CsvExporter.php

abstract class CsvExporter
{
    protected $repository;

    protected $file;

    protected $writer;

    protected $parameters;

    public function __construct(RepositoryInterface $repository, TransformerInterface $transformer, array $parameters)
    {
        $this->repository = $repository;
        $this->parameters = $parameters;
        $this->file = new SplTempFileObject();

        $this->writer = Writer::createFromFileObject($this->file);
        $this->writer->insertOne($transformer->getHeaders());
        $this->writer->addFormatter([$transformer, 'transform']);
    }
}