在Yii2中使用$ _SERVER ['SERVER_NAME']检测环境是否正确

if ($_SERVER['SERVER_NAME'] == 'localhost' || $_SERVER['SERVER_NAME'] == '127.0.0.1') 
{
    defined('YII_DEBUG') or define('YII_DEBUG', true);
    defined('YII_ENV') or define('YII_ENV', 'dev');
}

require __DIR__ . '/../../vendor/autoload.php';
require __DIR__ . '/../../vendor/yiisoft/yii2/Yii.php';
require __DIR__ . '/../../common/config/bootstrap.php';
require __DIR__ . '/../config/bootstrap.php';

if(YII_ENV == 'prod')
{
    $config = yii\helpers\ArrayHelper::merge(
        require __DIR__ . '/../../common/config/main.php',
        require __DIR__ . '/../config/main.php'
    );
}
else
{
    $config = yii\helpers\ArrayHelper::merge(
       require __DIR__ . '/../../common/config/main.php',
       require __DIR__ . '/../../common/config/main-local.php',
       require __DIR__ . '/../config/main.php',
       require __DIR__ . '/../config/main-local.php'
   );
}

I am trying to use multiple environments but don't what to change all the time in files so I use if condition in my index.php file and its working but I don't know it is the right way or not.

No, it is not. And this is a potential security issue - $_SERVER['SERVER_NAME'] can be spoofed, so someone may access your remote production server using localhost as a host name. If you're not validating host name at webserver level, then he will see your website in debug mode. From $_SERVER['SERVER_NAME'] docs:

Note: Under Apache 2, you must set UseCanonicalName = On and ServerName. Otherwise, this value reflects the hostname supplied by the client, which can be spoofed. It is not safe to rely on this value in security-dependent contexts.

You should probably keep environment-specific settings/constants in separate file outside of version control. For example in config/environment-local.php. And setup it manually on every instance. You may also use Composer hooks to copy default content of this file - I implemented something like that in my template. Then require this file on the top of your index.php file instead of your condition:

require __DIR__ . '/../config/environmen-local.php';

require __DIR__ . '/../../vendor/autoload.php';
require __DIR__ . '/../../vendor/yiisoft/yii2/Yii.php';
require __DIR__ . '/../../common/config/bootstrap.php';
require __DIR__ . '/../config/bootstrap.php';

// rest of bootstrap