class-mstdn-link-builder.php

<?php
new Mstdn_Link_Builder();

/**
 * Class Name: Mstdn_Link_Builder
 *@author @ottanxyz
 */
class Mstdn_Link_Builder {

	function __construct() {
		wp_embed_register_handler(
			'mstdn_link_builder',
			'/^(https:\\/\\/mstdn\\.jp\\/@([a-zA-Z0-9]+)\\/[0-9]+)$/i',
			array( &$this, 'handler' )
		);
		add_shortcode( 'mstdn', array( &$this, 'display' ) );
	}

	public function handler( $matches, $attr, $url, $rawattr ) {
		$response = wp_remote_get( $url );
		$link = $response['headers']['link'];
		preg_match( '/([0-9]+)\.atom/i' , $link, $code );
		$user = $matches[2];
		return "[mstdn user=\"${user}\" code=\"${code[1]}\"]";
	}

	public function display( $p ) {
		if ( ! isset( $p['code'] ) || ! $p['code'] ) {
			return;
		}
		if ( ! isset( $p['user'] ) || ! $p['user'] ) {
			return;
		}

		echo '<iframe src="https://mstdn.jp/users/' . $p['user'] . '/updates/' . $p['code'] . '/embed" style="width:100%;overflow:hidden" frameborder=0 scrolling="no"></iframe>';
	}
}