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

   1 <?php
   2 declare(strict_types=1);
   3 namespace wcf\system;
   4 use wcf\util\StringUtil;
   5
   6 /**
   7  * Handles meta tags.
   8  *
   9  * @author      Alexander Ebert
  10  * @copyright   2001-2018 WoltLab GmbH
  11  * @license     GNU Lesser General Public License <http://opensource.org/licenses/lgpl-license.php>
  12  * @package     WoltLabSuite\Core\System\Message
  13  */
  14 class MetaTagHandler extends SingletonFactory implements \Countable, \Iterator {
  15         /**
  16          * current iterator index
  17          * @var integer
  18          */
  19         protected $index = 0;
  20
  21         /**
  22          * list of index to object relation
  23          * @var integer[]
  24          */
  25         protected $indexToObject = [];
  26
  27         /**
  28          * list of meta tags
  29          * @var array
  30          */
  31         protected $objects = [];
  32
  33         /**
  34          * @inheritDoc
  35          */
  36         protected function init() {
  37                 // set default tags
  38                 if ($value = WCF::getLanguage()->get(META_DESCRIPTION)) {
  39                         $this->addTag('description', 'description', $value);
  40                 }
  41                 if ($value = WCF::getLanguage()->get(META_KEYWORDS)) {
  42                         $this->addTag('keywords', 'keywords', $value);
  43                 }
  44                 if ($value = WCF::getLanguage()->get(PAGE_TITLE)) {
  45                         $this->addTag('og:site_name', 'og:site_name', $value, true);
  46                 }
  47                 if (OG_IMAGE) {
  48                         $this->addTag('og:image', 'og:image', (preg_match('~^https?://~', OG_IMAGE) ? OG_IMAGE : WCF::getPath() . OG_IMAGE), true);
  49                 }
  50                 if (FB_SHARE_APP_ID) {
  51                         $this->addTag('fb:app_id', 'fb:app_id', FB_SHARE_APP_ID, true);
  52                 }
  53         }
  54
  55         /**
  56          * Adds or replaces a meta tag.
  57          *
  58          * @param       string          $identifier
  59          * @param       string          $name
  60          * @param       string          $value
  61          * @param       boolean         $isProperty
  62          */
  63         public function addTag($identifier, $name, $value, $isProperty = false) {
  64                 if (!isset($this->objects[$identifier])) {
  65                         $this->indexToObject[] = $identifier;
  66                 }
  67
  68                 $this->objects[$identifier] = [
  69                         'isProperty' => $isProperty,
  70                         'name' => $name,
  71                         'value' => $value
  72                 ];
  73
  74                 // replace description if Open Graph Protocol tag was given
  75                 if ($name == 'og:description' && $value) {
  76                         $this->addTag('description', 'description', $value);
  77                 }
  78         }
  79
  80         /**
  81          * Removes a meta tag.
  82          *
  83          * @param       string          $identifier
  84          */
  85         public function removeTag($identifier) {
  86                 if (isset($this->objects[$identifier])) {
  87                         unset($this->objects[$identifier]);
  88
  89                         $this->indexToObject = array_keys($this->objects);
  90                 }
  91         }
  92
  93         /**
  94          * @inheritDoc
  95          */
  96         public function count() {
  97                 return count($this->objects);
  98         }
  99
 100         /**
 101          * @inheritDoc
 102          */
 103         public function current() {
 104                 $tag = $this->objects[$this->indexToObject[$this->index]];
 105
 106                 return '<meta ' . ($tag['isProperty'] ? 'property' : 'name') . '="' . $tag['name'] . '" content="' . StringUtil::encodeHTML($tag['value']) . '">';
 107         }
 108
 109         /**
 110          * CAUTION: This methods does not return the current iterator index,
 111          * rather than the object key which maps to that index.
 112          *
 113          * @see \Iterator::key()
 114          */
 115         public function key() {
 116                 return $this->indexToObject[$this->index];
 117         }
 118
 119         /**
 120          * @inheritDoc
 121          */
 122         public function next() {
 123                 ++$this->index;
 124         }
 125
 126         /**
 127          * @inheritDoc
 128          */
 129         public function rewind() {
 130                 $this->index = 0;
 131         }
 132
 133         /**
 134          * @inheritDoc
 135          */
 136         public function valid() {
 137                 return isset($this->indexToObject[$this->index]);
 138         }
 139 }