MergePDFActivity.php

<?php

namespace App\Workflows\BuildPDF;

use setasign\Fpdi\Fpdi;
use Workflow\Activity;

class MergePDFActivity extends Activity
{
    public function execute($pages)
    {
        $fileName = uniqid() . '.pdf';

        $pdf = new Fpdi();

        foreach ($pages as $page) {
            $pdf->AddPage();
            $pdf->setSourceFile(storage_path($page));
            $pdf->useTemplate($pdf->importPage(1));
        }

        $pdf->Output('F', storage_path($fileName));

        foreach ($pages as $page) {
            unlink(storage_path($page));
        }

        return $fileName;
    }
}