WordPress CodePen Quick Link Embed - WP Embed Register Handler for CodePen embedded pens in posts from the pen url that is pasted into the wp editor. Using regex to pull the username and pen id slug hash from any CodePen pen link in order to register the embed handler in WordPress. http://codex.wordpress.org/Function_Reference/wp_embed_register_…

wordpress-codepen-quick-link-embed.php

/**
*
* Creates an Embed Handler for CodePen Embeds
* Tested on WP 3.7.1
*
*/
wp_embed_register_handler( 'codepen', '/http?:\/\/codepen\.io\/([a-z0-9]+)\/pen\/([a-z0-9]+)/i', 'wp_embed_handler_codepen');
function wp_embed_handler_codepen( $matches, $attr, $url, $rawattr ) {
	$embed = sprintf(
		'<p data-height="268" data-theme-id="0" data-user="%1$s" data-slug-hash="%2$s" data-default-tab="result" class="codepen"><a href="http://codepen.io/%1$s/pen/%2$s">A Pen by %1$s</a> (<a href="http://codepen.io/%1$s">@%1$s</a>) on <a href="http://codepen.io">CodePen</a></p>
		<script async src="//codepen.io/assets/embed/ei.js"></script>',
			esc_attr($matches[1]),
			esc_attr($matches[2])
			);

	return apply_filters( 'embed_codepen', $embed, $matches, $attr, $url, $rawattr );
}