Azione per il download di file Magento2

È disponibile un metodo di utilità magento che può aiutarmi a creare un'azione di download forzato del contenuto?

puoi creare l'azione del controller estendendola \Magento\Backend\App\Actionper il back-end o \Magento\Framework\App\Action\Actionper il front- end .
e farlo apparire così:

<?php 
namespace Your\Namespace\Here;

class ClassName extends \Magento\Backend\App\Action 
{
    public function __construct(
        \Magento\Framework\Controller\Result\RawFactory $resultRawFactory,
        \Magento\Framework\App\Response\Http\FileFactory $fileFactory,
        \Magento\Backend\App\Action\Context $context
    ) {
        $this->resultRawFactory      = $resultRawFactory;
        $this->fileFactory           = $fileFactory;
        parent::__construct($context);
    }
    public function execute()
    {
        //do your custom stuff here
        $fileName = 'file name for download here';
        $this->fileFactory->create(
            $fileName,
            null, //content here. it can be null and set later 
            base dir of the file to download here
            'application/octet-stream', //content type here
            content lenght here...can be null
        );
        $resultRaw = $this->resultRawFactory->create();
        $resultRaw->setContents(contents of file here); //set content for download file here
        return $resultRaw;
    }
}

Inoltre è possibile fornire un percorso per un file che si desidera scaricare:

//Send file for download
//@see Magento\Framework\App\Response\Http\FileFactory::create()
return $this->_fileFactory->create(
    //File name you would like to download it by
    $filename,
    [
        'type'  => "filename", //type has to be "filename"
        'value' => "folder/{$filename}", // path will append to the
                                         // base dir
        'rm'    => true, // add this only if you would like the file to be
                         // deleted after being downloaded from server
    ],
    \Magento\Framework\App\Filesystem\DirectoryList::MEDIA
);

Basato sulla risposta che Marius ha dato.

class Download extends \Magento\Framework\App\Action\Action
{
    protected $resultRawFactory;
    protected $fileFactory;

    public function __construct(
        \Magento\Framework\Controller\Result\RawFactory $resultRawFactory,
        \Magento\Framework\App\Response\Http\FileFactory $fileFactory,
        \Magento\Backend\App\Action\Context $context
    ) {
        $this->resultRawFactory      = $resultRawFactory;
        $this->fileFactory           = $fileFactory;
        parent::__construct($context);
    }
    public function execute()
    {
        try{
            $fileName = 'FileName'; // the name of the downloaded resource
            $this->fileFactory->create(
                $fileName,
                [
                    'type' => 'filename',
                    'value' => 'relative/path/to/file/from/basedir'
                ],
                DirectoryList::MEDIA , //basedir
                'application/octet-stream',
                '' // content length will be dynamically calculated
            );
        }catch (\Exception $exception){
            // Add your own failure logic here
            var_dump($exception->getMessage());
            exit;
        }
        $resultRaw = $this->resultRawFactory->create();
        return $resultRaw;
    }
}

Non avere le autorizzazioni corrette (anche se qui è necessaria una lettura i controlli Magento per le autorizzazioni di scrittura) comporterà uno strano errore. "Il sito è inattivo o spostato" o smth in questo modo.

Vale la pena dare un'occhiata alla logica all'interno di $ fileFactory-> create ().