//跨域session域名配置,获取当前主机名 
$host_array = explode('.', $_SERVER["HTTP_HOST"]); 
//针对com域名，获取顶级域名 
if (count($host_array) == 3) { 
  define('DOMAIN', $host_array[1] . '.' . $host_array[2]); 
} 
//针对com.cn域名 
elseif (count($host_array) == 4) { 
  define('DOMAIN', $host_array[1] . '.' . $host_array[2]. '.' . $host_array[3]); 
} 
else{ 
  //echo "本系统不支持本地访问，请配置域名";exit; 
} 
define('DOMAIN_HOME', 'www.' . DOMAIN); 
define('DOMAIN_YUN', 'yun.' . DOMAIN); 
define('DOMAIN_API', 'api.' . DOMAIN); 
define('DOMAIN_EMAIL', 'mail.' . DOMAIN); 
define('DOMAIN_IMG', 'img.' . DOMAIN); 

'user' => [ 
      'identityClass' => 'common\models\User', 
      'enableAutoLogin' => true, 
      'identityCookie' => ['name' => '_identity', 'httpOnly' => true, 'domain' => '.' . DOMAIN], 
    ], 
    'session' => [ 
      'cookieParams' => ['domain' => '.' . DOMAIN, 'lifetime' => 0], 
      'timeout' => 3600, 
    ],