                         $this->addTag('fb:app_id', 'fb:app_id', FB_SHARE_APP_ID, true);
  51                 }
  52         }
  53
  54         /**
  55          * Adds or replaces a meta tag.
  56          *
  57          * @param       string          $identifier
  58          * @param       string          $name
  59          * @param       string          $value
  60          * @param       boolean         $isProperty
  61          */
  62         public function addTag($identifier, $name, $value, $isProperty = false) {
  63                 if (!isset($this->objects[$identifier])) {
  64                         $this->indexToObject[] = $identifier;
  65                 }
  66
  67                 $this->objects[$identifier] = [
  68                         'isProperty' => $isProperty,
  69                         'name' => $name,
  70                         'value' => $value
  71                 ];
  72
  73                 // replace description if Open Graph Protocol tag was given
  74                 if ($name == 'og:description' && $value) {
  75                         $this->addTag('description', 'description', $value);
  76                 }
  77         }
  78
  79         /**
  80          * Removes a meta tag.
  81          *
  82          * @param       string          $identifier
  83          */
  84         public function removeTag($identifier) {
  85                 if (isset($this->objects[$identifier])) {
  86                         unset($this->objects[$identifier]);
  87
  88                         $this->indexToObject = array_keys($this->objects);
  89                 }
  90         }
  91
  92         /**
  93          * @inheritDoc
  94          */
  95         public function count() {
  96                 return count($this->objects);
  97         }
  98
  99         /**
 100          * @inheritDoc
 101          */
 102         public function current() {
 103                 $tag = $this->objects[$this->indexToObject[$this->index]];
 104
 105                 return '<meta ' . ($tag['isProperty'] ? 'property' : 'name') . '="' . $tag['name'] . '" content="' . StringUtil::encodeHTML($tag['value']) . '">';
 106         }
 107
 108         /**
 109          * CAUTION: This methods does not return the current iterator index,
 110          * rather than the object key which maps to that index.
 111          *
 112          * @see \Iterator::key()
 113          */
 114         public function key() {
 115                 return $this->indexToObject[$this->index];
 116         }
 117
 118         /**
 119          * @inheritDoc
 120          */
 121         public function next() {
 122                 ++$this->index;
 123         }
 124
 125         /**
 126          * @inheritDoc
 127          */
 128         public function rewind() {
 129                 $this->index = 0;
 130         }
 131
 132         /**
 133          * @inheritDoc
 134          */
 135         public function valid() {
 136                 return isset($this->indexToObject[$this->index]);
 137         }
 138 }