How to Enable WordPress Embeds on Custom Fields

Starting in Version 2.9 WordPress added a super cool feature that lets you embed videos, images and other media by simply adding the source url in the post. So for example you could at the url “https://www.youtube.com/watch?v=PaUFSW3bxF8″ and the video would be automatically added to your post. WordPress currently support auto-embeds from these sources:

• YouTube (only public videos and playlists – “unlisted” and “private” videos will not embed)
• Vimeo
• DailyMotion
• blip.tv
• Flickr (both videos and images)
• Viddler
• Hulu
• Qik
• Revision3
• Scribd
• Photobucket
• PollDaddy
• WordPress.tv (only VideoPress-type videos for the time being)
• SmugMug (WordPress 3.0+)
• FunnyOrDie.com (WordPress 3.0+)
• Twitter (WordPress 3.4+)

You can add more sources programmatically or with a plugin called Embedly.

I wanted to this feature to my Coming Soon plugin but it was not obvious on how to do so. I started hunting down the function that enabled this functionality on the post by searching for all the filters that ran on the template tag “the_content”. I found that on line 1056 in the file /wp-includes/media.php the following code was called:

 
// Attempts to embed all URLs in a post
if ( get_option('embed_autourls') )
    add_filter( 'the_content', array(&$this, 'autoembed'), 8 );

The method autoembed is part of a class called WP_Embed which is defined as “API for easily embedding rich media such as videos and images into content.”

So this was the function I need to pass my custom field content into to get the auto embed urls. I discover this was class was in the $GLOBALS array. so now all I had to do was call the method. Here’s the code.

 
if(isset($GLOBALS['wp_embed']))
    $content = $GLOBALS['wp_embed']->autoembed($content);

This would run your content through the oEmbed process of getting the html for the media urls.

If anyone knows of a better way to do this please let me know in the comments.