Forget app_dev.php In Your Symfony Application

I’m not a big fan of the typical app.php and app_dev.php setup in the Symfony Standard Edition. While it’s not a big deal if the app_dev.php file gets deployed, it shouldn’t be done anyway. It’s too risky and complicates the deploy process a bit.

The alternative: environment variables that default to production mode.

Rather than doing new AppKernel('prod', false) in a single index.php entrypoint, we’ll create a named constructor that fetches a few environment variables. The key here is to default to production mode so a botched deployment doesn’t ever expose debug information.

AppKernel.php

<?php

use Symfony\Component\HttpKernel\Kernel;

class AppKernel extends Kernel
{
    public static function fromEnvironment()
    {
        $env = getenv('APP_ENVIRONMENT') ?: 'prod';
        $debug = filter_var(getenv('APP_DEBUG'), FILTER_VALIDATE_BOOLEAN);

        return new self($env, $debug);
    }
     // ...
}

Now use that named constructor as your main entrypoint — app.php in Symfony standard, though I like to just use index.php. And remove the app_dev.php file.

index.php

<?php

use Symfony\Component\HttpFoundation\Request;

// require autoloader or bootstrap
require __DIR__ . '/../app/autoload.php';

// from the environment!
$app = AppKernel::fromEnvironment();

// just like normal
$request = Request::createFromGlobals();
$response = $app->handle($request);
$response->send();
$app->terminate($request, $response);

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