eZ Platform supports multiple binary file handling mechanisms by means of an IOHandler interface. This feature is used by the BinaryFile, Media and Image Field Types.

Native IO handler 

The IO API is organized around two types of handlers:

• eZ\Publish\IO\IOMetadataHandler: Stores & reads metadata (validity, size, etc.)
• eZ\Publish\IO\IOBinarydataHandler: Stores & reads binarydata (actual contents)

The IOService uses both.

Configuration

IO handling can now be configured using semantic configuration. Assigning the IO handlers to ezplatform itself is configurable per siteaccess. This is the default configuration:

ezpublish:
    system:
        default:
            io:
                metadata_handler: default
                binarydata_handler: default

metadata and binarydata handlers are configured in the ez_io extension. This is what the configuration looks like for the default handlers. It declares a metadata handler and a binarydata handler, both labelled 'default'. Both handlers are of type 'flysystem', and use the same flysystem adapter, labelled 'default' as well.

ez_io:
    metadata_handlers:
        default:
            flysystem:
                adapter: default
    binarydata_handlers:
        default:
            flysystem:
                adapter: default

The 'default' flysystem adapter's directory is based on your site settings, and will automatically be set to %ezpublish_legacy.root_dir%/$var_dir$/$storage_dir$ (example: /path/to/ezpublish_legacy/var/ezdemo_site/storage).

The native Flysystem handler.

league/flysystem (along with FlysystemBundle) is an abstract file handling library.

It is used as the default way to read & write content binary files in eZ Platform. It can use the local filesystem (our default configuration), but is also able to read/write to sftp, zip or cloud filesystems (dropbox, rackspace, aws-s3).

Handler options

Adapter

The adapter is the 'driver' used by flysystem to read/write files. Adapters can be declared using oneup_flysystem as follows:

oneup_flysystem:
    adapters:
        default:
            local:
                directory: "/path/to/directory"

The way to configure other adapters can be found on the bundle's online documentation. Note that we do not use the Filesystem configuration described in this documentation, only the adapters.