Page.php

<?php declare(strict_types=1);

abstract class Page {

    protected mysqli $database;

    protected function __construct() {
        error_reporting(E_ALL);

        $this->database = new mysqli("localhost","root", "","nasa");

        // Check connection
        if ($this->database->connect_errno) {
          echo "Failed to connect to MySQL: " . $mysqli -> connect_error;
          exit();
        }

        // set charset to UTF8!!
        if (!$this->database->set_charset("utf8")) {
            throw new Exception($this->_database->error);
        }
    }  
    
    protected function __destruct() {
        /*$this->database->close();*/
    }

    protected function generatePageHeader(string $title = "", string $jsScript = ""):void
    {
        $title = htmlspecialchars($title);
        header("Content-type: text/html; charset=UTF-8");
        
        echo <<<EOT
<!DOCTYPE html>
<html lang="de">
<head>
    <title>$title</title>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1">
EOT;
        if (!empty(trim($jsScript)))
            echo "<script src=\"$jsScript\"></script>";

        echo <<<EOT
    <link rel="stylesheet" style="text/css" href="../styles.css" />
</head>
EOT;
    }

    protected function generatePageFooter():void
    {
        echo <<<EOT
</html>
EOT;
    }

    protected function processReceivedData():void {

    }
}