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Close open HTML tags in a string

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南方客
南方客 2020-11-28 11:21

Situation is a string that results in something like this:

This is some text and here is a bold text then the post stop here....
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9条回答
  • 醉话见心
    2020-11-28 11:46

    Here is a function i've used before, which works pretty well:

    function closetags($html) {
    preg_match_all('#<(?!meta|img|br|hr|input\b)\b([a-z]+)(?: .*)?(?<![/|/ ])>#iU', $html, $result);
    $openedtags = $result[1];
    preg_match_all('#</([a-z]+)>#iU', $html, $result);
    $closedtags = $result[1];
    $len_opened = count($openedtags);
    if (count($closedtags) == $len_opened) {
        return $html;
    }
    $openedtags = array_reverse($openedtags);
    for ($i=0; $i < $len_opened; $i++) {
        if (!in_array($openedtags[$i], $closedtags)) {
            $html .= '</'.$openedtags[$i].'>';
        } else {
            unset($closedtags[array_search($openedtags[$i], $closedtags)]);
        }
    }
    return $html;
}

    Personally though, I would not do it using regexp but a library such as Tidy. This would be something like the following:

    $str = '<p>This is some text and here is a <strong>bold text then the post stop here....</p>';
$tidy = new Tidy();
$clean = $tidy->repairString($str, array(
    'output-xml' => true,
    'input-xml' => true
));
echo $clean;
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  • 春和景丽
    2020-11-28 11:46

    A small modification to the original answer...while the original answer stripped tags correctly. I found that during my truncation, I could end up with chopped up tags. For example:

    This text has some <b>in it</b>

    Truncating at character 21 results in:

    This text has some <

    The following code, builds on the next best answer and fixes this.

    function truncateHTML($html, $length)
{
    $truncatedText = substr($html, $length);
    $pos = strpos($truncatedText, ">");
    if($pos !== false)
    {
        $html = substr($html, 0,$length + $pos + 1);
    }
    else
    {
        $html = substr($html, 0,$length);
    }

    preg_match_all('#<(?!meta|img|br|hr|input\b)\b([a-z]+)(?: .*)?(?<![/|/ ])>#iU', $html, $result);
    $openedtags = $result[1];

    preg_match_all('#</([a-z]+)>#iU', $html, $result);
    $closedtags = $result[1];

    $len_opened = count($openedtags);

    if (count($closedtags) == $len_opened)
    {
        return $html;
    }

    $openedtags = array_reverse($openedtags);
    for ($i=0; $i < $len_opened; $i++)
    {
        if (!in_array($openedtags[$i], $closedtags))
        {
            $html .= '</'.$openedtags[$i].'>';
        }
        else
        {
            unset($closedtags[array_search($openedtags[$i], $closedtags)]);
        }
    }


    return $html;
}


$str = "This text has <b>bold</b> in it</b>";
print "Test 1 - Truncate with no tag: " . truncateHTML($str, 5) . "<br>\n";
print "Test 2 - Truncate at start of tag: " . truncateHTML($str, 20) . "<br>\n";
print "Test 3 - Truncate in the middle of a tag: " . truncateHTML($str, 16) . "<br>\n";
print "Test 4: - Truncate with less text: " . truncateHTML($str, 300) . "<br>\n";

    Hope it helps someone out there.

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  • 渐次进展
    2020-11-28 11:48

    And what about using PHP's native DOMDocument class? It inherently parses HTML and corrects syntax errors... E.g.:

    $fragment = "<article><h3>Title</h3><p>Unclosed";
$doc = new DOMDocument();
$doc->loadHTML($fragment);
$correctFragment = $doc->getElementsByTagName('body')->item(0)->C14N();
echo $correctFragment;

    However, there are several disadvantages of this approach. Firstly, it wraps the original fragment within the <body> tag. You can get rid of it easily by something like (preg_)replace() or by substituting the ...->C14N() function by some custom innerHTML() function, as suggested for example at http://php.net/manual/en/book.dom.php#89718. The second pitfall is that PHP throws an 'invalid tag in Entity' warning if HTML5 or custom tags are used (nevertheless, it will still proceed correctly).

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  • 面向向阳花
    2020-11-28 11:49

    Using a regular expression isn't an ideal approach for this. You should use an html parser instead to create a valid document object model.

    As a second option, depending on what you want, you could use a regex to remove any and all html tags from your string before you put it in the <p> tag.

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  • 予麋鹿
    2020-11-28 11:53

    There are numerous other variables that need to be addressed to give a full solution, but are not covered by your question.

    However, I would suggest using something like HTML Tidy and in particular the repairFile or repaireString methods.

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  • 眼角桃花
    2020-11-28 11:56

    This PHP method always worked for me. It will close all un-closed HTML tags.

    function closetags($html) {
    preg_match_all('#<([a-z]+)(?: .*)?(?<![/|/ ])>#iU', $html, $result);
    $openedtags = $result[1];

    preg_match_all('#</([a-z]+)>#iU', $html, $result);
    $closedtags = $result[1];
    $len_opened = count($openedtags);
    if (count($closedtags) == $len_opened) {
        return $html;
    }
    $openedtags = array_reverse($openedtags);
    for ($i=0; $i < $len_opened; $i++) {
        if (!in_array($openedtags[$i], $closedtags)){
            $html .= '</'.$openedtags[$i].'>';
        } else {
            unset($closedtags[array_search($openedtags[$i], $closedtags)]);
        }
    }
    return $html;
}
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