Using Laravel, I need to export some value from the DB in a CSV and then upload the CSV in a sftp or return it in a Response.

I'm trying to be SOLID but with this scenario, I'm not sure how to proceed. As I understand I should have one class that handle the CSV, one that handle the sFTP, one for the Response, and one to handle the logic of the model (the mapping in my case). But I don't understand how I can separate them.

Later one, I will have more Model to export.

Using Laravel, I need to export some value from the DB in a CSV and then upload the CSV via sFTP or return it in a Response.

I'm trying to be use S.O.L.I.D. principles but with this scenario, I'm not sure how to proceed. As I understand I should have one class that handles the CSV, one that handles the sFTP, one for the Response, and one to handle the logic of the model (the mapping in my case). But I don't understand how I can separate them.

Later one, I will have more Model data to export.

<?php

namespace App\Services;

use App\Line;
use Symfony\Component\HttpFoundation\StreamedResponse;
use Storage;

class LinesCsv
{
    const AUTO = '<AUTO>';
    const DOCUMENT_TYPE = 20;
    const DELIMITER = ';';

    public function exportCSVFileToSftp($filename = 'export.csv')
    {
        $handle = fopen('php://temp', 'w');
        $handle = $this->buildCsv($handle);
        return Storage::disk('sftp')->put($filename, $handle);
    }

    public function exportCSVFileToResponse($filename = 'export.csv')
    {
        return new StreamedResponse(function () use ($filename) {
            $handle = fopen('php://output', 'w');
            $handle = $this->buildCsv($handle);
            fclose($handle);
        }, 200, [
            'Content-Type'        => 'text/csv',
            'Content-Disposition' => 'attachment; filename="' . $filename . '"',
        ]);
    }


    public function buildCsv($handle, $header = false)
    {
        if ($header) {
            fputcsv(
                $handle,
                array_keys($this->lineMapping(Line::first())),
                self::DELIMITER
            );
        }

        Line::with(['invoice', 'invoice.customer', 'item'])
            ->whereHas('invoice', function ($query) {
                $query->where('is_exportable', 1);
            })
            ->chunk(200, function ($lines) use ($handle) {
                foreach ($lines as $line) {
                    fputcsv(
                        $handle,
                        $this->lineMapping($line),
                        self::DELIMITER
                    );
                }
            });

        return $handle;
    }

    protected function lineMapping(Line $line)
    {
        return [
            'Invoice number'            => $line->invoice->id ?? "<NEW>",
            'Document type'             => self::DOCUMENT_TYPE,
            'Date'                      => $line->invoice->date,
        ];
    }
}

<?php

namespace App\Services;

use App\Line;
use Symfony\Component\HttpFoundation\StreamedResponse;
use Storage;

class LinesCsv
{
    const DOCUMENT_TYPE = 20;
    const DELIMITER = ';';

    public function exportCSVFileToSftp($filename = 'export.csv')
    {
        $handle = fopen('php://temp', 'w');
        $handle = $this->buildCsv($handle);
        return Storage::disk('sftp')->put($filename, $handle);
    }

    public function exportCSVFileToResponse($filename = 'export.csv')
    {
        return new StreamedResponse(function () use ($filename) {
            $handle = fopen('php://output', 'w');
            $handle = $this->buildCsv($handle);
            fclose($handle);
        }, 200, [
            'Content-Type'        => 'text/csv',
            'Content-Disposition' => 'attachment; filename="' . $filename . '"',
        ]);
    }


    public function buildCsv($handle, $header = false)
    {
        if ($header) {
            fputcsv(
                $handle,
                array_keys($this->lineMapping(Line::first())),
                self::DELIMITER
            );
        }

        Line::with(['invoice', 'invoice.customer', 'item'])
            ->whereHas('invoice', function ($query) {
                $query->where('is_exportable', 1);
            })
            ->chunk(200, function ($lines) use ($handle) {
                foreach ($lines as $line) {
                    fputcsv(
                        $handle,
                        $this->lineMapping($line),
                        self::DELIMITER
                    );
                }
            });

        return $handle;
    }

    protected function lineMapping(Line $line)
    {
        return [
            'Invoice number'            => $line->invoice->id,
            'Document type'             => self::DOCUMENT_TYPE,
            'Date'                      => $line->invoice->date,
        ];
    }
}