PHPOffice/PhpSpreadsheet

$contenido="<?php
require ('../../../vendor/autoload.php');

use PhpOffice\PhpSpreadsheet\Helper\Sample;
use PhpOffice\PhpSpreadsheet\IOFactory;
use PhpOffice\PhpSpreadsheet\Spreadsheet;".'

require_once "../../../vendor/phpoffice/phpSpreadsheet/src/Bootstrap.php";

$helper = new Sample();
if ($helper->isCli()) {
$helper->log("This example should only be run from a Web Browser" . PHP_EOL);

return;

}
// Create new Spreadsheet object
$spreadsheet = new Spreadsheet();

// Set document properties
$spreadsheet->getProperties()->setCreator("Maarten Balliauw")
->setLastModifiedBy("Maarten Balliauw")
->setTitle("Office 2007 XLSX Test Document")
->setSubject("Office 2007 XLSX Test Document")
->setDescription("Test document for Office 2007 XLSX, generated using PHP classes.")
->setKeywords("office 2007 openxml php")
->setCategory("Test result file");

// Add some data
$spreadsheet->setActiveSheetIndex(0)
->setCellValue("A1", "Hello")
->setCellValue("B2", "world!")
->setCellValue("C1", "Hello")
->setCellValue("D2", "world!");

// Miscellaneous glyphs, UTF-8
$spreadsheet->setActiveSheetIndex(0)
->setCellValue("A4", "Miscellaneous glyphs")
->setCellValue("A5", "éàèùâêîôûëïüÿäöüç");

// Rename worksheet
$spreadsheet->getActiveSheet()->setTitle("Simple");

// Set active sheet index to the first sheet, so Excel opens this as the first sheet
$spreadsheet->setActiveSheetIndex(0);

// Redirect output to a client’s web browser (Xlsx)
header("Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");'.'
header("Content-Disposition: attachment; filename=' . "01simple.xlsx".'");
header("Cache-Control: max-age=0");
// If you are serving to IE 9, then the following may be needed
header("Cache-Control: max-age=1");

// If you are serving to IE over SSL, then the following may be needed
header("Expires: Mon, 26 Jul 1997 05:00:00 GMT"); // Date in the past
header("Last-Modified: " . gmdate("D, d M Y H:i:s") . " GMT"); // always modified
header("Cache-Control: cache, must-revalidate"); // HTTP/1.1
header("Pragma: public"); // HTTP/1.0

$writer = IOFactory::createWriter($spreadsheet, "Xlsx");
$writer->save("php://output");

$spreadsheet->disconnectWorksheets();
unset($spreadsheet);?>';

$file = fopen("prueba2.php", "a");
fwrite($file, $contenido);
fclose($file);
header ("Location: prueba2.php");