regex to detect plain email AND mailto: link emails

Question

My users use a CMS to enter job offers. In these job offers, sometimes the email address is in plain format (please contact job@job.com) or as an html mailto: link (<a href="mailto:job@job.com">jobline</a> and the even more annoying one <a href="mailto:job@job.com">job@job.com</a>).

I would like to build a php function that finds either format and make them spamproof by building an html string that tells humans what to do, and via javascript reconstruct a proper clickable mailto:link for javascript-enabled setups. It's the detection part that i have problem with.

The following works perfect for plain email. How can i adapt it to detect mailto: links too?

$addr_pattern = '/([A-Z0-9._%+-]+)@([A-Z0-9.-]+)\.([A-Z]{2,4})(\((.+?)\))?/i';
preg_match_all($addr_pattern, $content, $addresses);
$the_addrs = $addresses[0];
for ($a = 0; $a < count($the_addrs); $a++) {
     $repaddr[$a] = preg_replace($addr_pattern, '<span title="$5" class="pep-email">$1(' . $opt_val . ')$2.$3</span>', $the_addrs[$a]);
 }
 $cc = str_replace($the_addrs, $repaddr, $content);

PS: this is to improve an existing wordpress plugin: Pixeline's Email protector. Winning answer's author will be dully credited in the plugin code, description and changelog.

Answer 1

It would be better to use the domdocument class to get the actual links as there are so many different possible ways to write them. You can also use it with a regex to scan the entire content to replace the text at the same time.

    // The content
$content = 'The stuff from the page';

// Start the dom object
$dom = new DOMDocument();
$dom->recover = true;
$dom->substituteEntities = true;

// Feed the content to the dom object
$dom->loadHTML($content);

// Check each link
foreach ($dom->getElementsByTagName('a') as $anchor) {
// Get the href
$href = $anchor->getAttribute('href');
// Check if it's a mailto link
if (substr($href, 0, 7) == 'mailto:') {
    # Do something with it
    $href = 'new link href';
}
// Put it back in the link
$anchor->setAttribute('href', $href);
}

// Replace the content with the new content
$content = $dom->saveHTML();

Answer 2

(<a href="mailto:|)([a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4})(">.+?</a>|)

This should match all variations then replace with $2