我想替换所有未出现在<…>中的字符串

Question

I want to do server-side highlighting of searched words, by processing the output before sending it out.

The reasoning behind "server-side" is:

1) Javascript highlighting for unicode text sucks. 2) \\b not working with unicode (at least in JS, AFAIK). 3) No lookbehind support in JS.

I was using the function below, but last night realized that the first part which was written to skip <...> is not working.

public function ss_highlight($terms, $buf)
{
    if (empty($terms))  {
        return $buf;;
    }

    /* sort before using length for better match */
    usort($terms, function($a, $b) {
        return mb_strlen($b) - mb_strlen($a);
    });
    $str_terms = implode('|', $terms);

    /* server side highlighter */
    $buf = preg_replace('/(<[^>]+>)*(?<=[\s|:|\-|>|\(|\)|\.|,|\/|^])('.$str_terms.')(?=[\s|:|\-|<|\(|\)|\.|,|\/]|$)/i', '$1<span class="highlight">$2</span>', $buf);

    return $buf;
}

Any ideas would be appreciated.

Regards.

PS: I saw some similar things in Replacing all occurences of a specific word which are not enclosed with the words OPEN and CLOSE? but cannot figure out how to fit this to my requirements.

Answer 1

DO NOT try to parse HTML with regular expressions! Use a HTML Parser!

See Highlight Search Terms in PHP without breaking anchor tags using regex and RegEx match open tags except XHTML self-contained tags

Answer 2

Actually, everybody knows using regex for HTML is a bad idea, but in this case, we really do not need the DOM, because we just want to replace some text aoccuring outside of any < ... >.

This solution seems to work fine for me:

public function ss_highlight($terms, $buf)
{
    if (empty($terms))  {
        return $buf;;
    }

    /* sort before using length for better match */
    usort($terms, function($a, $b) {
        return mb_strlen($b) - mb_strlen($a);
    });
    $str_terms = implode('|', $terms);

    /* server side highlighter */
    $buf = preg_replace_callback('#((?:(?!<[/a-z]).)*)([^>]*>|$)#si',
                        function ($matches) use ($str_terms) {
                            //return preg_replace('/(?<=[\s:\-\>\(\)\.,\/^])('.$str_terms.')(?=[\s:\-\<\(\)\.,\/]|$)/i', '<span class="highlight">$1</span>', $matches[1]).$matches[2];
                            return preg_replace('/(?<!\pL)('.$str_terms.')(?!\pL)/i', '<span class="highlight">$1</span>', $matches[1]).$matches[2];
                        }, $buf);

    return $buf;
}

Thanks to everybody.