Tronquer un texte en conservant les tags HTML en PHP

Voici une fonction plutôt pratique qui vous permet de tronquer du texte tout en tenant compte du compte code HTML potentiel. Cette fonction est issue du framework CakePHP. Pour la description des paramètres, ils sont renseignés dans les commentaires de la fonction.

/**
 * 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 mixed $ending If string, will be used as Ending and appended to the trimmed string. Can also be an associative array that can contain the last three params of this method.
 * @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, $considerHtml = false) {
	if (is_array($ending)) {
		extract($ending);
	}
	if ($considerHtml) {
		if (mb_strlen(preg_replace('/<.*?>/', '', $text)) <= $length) {
			return $text;
		}
		$totalLength = mb_strlen($ending);
		$openTags = array();
		$truncate = '';
		preg_match_all('/(<\/?([\w+]+)[^>]*>)?([^<>]*)/', $text, $tags, PREG_SET_ORDER);
		foreach ($tags as $tag) {
			if (!preg_match('/img|br|input|hr|area|base|basefont|col|frame|isindex|link|meta|param/s', $tag[2])) {
				if (preg_match('/<[\w]+[^>]*>/s', $tag[0])) {
					array_unshift($openTags, $tag[2]);
				} else if (preg_match('/<\/([\w]+)[^>]*>/s', $tag[0], $closeTag)) {
					$pos = array_search($closeTag[1], $openTags);
					if ($pos !== false) {
						array_splice($openTags, $pos, 1);
					}
				}
			}
			$truncate .= $tag[1];

			$contentLength = mb_strlen(preg_replace('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|&#x[0-9a-f]{1,6};/i', ' ', $tag[3]));
			if ($contentLength + $totalLength > $length) {
				$left = $length - $totalLength;
				$entitiesLength = 0;
				if (preg_match_all('/&[0-9a-z]{2,8};|&#[0-9]{1,7};|&#x[0-9a-f]{1,6};/i', $tag[3], $entities, PREG_OFFSET_CAPTURE)) {
					foreach ($entities[0] as $entity) {
						if ($entity[1] + 1 - $entitiesLength <= $left) {
							$left--;
							$entitiesLength += mb_strlen($entity[0]);
						} else {
							break;
						}
					}
				}

				$truncate .= mb_substr($tag[3], 0 , $left + $entitiesLength);
				break;
			} else {
				$truncate .= $tag[3];
				$totalLength += $contentLength;
			}
			if ($totalLength >= $length) {
				break;
			}
		}

	} else {
		if (mb_strlen($text) <= $length) {
			return $text;
		} else {
			$truncate = mb_substr($text, 0, $length - strlen($ending));
		}
	}
	if (!$exact) {
		$spacepos = mb_strrpos($truncate, ' ');
		if (isset($spacepos)) {
			if ($considerHtml) {
				$bits = mb_substr($truncate, $spacepos);
				preg_match_all('/<\/([a-z]+)>/', $bits, $droppedTags, PREG_SET_ORDER);
				if (!empty($droppedTags)) {
					foreach ($droppedTags as $closingTag) {
						if (!in_array($closingTag[1], $openTags)) {
							array_unshift($openTags, $closingTag[1]);
						}
					}
				}
			}
			$truncate = mb_substr($truncate, 0, $spacepos);
		}
	}

	$truncate .= $ending;

	if ($considerHtml) {
		foreach ($openTags as $tag) {
			$truncate .= '</'.$tag.'>';
		}
	}

	return $truncate;
}

Voici un jeu de test que vous pouvez mettre en place pour comprendre comment fonctionne cette fonction :

$text1 = 'The quick brown fox jumps over the lazy dog';
$text2 = 'Heizölrückstoßabdämpfung';
$text3 = '<b>&copy; 2005-2007, Cake Software Foundation, Inc.</b><br />written by Alexander Wegener';
$text4 = '<img src="mypic.jpg"> This image tag is not XHTML conform!<br><hr/><b>But the following image tag should be conform <img src="mypic.jpg" alt="Me, myself and I" /></b><br />Great, or?';
$text5 = '0<b>1<i>2<span class="myclass">3</span>4<u>5</u>6</i>7</b>8<b>9</b>0';

// normal truncate tests
echo htmlentities(truncate($text1, 15)).'<br/>';
echo htmlentities(truncate($text1, 15, '...', false)).'<br/>';
echo htmlentities(truncate($text1, 100)).'<br/>';
echo htmlentities(truncate($text2, 10, '...')).'<br/>';
echo htmlentities(truncate($text2, 10, '...', false)).'<br/>';
echo htmlentities(truncate($text3, 20)).'<br/>';
echo htmlentities(truncate($text4, 15)).'<br/>';
echo htmlentities(truncate($text5, 6, '')).'<br/>';

echo '---------------------------------------------<br/>';

// html considering tests
echo htmlentities(truncate($text1, 15, '...', true, true)).'<br/>';
echo htmlentities(truncate($text1, 15, '...', false, true)).'<br/>';
echo htmlentities(truncate($text2, 10, '...', true, true)).'<br/>';
echo htmlentities(truncate($text2, 10, '...', false, true)).'<br/>';
echo htmlentities(truncate($text3, 20, '...', true, true)).'<br/>';
echo htmlentities(truncate($text4, 15, '...', true, true)).'<br/>';
echo htmlentities(truncate($text4, 45, '...', true, true)).'<br/>';
echo htmlentities(truncate($text4, 90, '...', true, true)).'<br/>';
echo htmlentities(truncate($text5, 6, '', true, true)).'<br/>';

Ce qui fournit le résultat suivant :

The quick br...
The quick...
The quick brown fox jumps over the lazy dog
Heiz&ou...
...
<b>&copy; 2005-20...
<img src="my...
0<b>1<
---------------------------------------------
The quick br...
The quick...
Heiz&ouml;lr...
...
<b>&copy; 2005-2007, Cake...</b>
<img src="mypic.jpg"> This image ...
<img src="mypic.jpg"> This image tag is not XHTML conform!<br><hr/><b>But t...</b>
<img src="mypic.jpg"> This image tag is not XHTML conform!<br><hr/><b>But the following image tag should be conform <img src="mypic.jpg" alt="Me, myself and I" /></b><br />Grea...
0<b>1<i>2<span class="myclass">3</span>4<u>5</u></i></b>

Remarque : vous devez avoir installé l’extension mbstring.

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