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Home Manuali Programmazione Troncare un testo HTML ad una determinata lunghezza e tenendo conto dei tag

Troncare un testo HTML ad una determinata lunghezza e tenendo conto dei tag

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Script in PHP per troncare un testo HTML ad una determinata lunghezza e tenendo conto dei tag al suo interno, quindi evitando di interrompere il testo nel bel mezzo di un tag.

/**
 * Truncates text.
 *
 * Cuts a string to the length of $length and replaces the last characters
 * with the ending if the text is longer than length.
 *
 * @param string  $text String to truncate.
 * @param integer $length Length of returned string, including ellipsis.
 * @param string  $ending Ending to be appended to the trimmed string.
 * @param boolean $exact If false, $text will not be cut mid-word
 * @param boolean $considerHtml If true, HTML tags would be handled correctly
 * @return string Trimmed string.
 */
  function truncate($text, $length = 100, $ending = '...', $exact = true, $considerHtml = false) {
    if ($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 (f.e. <br/>)
          if (preg_match('/^<(\s*.+?\/\s*|\s*(img|br|input|hr|area|base|basefont|col|frame|isindex|link|meta|param)(\s.+?)?)>$/is', $line_matchings[1])) {
            // do nothing
          // if tag is a closing tag (f.e. </b>)
          } else if (preg_match('/^<\s*\/([^\s]+?)\s*>$/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 (f.e. <b>)
          } 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('/&amp;[0-9a-z]{2,8};|&amp;#[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('/&amp;[0-9a-z]{2,8};|&amp;#[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;
  }
 

Questa parte di codice proviene da CakePHP.

Un esempio molto meno complicato è la seguente funzione:

// trim string function
function mytrim($string,$trim_length,$strip_string,$dots){
  if ($strip_string) {
    $input = strip_tags(preg_replace('`\[[^\]]*\]`','',$string));
  }
  //String already shorter than trim length
  if (strlen($string) <= $trim_length) {
    return $string;
  }
  //find last space within given length of string
  $last_space = strrpos(substr($string, 0, $trim_length), ' ');
  $trim_string = substr($string, 0, $last_space); 
  //add dots (...)
  if ($dots) {
    $trim_string .= '...';
  }
  return $string;
}
 
 
Ultimo aggiornamento ( Domenica 05 Febbraio 2012 08:12 )  
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