Filesystem Config

This feature is available in Contao 4.13 and later.

The new filesystem capabilities are currently considered experimental and therefore not covered by Contao’s BC promise. Classes marked with @experimental should be considered internal for now. Although not likely, there could also be some behavioral changes, so be prepared.

Convenience configuration

The filesystem consist of many components:

  • several storage adapters (League\Flysystem\FilesystemAdapter),
  • a Contao\CoreBundle\Filesystem\MountManager, where adapters are mounted,
  • one or more DBAFS services (Contao\CoreBundle\Filesystem\Dbafs\DbafsInterface),
  • a Contao\CoreBundle\Filesystem\Dbafs\DbafsManager, where DBAFS services are registered,
  • and finally some virtual filesystems (Contao\CoreBundle\Filesystem\VirtualFilesystemInterface) as consumer endpoints.

In case of our DBAFS implementation (Contao\CoreBundle\Filesystem\Dbafs\Dbafs), each instance also needs an individual hash generator (Contao\CoreBundle\Filesystem\Dbafs\Hashing\HashGeneratorInterface).

We need this level of detail to support all use cases, but wanted to offer a convenient way to add and adjust the setup in your extensions and applications. That’s why we added a FilesystemConfiguration class, that gets constructed with a ContainerBuilder instance and provides convenience methods that orchestrate everything you need in the background.

In a Bundle

To use the FilesystemConfiguration in your bundle, implement the ConfigureFilesystemInterface in your extension class:

// src/DependencyInjection/MyFooBundleExtension.php
namespace My\FooBundle\DependencyInjection;

use Contao\CoreBundle\DependencyInjection\Filesystem\ConfigureFilesystemInterface;
use Contao\CoreBundle\DependencyInjection\Filesystem\FilesystemConfiguration;
use Symfony\Component\HttpKernel\DependencyInjection\Extension;

class MyFooBundleExtension extends Extension implements ConfigureFilesystemInterface 
    public function configureFilesystem(FilesystemConfiguration $config): void
        // Configure the filesystem here
    // …

In your Application

In your application in the Contao Managed Edition, you’ll need to adjust the global manager plugin instead by implementing the ConfigPluginInterface and creating the FilesystemConfiguration yourself. Because plugins are handled before extensions, we need to register a compiler pass (can be an anonymous class):

// src/ContaoManager/Plugin.php
namespace App\ContaoManager;

use Contao\CoreBundle\DependencyInjection\Filesystem\FilesystemConfiguration;
use Contao\ManagerPlugin\Config\ConfigPluginInterface;
use Symfony\Component\Config\Loader\LoaderInterface;
use Symfony\Component\DependencyInjection\ContainerBuilder;

class Plugin implements ConfigPluginInterface
    public function registerContainerConfiguration(LoaderInterface $loader, array $managerConfig)
        $configureFilesystemPass = new class implements CompilerPassInterface {
            public function process(ContainerBuilder $container)
                $config = new FilesystemConfiguration($container);
                // Configure the filesystem here
        $loader->load(static function (ContainerBuilder $container) use ($configureFilesystemPass) {


addVirtualFilesystem Add a new virtual filesystem. Setting the $name to ‘foo’ will create a service and additionally enable constructor injection with an argument VirtualFilesystemInterface $fooStorage if autowiring is available. The $prefix defines the directory the instance should be scoped to. Optionally setting $readonly to true will prevent mutations being made to resources and metadata.
mountAdapter Creates a new adapter and mounts it under the given $mountPath in the MountManager. The $adapter and $options can be set analogous to the configuration of the Flysystem Symfony bundle. Alternatively you can pass in an id of an already existing filesystem adapter service. If you do not set a $name, the id/alias for the adapter service will be derived from the mount path.
mountLocalAdapter Use this shortcut method if you want to create a local adapter. Internally this is using mountAdapter but already resolves project root relative paths and parameter placeholders for you.
registerDbafs Registers a custom $dbafs service definition in the DbafsManager under a given $pathPrefix.
addDefaultDbafs Creates a default DBAFS implementation as a service and internally calls registerDbafs on it. We recommend to use this method if the default implementation fits your needs. Set the $tableName and $hashFunction to be used and optionally disable tracking last modified states by setting $useLastModified to false.

When using addVirtualFilesystem and addDefaultDbafs(), the preconfigured Definition is returned. If you want to tweak it (e.g. if you want to adjust the DBAFS defaults), just add methods calls yourself:

// Manually adjust a configuration, if needed
  ->registerMethodCall('setMaxFileSize', [1048576])


Here is how you could make your automatic database backups be stored on a remote server via SFTP. The first two arguments are directly passed to the Flysystem adapter (see Flysystem docs for more information):

// Mount an SFTP adapter to `/backups`.
    ['host' => '', 'port' => 22, 'username' => 'foobar', 'password' => 's3cr3t'],

Currently there are a lot of filesystem operations in Contao that do not use the new filesystem abstraction yet. So you should not expect file operations to be routed to your adapter when remounting /files for instance. The backups from the above example are an exception to this as they are already refactored.