Krdytkyu

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.

<?php



namespace AppServices;



use AppLine;

use SymfonyComponentHttpFoundationStreamedResponse;

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,

        ];

    }

}

Try to think about this in a more generic way, you basically have:

1. Select data from DB


2. Put that data in a CSV (will you in the future want to use other formats like XLSX, etc? If so, we should abstract this step too, but I wont do this right now)


3. Return that CSV file (doesn't matter to who you're returning)

So we can create a few classes from those steps

1. Any class that can query the DB, your app probably has a bunch of them


2. AbstractWriter - this class is an abstraction/interface to write anywhere, you'll need to implement it for specific formats, like Writer/Csv, Writer/Xlsx, Writer/JSON, etc.


3. AbstractFileReturner - this class is an abstraction/interface to return it to anyone, you'll need to implement it for specific cases, AbstractFileReturner/like Sftp, AbstractFileReturner/HttpResponse, etc.

Any time you need more File formats or Returner, you just implement the AbstractWriter or FileReturner respectively one more time.

Doing all these, you'll be using Single Responsability Principle (each class do only one thing) and Open/Closed (the abstractions/interfaces are closed for modification, but open for extension).