HTML – String mit Tags kürzen

Ein HTML-String der HTML-Tag enthält, kann nicht einfach mit substr gekürzt werden, da Tags so einfach abgeschnitten werden.

Eine feine Funktion dafür findet man auf github:

public static function truncate($text, $length = 100, $ending = '...', $exact = false, $considerHtml = true) {
    if ($considerHtml) {
      // if the plain text is shorter than the maximum length, return the whole text
      if (strlen(preg_replace('/<.*?>/', '', $text)) <= $length) {
        return $text;
      }
      // splits all html-tags to scanable lines
      preg_match_all('/(<.+?>)?([^<>]*)/s', $text, $lines, PREG_SET_ORDER);
      $total_length = strlen($ending);
      $open_tags = array();
      $truncate = '';
      foreach ($lines as $line_matchings) {
        // if there is any html-tag in this line, handle it and add it (uncounted) to the output
        if (!empty($line_matchings[1])) {
          // if it's an "empty element" with or without xhtml-conform closing slash
          if (preg_match('/^<(\s*.+?\/\s*|\s*(img|br|input|hr|area|base|basefont|col|frame|isindex|link|meta|param)(\s.+?)?)>$/is', $line_matchings[1])) {
            // do nothing
            // if tag is a closing tag
          } else if (preg_match('/^<\s*\/([^\s]+?)\s*>$/s', $line_matchings[1], $tag_matchings)) {
            // delete tag from $open_tags list
            $pos = array_search($tag_matchings[1], $open_tags);
            if ($pos !== false) {
              unset($open_tags[$pos]);
            }
            // if tag is an opening tag
          } else if (preg_match('/^<\s*([^\s>!]+).*?>$/s', $line_matchings[1], $tag_matchings)) {
            // add tag to the beginning of $open_tags list
            array_unshift($open_tags, strtolower($tag_matchings[1]));
          }
          // add html-tag to $truncate'd text
          $truncate .= $line_matchings[1];
        }
        // calculate the length of the plain text part of the line; handle entities as one character
        $content_length = strlen(preg_replace('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|[0-9a-f]{1,6};/i', ' ', $line_matchings[2]));
        if ($total_length+$content_length> $length) {
          // the number of characters which are left
          $left = $length - $total_length;
          $entities_length = 0;
          // search for html entities
          if (preg_match_all('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|[0-9a-f]{1,6};/i', $line_matchings[2], $entities, PREG_OFFSET_CAPTURE)) {
            // calculate the real length of all entities in the legal range
            foreach ($entities[0] as $entity) {
              if ($entity[1]+1-$entities_length <= $left) {
                $left--;
                $entities_length += strlen($entity[0]);
              } else {
                // no more characters left
                break;
              }
            }
          }
          $truncate .= substr($line_matchings[2], 0, $left+$entities_length);
          // maximum lenght is reached, so get off the loop
          break;
        } else {
          $truncate .= $line_matchings[2];
          $total_length += $content_length;
        }
        // if the maximum length is reached, get off the loop
        if($total_length>= $length) {
          break;
        }
      }
    } else {
      if (strlen($text) <= $length) {
        return $text;
      } else {
        $truncate = substr($text, 0, $length - strlen($ending));
      }
    }
    // if the words shouldn't be cut in the middle...
    if (!$exact) {
      // ...search the last occurance of a space...
      $spacepos = strrpos($truncate, ' ');
      if (isset($spacepos)) {
        // ...and cut the text in this position
        $truncate = substr($truncate, 0, $spacepos);
      }
    }
    // add the defined ending to the text
    $truncate .= $ending;
    if($considerHtml) {
      // close all unclosed html-tags
      foreach ($open_tags as $tag) {
        $truncate .= '</' . $tag . '>';
      }
    }
    return $truncate;
  }

Quelle: bereits gelöscht