Source
File: wp-includes/embed.php
function _oembed_rest_pre_serve_request( $served, $result, $request, $server ) {
$params = $request->get_params();
if ( '/oembed/1.0/embed' !== $request->get_route() || 'GET' !== $request->get_method() ) {
return $served;
}
if ( ! isset( $params['format'] ) || 'xml' !== $params['format'] ) {
return $served;
}
// Embed links inside the request.
$data = $server->response_to_data( $result, false );
if ( ! class_exists( 'SimpleXMLElement' ) ) {
status_header( 501 );
die( get_status_header_desc( 501 ) );
}
$result = _oembed_create_xml( $data );
// Bail if there's no XML.
if ( ! $result ) {
status_header( 501 );
return get_status_header_desc( 501 );
}
if ( ! headers_sent() ) {
$server->send_header( 'Content-Type', 'text/xml; charset=' . get_option( 'blog_charset' ) );
}
echo $result;
return true;
}