note 73435 added to function.strip-tags

I needed a way to allow user comments to contain only hyperlinks as the only allowed HTML tags. This is easy enough to accomplish, but I also needed a way to convert full URLs into hyperlinks, and this complicated things a bit. The functions below are not very elegant, but do the job. Function strip_tags_except() works similarly to the strip_selected_tags() function defined a few times on this page, but instead of allowing the user to specify the tags to strip, she can specify the tags to allow and strip all others. The third parameter, $strip, when TRUE removes "<" and ">" from the string and when FALSE converts them to "&lt;" and "&gt;" respectively. Function url_to_link() simply converts full URLs into an equivalent hyperlink taking into consideration that users may end a URL with a character that's not actually part of the address. When using both, url_to_link() should be called before strip_tags_except(). Here's an example as we are using it on http://www.VideoSift.com: <?php $summary = url_to_link($summary); $summary = strip_tags_except($summary, array('a'), FALSE); ?> Here are the function definitions: <?php function strip_tags_except($text, $allowed_tags, $strip=TRUE) { if (!is_array($allowed_tags)) return $text; if (!count($allowed_tags)) return $text; $open = $strip ? '' : '&lt;'; $close = $strip ? '' : '&gt;'; preg_match_all('!<\s*(/)?\s*([a-zA-Z]+)[^>]*>!', $text, $all_tags); array_shift($all_tags); $slashes = $all_tags[0]; $all_tags = $all_tags[1]; foreach ($all_tags as $i => $tag) { if (in_array($tag, $allowed_tags)) continue; $text = preg_replace('!<(\s*' . $slashes[$i] . '\s*' . $tag . '[^>]*)>!', $open . '$1' . $close, $text); } return $text; } function url_to_link($text) { $text = preg_replace('!(^|([^\'"]\s*))' . '([hf][tps]{2,4}:\/\/[^\s<>"\'()]{4,})!mi', '$2<a href="$3">$3</a>', $text); $text = preg_replace('!<a href="([^"]+)[\.:,\]]">!', '<a href="$1">', $text); $text = preg_replace('!([\.:,\]])</a>!', '</a>$1', $text); return $text; } ?> ---- Server IP: 64.71.164.2 Probable Submitter: 68.5.231.178 ---- Manual Page -- http://www.php.net/manual/en/function.strip-tags.php Edit -- https://master.php.net/note/edit/73435 Del: integrated -- https://master.php.net/note/delete/73435/integrated Del: useless -- https://master.php.net/note/delete/73435/useless Del: bad code -- https://master.php.net/note/delete/73435/bad+code Del: spam -- https://master.php.net/note/delete/73435/spam Del: non-english -- https://master.php.net/note/delete/73435/non-english Del: in docs -- https://master.php.net/note/delete/73435/in+docs Del: other reasons-- https://master.php.net/note/delete/73435 Reject -- https://master.php.net/note/reject/73435 Search -- https://master.php.net/manage/user-notes.php