WP_oEmbed_Controller::get_proxy_item( WP_REST_Request $request )

	public function get_proxy_item( $request ) {
		$args = $request->get_params();

		// Serve oEmbed data from cache if set.
		unset( $args['_wpnonce'] );
		$cache_key = 'oembed_' . md5( serialize( $args ) );
		$data = get_transient( $cache_key );
		if ( ! empty( $data ) ) {
			return $data;
		}

		$url = $request['url'];
		unset( $args['url'] );

		// Copy maxwidth/maxheight to width/height since WP_oEmbed::fetch() uses these arg names.
		if ( isset( $args['maxwidth'] ) ) {
			$args['width'] = $args['maxwidth'];
		}
		if ( isset( $args['maxheight'] ) ) {
			$args['height'] = $args['maxheight'];
		}

		$data = _wp_oembed_get_object()->get_data( $url, $args );

		if ( false === $data ) {
			return new WP_Error( 'oembed_invalid_url', get_status_header_desc( 404 ), array( 'status' => 404 ) );
		}

		/**
		 * Filters the oEmbed TTL value (time to live).
		 *
		 * Similar to the {@see 'oembed_ttl'} filter, but for the REST API
		 * oEmbed proxy endpoint.
		 *
		 * @since WP-4.8.0
		 *
		 * @param int    $time    Time to live (in seconds).
		 * @param string $url     The attempted embed URL.
		 * @param array  $args    An array of embed request arguments.
		 */
		$ttl = apply_filters( 'rest_oembed_ttl', DAY_IN_SECONDS, $url, $args );

		set_transient( $cache_key, $data, $ttl );

		return $data;
	}