regex to match and ?

Question

I found this code posted on SO to change text links into hyperlinks:

function auto_link_text($text)
{ 
   $pattern  = '#\b(([\w-]+://?|www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/)))#';
   $callback = create_function('$matches', '
   $url       = array_shift($matches);
   $url_parts = parse_url($url);

   $text = parse_url($url, PHP_URL_HOST) . parse_url($url, PHP_URL_PATH);
   $text = preg_replace("/^www./", "", $text);

   $last = -(strlen(strrchr($text, "/"))) + 1;
   if ($last < 0) {
       $text = substr($text, 0, $last) . "&hellip;";
   }

   return sprintf(\'<a rel="nowfollow" href="%s">%s</a>\', $url, $text);
  ');

  return preg_replace_callback($pattern, $callback, $text);
}

However, it seems to change them into hyperlinks even if they are already a part of a hyperlink so you end up with something like <a href="<a href (etc). I figure what I could do is check for an already formatted hyperlink and if I don't find one, I can do that function. Or even put the check in the function. So something like:

  function auto_link_text($text)
{
  if preg_match(proper stuff in here){
      return $text;
        }else{
       $pattern  = '#\b(([\w-]+://?|www[.])[^\s()<>]+(?:\([\w\d]+\)|([^[:punct:]\s]|/)))#';
       $callback = create_function('$matches', '
   $url       = array_shift($matches);
   $url_parts = parse_url($url);

   $text = parse_url($url, PHP_URL_HOST) . parse_url($url, PHP_URL_PATH);
   $text = preg_replace("/^www./", "", $text);

   $last = -(strlen(strrchr($text, "/"))) + 1;
   if ($last < 0) {
       $text = substr($text, 0, $last) . "&hellip;";
   }

   return sprintf(\'<a rel="nowfollow" href="%s">%s</a>\', $url, $text);
  ');

  return preg_replace_callback($pattern, $callback, $text);
}
}

Or perhapse the regex in the function should be changed.

possible duplicate of [Automatically convert keywords to links in php](http://stackoverflow.com/questions/9929953/automatically-convert-keywords-to-links-in-php) — Anthony, Apr 06 '12 at 23:09
Check out my [answer](http://stackoverflow.com/questions/9929953/automatically-convert-keywords-to-links-in-php/9932767#9932767). — Anthony, Apr 06 '12 at 23:09
[Possible duplicate](http://stackoverflow.com/questions/1732348/regex-match-open-tags-except-xhtml-self-contained-tags) — c69, Apr 06 '12 at 23:09

score 2 · Accepted Answer · answered Apr 06 '12 at 23:08

2

Add (?<!href=") just after the first # of your regex. This will ensure that it's not already inside a tag.

answered Apr 06 '12 at 23:08

Niet the Dark Absol

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This only checks if it's directly preceded by the href, but it won't check if it's somewhere inside of it or if it's in the text node. And nesting links is a bad idea. This would work if php supported wildcard lookbehinds, but it does not. Lookbehinds must be a pre-defined length. – Anthony Apr 06 '12 at 23:12
Erm... this makes sure the url is NOT preceded by `href="`, which means it is not inside an `href` attribute. You could go more brute-forcey and just have `(?<!=")` to test for `="`. My own code just has `"` because genuine instances of `"` in the input have already been converted to `"`. – Niet the Dark Absol Apr 06 '12 at 23:14
@Kolink I added that and input `google` and it still broke up the link. – qitch Apr 06 '12 at 23:18

regex to match and ?

1 Answers1