silverstripe-textextraction/code/extractors/HTMLTextExtractor.php

<?php

/**
 * Text extractor that uses php function strip_tags to get just the text. OK for indexing, not the best for readable text.
 * @author mstephens
 *
 */
class HTMLTextExtractor extends FileTextExtractor
{
    public function isAvailable()
    {
        return true;
    }

    public function supportsExtension($extension)
    {
        return in_array(
            strtolower($extension),
            array("html", "htm", "xhtml")
        );
    }

    public function supportsMime($mime)
    {
        return strtolower($mime) === 'text/html';
    }

    /**
     * Lower priority because its not the most clever HTML extraction. If there is something better, use it
     *
     * @config
     * @var integer
     */
    private static $priority = 10;

    /**
     * Extracts content from regex, by using strip_tags()
     * combined with regular expressions to remove non-content tags like <style> or <script>,
     * as well as adding line breaks after block tags.
     * 
     * @param string $path
     * @return string
     */
    public function getContent($path)
    {
        $content = file_get_contents($path);
        // Yes, yes, regex'ing HTML is evil.
        // Since we don't care about well-formedness or markup here, it does the job.
        $content = preg_replace(
            array(
                // Remove invisible content 
                    '@<head[^>]*?>.*?</head>@siu',
                    '@<style[^>]*?>.*?</style>@siu',
                    '@<script[^>]*?.*?</script>@siu',
                    '@<object[^>]*?.*?</object>@siu',
                    '@<embed[^>]*?.*?</embed>@siu',
                    '@<applet[^>]*?.*?</applet>@siu',
                    '@<noframes[^>]*?.*?</noframes>@siu',
                    '@<noscript[^>]*?.*?</noscript>@siu',
                    '@<noembed[^>]*?.*?</noembed>@siu',
                // Add line breaks before and after blocks 
                    '@</?((address)|(blockquote)|(center)|(del))@iu',
                    '@</?((div)|(h[1-9])|(ins)|(isindex)|(p)|(pre))@iu',
                    '@</?((dir)|(dl)|(dt)|(dd)|(li)|(menu)|(ol)|(ul))@iu',
                    '@</?((table)|(th)|(td)|(caption))@iu',
                    '@</?((form)|(button)|(fieldset)|(legend)|(input))@iu',
                    '@</?((label)|(select)|(optgroup)|(option)|(textarea))@iu',
                    '@</?((frameset)|(frame)|(iframe))@iu',
            ),
            array(
                ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', ' ', "$0", "$0", "$0", "$0", "$0", "$0", "$0", "$0",
            ),
            $content
        );
        return strip_tags($content);
    }
}