laravel code maintenance, use php artisan to use the application under maintenance_PHP tutorial

When the application is under maintenance, we can temporarily close the program. The specific use is to use
php artisan down
artisan is a program in the laravel root directory. When this command is executed When the maintenance is completed, use php artisan up to enable the application
App::down(function()
{
return Response::make("Be right back!", 503);
});

command is: php artisan key:generate
If the key has been set, clear it first. That’s it