function set_youtube_as_featured_image($post_id) {
// only want to do this if the post has no thumbnail
if(!has_post_thumbnail($post_id)) {
// find the youtube url
$post_array = get_post($post_id, ARRAY_A);
$content = $post_array['post_content'];
$youtube_id = get_youtube_id($content);
// build the thumbnail string
$youtube_thumb_url = 'http://img.youtube.com/vi/' . $youtube_id . '/0.jpg';
// next, download the URL of the youtube image
media_sideload_image($youtube_thumb_url, $post_id, 'Sample youtube image.');
// find the most recent attachment for the given post
$attachments = get_posts(
array(
'post_type' => 'attachment',
'numberposts' => 1,
'order' => 'ASC',
'post_parent' => $post_id
)
);
$attachment = $attachments[0];
// and set it as the post thumbnail
set_post_thumbnail( $post_id, $attachment->ID );
} // end if
} // set_youtube_as_featured_image
add_action('save_post', 'set_youtube_as_featured_image');
function get_youtube_id($content) {
// find the youtube-based URL in the post
$urls = array();
preg_match_all('%(?:youtube(?:-nocookie)?\.com/(?:[^/]+/.+/|(?:v|e(?:mbed)?)/|.*[?&]v=)|youtu\.be/)([^"&?/ ]{11})%i', $content, $urls);
$youtube_url = $urls[0][0];
// next, locate the youtube video id
$youtube_id = '';
if(strlen(trim($youtube_url)) > 0) {
parse_str( parse_url( $youtube_url, PHP_URL_QUERY ) );
$youtube_id = $v;
} // end if
if(empty($youtube_id)){
preg_match_all('#<object[^>]+>.+?http://www.youtube.com/v/([A-Za-z0-9\-_]+).+?</object>#s', $content, $urls);
$youtube_id = $youtube_url = $urls[1][0];
}
return $youtube_id;
} // end get_youtube_id
