Double Quotes not matching in (Cake)PHP Regex

I have a regular expression that should be matching some string of the form: src="/blkjad.dafsdf">. It looks like this: (src|href)(\s*)?=(\s*)?(\"|\')/([^/].*?)\4.

While this works fine on one site I'm running, it fails consistently on another, built in Cake. Here's another failing Regex => '/(")/' which should be matching any double quotation in the line.

I'm at a loss right now. One of the senior developers where I work just took a look at it and basically shook his head. Unfortunately, I'm not that proficient with Cake, and I can't seem to find any similar problems online. Any ideas?

edit: For the record, the failing regex uses preg_match_all, while the other (identical/ working regex) uses preg_replace. Here is some relevant code.

$regex['php'] = '/(src|href)(\s*)?=(\s*)?(\"|\')\/([^\/].*?)\4/';

$php = htmlspecialchars(file_get_contents(sprintf('/home/x/x/x/x/x/%s.%s', $string,    $extension)));                                                  echo $php;

 if (preg_match_all($regex['php'], $php, $out)){
    echo sizeof($out);
    echo nl2br(print_r($out, true));
 } else {
    echo 'Doesn\开发者_JAVA技巧't work';
 }

I think the problem comes from the htmlspecialchars() call.

As stated in the PHP documentation

The translations performed are:

• '&' (ampersand) becomes '&'
• '"' (double quote) becomes '"'
• when ENT_NOQUOTES is not set. "'" (single quote) becomes ''' only
• when ENT_QUOTES is set. '<' (less than) becomes '<' '>' (greater than) becomes '>'