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Symfony support

  1. Project directory
  2. Cache

Project directory

Symfony 5.1+ defines the "project dir" as the directory where the composer.json file is. Because box deletes it during PHAR compilation, you need to redefine it in your Kernel. It is usually located in src/Kernel.php and can be defined as follow:


class Kernel extends BaseKernel
    public function getProjectDir()
        return __DIR__.'/../';


What makes Symfony a bit special for shipping it into a PHAR is its compilation step. Indeed the Symfony container can be dumped depending on multiple parameters such the application environment, whether it is in debug mode or not and if the cache is fresh.

A PHAR however is a readonly only environment, which means the container cannot be dumped once inside the PHAR. To prevent the issue, you need to make sure of the following:

  • The cache is warmed up before being shipped within the PHAR
  • The application within the PHAR is running in production mode

To achieve this with the least amount of changes is to:

  • Create the .env.local.php file by running the following command:
$ composer dump-env prod

This will ensure when loading the variables that your application is in production mode.

  • Change the following part of the composer.json file:
"scripts": {
    "auto-scripts": {
        "cache:clear": "symfony-cmd",
        "assets:install %PUBLIC_DIR%": "symfony-cmd"
    "post-install-cmd": [
    "post-update-cmd": [


"scripts": {
    "auto-scripts": {
        "cache:clear": "symfony-cmd"
    "post-autoload-dump": [


  • You skip the installation of assets (which you shouldn't need in the context of a CLI application)
  • Trigger the auto-scripts, which includes the cache warming phase, on the Composer dump-autoload event

This last part takes advantage of Box dumping the autoloader by default.

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