Filtering WordPress oEmbed provider list

Question

How would I filter the WordPress oEmbed provider list? My aim is to allow just Twitter and Youtube.

EDIT: Could I do something like this?

function filter_oembed_provider_list( $array ) {
    $array = array( 'http://youtu.be/*' => array( 'http://www.youtube.com/oembed',                     false ) );
    return $array;
}
add_filter( 'oembed_providers', 'filter_oembed_provider_list' );

But this doesn't seem to work.

Please see the relevant code in class-oembed.php:

apply_filters( 'oembed_providers', array(
        '#https?://(www\.)?youtube\.com/watch.*#i'           => array( 'http://www.youtube.com/oembed',                     true  ),
        'http://youtu.be/*'                                  => array( 'http://www.youtube.com/oembed',                     false ),
        'http://blip.tv/*'                                   => array( 'http://blip.tv/oembed/',                            false ),
        '#https?://(www\.)?vimeo\.com/.*#i'                  => array( 'http://vimeo.com/api/oembed.{format}',              true  ),
        '#https?://(www\.)?dailymotion\.com/.*#i'            => array( 'http://www.dailymotion.com/services/oembed',        true  ),
        'http://dai.ly/*'                                    => array( 'http://www.dailymotion.com/services/oembed',        false ),
        '#https?://(www\.)?flickr\.com/.*#i'                 => array( 'http://www.flickr.com/services/oembed/',            true  ),
        'http://flic.kr/*'                                   => array( 'http://www.flickr.com/services/oembed/',            false ),
        '#https?://(.+\.)?smugmug\.com/.*#i'                 => array( 'http://api.smugmug.com/services/oembed/',           true  ),
        '#https?://(www\.)?hulu\.com/watch/.*#i'             => array( 'http://www.hulu.com/api/oembed.{format}',           true  ),
        '#https?://(www\.)?viddler\.com/.*#i'                => array( 'http://lab.viddler.com/services/oembed/',           true  ),
        'http://qik.com/*'                                   => array( 'http://qik.com/api/oembed.{format}',                false ),
        'http://revision3.com/*'                             => array( 'http://revision3.com/api/oembed/',                  false ),
        'http://i*.photobucket.com/albums/*'                 => array( 'http://photobucket.com/oembed',                     false ),
        'http://gi*.photobucket.com/groups/*'                => array( 'http://photobucket.com/oembed',                     false ),
        '#https?://(www\.)?scribd\.com/.*#i'                 => array( 'http://www.scribd.com/services/oembed',             true  ),
        'http://wordpress.tv/*'                              => array( 'http://wordpress.tv/oembed/',                       false ),
        '#https?://(.+\.)?polldaddy\.com/.*#i'               => array( 'http://polldaddy.com/oembed/',                      true  ),
        '#https?://(www\.)?funnyordie\.com/videos/.*#i'      => array( 'http://www.funnyordie.com/oembed',                  true  ),
        '#https?://(www\.)?twitter\.com/.+?/status(es)?/.*#i'=> array( 'http://api.twitter.com/1/statuses/oembed.{format}', true  ),
        '#https?://(www\.)?soundcloud\.com/.*#i'             => array( 'http://soundcloud.com/oembed',                      true  ),
        '#https?://(www\.)?slideshare\.net/*#'               => array( 'http://www.slideshare.net/api/oembed/2',            true  ),
        '#http://instagr(\.am|am\.com)/p/.*#i'               => array( 'http://api.instagram.com/oembed',                   true  ),
        '#https?://(www\.)?rdio\.com/.*#i'                   => array( 'http://www.rdio.com/api/oembed/',                   true  ),
        '#https?://rd\.io/x/.*#i'                            => array( 'http://www.rdio.com/api/oembed/',                   true  ),
        '#https?://(open|play)\.spotify\.com/.*#i'           => array( 'https://embed.spotify.com/oembed/',                 true  ),
    ) );

Answer 1

There is a built-in function wp_oembed_remove_provider, respectively wp_oembed_add_provider.

EDIT

add to functions.php file

function customize_oembed() {

    //load oembed class
    require_once ABSPATH . DIRECTORY_SEPARATOR . 'wp-includes' . DIRECTORY_SEPARATOR . 'class-oembed.php';

    //get a singleton object
    $oembed = _wp_oembed_get_object();

    /**
     * Forget about those lines
     *
       //empty the providers list
       $oembed->providers = array();

       //add what you want
       wp_oembed_add_provider( 'http://site.com/watchvideo/*', 'http://site.com/oembedprovider' );  
    */

    //use applying a filter
    $providers = array(
        'youtube' => array( 'http://www.youtube.com/oembed', false), 
        'twitter'=> array( 'http://api.twitter.com/1/statuses/oembed.{format}', true  )
    );
    $oembed->providers = apply_filters('oembed_providers', $providers);
}
add_action('init', 'customize_oembed');

EDIT 2

I looked into it, and I found out, that you can use a filter oembed_providers exactly in the same way, as it is used in a constructor of the class. Therefore using additional wordpress functions, which would again try to require the class file and instantiate a singleton object, is useless, when you can do it in one function.

(Despite of the fact, that it works, i still do not get a usage of this filter :-D)

EDIT 3

Finally, I got it working.

It is really similar code to yours, though the argument in the function is basically useless. It only gives you original providers, which you want to override, so you are not using it and you can return an array directly.

Maybe the important thing to remember is, after editing your list, you need to update your posts, since wordpress is saving some data into table *_postmeta under key _oembed_…

function filter_oembed_provider_list( ) {
    return array( 'http://youtu.be/*' => array( 'http://www.youtube.com/oembed', false ) );
}
add_filter( 'oembed_providers', 'filter_oembed_provider_list' );