//WordPress 多域名绑定独立配置 robots.txt 文件
//移除 WordPress 默认 robots
add_action('robots_txt', 'Fanly_remove_robots');
function Fanly_remove_robots() {return '';}
//创建自己的 robots
add_action('do_robots', 'Fanly_do_robots');
function Fanly_do_robots() {
	$robots = $_SERVER['SERVER_NAME']?$_SERVER['SERVER_NAME'].'.txt':$_SERVER['HTTP_HOST'].'.txt';//定义 domain.txt 为 robots.txt 文件
	if (is_readable($robots) !== false) {//判断这个文件是否存在或可读
		$content = file_get_contents($robots);//可读则优先显示文件 robots.txt
		echo $content;
	} else { //否者显示以下
		header( 'Content-Type: text/plain; charset=utf-8' );
		$public = get_option( 'blog_public' );
		if ( '0' == $public ) {//判断网站是否开放
			$output = "User-agent: *n";
			$output .= "Disallow: /n";
		} else {//开放则显示以下
			$site_url = parse_url( site_url() );
			$path = ( !empty( $site_url['path'] ) ) ? $site_url['path'] : '';
			$output .= "Disallow: $path/wp-admin/n";
			$output .= "Allow: $path/wp-admin/admin-ajax.phpn";
		}
		echo apply_filters( 'Fanly_robots_txt', $output, $public );
	}
}