缩短文本而不分割单词或破坏html标签

Question

我试图在236个字符之后切断文本,而不会将单词切成两半并保留html标签.这就是我现在正在使用的:

$shortdesc = $_helper->productAttribute($_product, $_product->getShortDescription(), 'short_description');
$lenght = 236;
echo substr($shortdesc, 0, strrpos(substr($shortdesc, 0, $lenght), " "));

虽然这在大多数情况下都有效,但它不会尊重html标签.所以例如这个文本:

Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. <strong>Stet clita kasd gubergren</strong>

标签仍然打开时会被切断.有没有办法在236个字符之后切断文本但是尊重html标签？

Answer 1

我遇到的最佳解决方案来自CakePHP框架TextHelper类

这是方法

/**
* 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.
*
* ### Options:
*
* - `ending` Will be used as Ending and appended to the trimmed string
* - `exact` If false, $text will not be cut mid-word
* - `html` If true, HTML tags would be handled correctly
*
* @param string  $text String to truncate.
* @param integer $length Length of returned string, including ellipsis.
* @param array $options An array of html attributes and options.
* @return string Trimmed string.
* @access public
* @link http://book.cakephp.org/view/1469/Text#truncate-1625
*/
function truncate($text, $length = 100, $options = array()) {
    $default = array(
        'ending' => '...', 'exact' => true, 'html' => false
    );
    $options = array_merge($default, $options);
    extract($options);

    if ($html) {
        if (mb_strlen(preg_replace('/<.*?>/', '', $text)) <= $length) {
            return $text;
        }
        $totalLength = mb_strlen(strip_tags($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, $length - mb_strlen($ending));
        }
    }
    if (!$exact) {
        $spacepos = mb_strrpos($truncate, ' ');
        if (isset($spacepos)) {
            if ($html) {
                $bits = mb_substr($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 ($html) {
        foreach ($openTags as $tag) {
            $truncate .= '</'.$tag.'>';
        }
    }

    return $truncate;
}

其他框架可能对此问题有类似(或不同)的解决方案,因此您也可以查看它们.我对Cake的熟悉促使我链接到他们的解决方案

编辑:

刚刚在我正在使用OP文本的app中测试了这个方法

<?php 
echo truncate(
'Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. <strong>Stet clita kasd gubergren</strong>', 
236, 
array('html' => true, 'ending' => '')); 
?>

输出:

Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. <strong>Stet clita kasd gubegre</strong>

请注意,输出仅在完成最后一个单词时停止,但包括完整的强标记

Answer 2

这应该这样做:

class Html
{
    protected
        $reachedLimit = false,
        $totalLen = 0,
        $maxLen = 25,
        $toRemove = array();

    public static function trim($html, $maxLen = 25)
    {

        $dom = new DomDocument();

        if (version_compare(PHP_VERSION, '5.4.0') < 0) {
            $dom->loadHTML($html);
        } else {
            $dom->loadHTML($html, LIBXML_HTML_NOIMPLIED | LIBXML_HTML_NODEFDTD);
        }

        $instance = new static();
        $toRemove = $instance->walk($dom, $maxLen);

        // remove any nodes that exceed limit
        foreach ($toRemove as $child) {
            $child->parentNode->removeChild($child);
        }

        // remove wrapper tags added by DD (doctype, html...)
        if (version_compare(PHP_VERSION, '5.4.0') < 0) {
            // http://stackoverflow.com/a/6953808/1058140
            $dom->removeChild($dom->firstChild);
            $dom->replaceChild($dom->firstChild->firstChild->firstChild, $dom->firstChild);

            return $dom->saveHTML();
        }

        return $dom->saveHTML();
    }

    protected function walk(DomNode $node, $maxLen)
    {

        if ($this->reachedLimit) {
            $this->toRemove[] = $node;
        } else {
            // only text nodes should have text,
            // so do the splitting here
            if ($node instanceof DomText) {
                $this->totalLen += $nodeLen = strlen($node->nodeValue);

                // use mb_strlen / mb_substr for UTF-8 support
                if ($this->totalLen > $maxLen) {
                    $node->nodeValue = substr($node->nodeValue, 0, $nodeLen - ($this->totalLen - $maxLen)) . '...';
                    $this->reachedLimit = true;
                }
            }

            // if node has children, walk its child elements
            if (isset($node->childNodes)) {
                foreach ($node->childNodes as $child) {
                    $this->walk($child, $maxLen);
                }
            }
        }

        return $this->toRemove;
    }
}

使用如下: $str = Html::trim($str, 236);

(这里演示)

这与cakePHP的正则表达式解决方案之间的性能比较

差异非常小,而且在非常大的字符串大小下,DomDocument实际上更快.在我看来,可靠性比节省几微秒更重要.

Answer 3

您可以采用 XML 方法并将元素推送到字符串 var，直到字符串的长度超过 236

示例代码？

for each node // text or tag
  push to the string var

  if string length > 236
    break

endfor

用于在 PHP 中解析 HTML http://simplehtmldom.sourceforge.net/