05 Databáza z PHP: prihlasovacie údaje, config.php, Composer05 Database from PHP: credentials, config.php, Composer

On sigma you have your own MariaDB database (its name = your database login name_surname). PHP connects to it through PDO (PHP Data Objects). This guide covers keeping the password out of Git, connecting from PHP, and adding libraries with Composer.

You always test on sigma. The database exists only there, and Kubeflow cannot see it directly. Since every save goes to sigma by itself, debugging is as comfortable as if the database were next to you.

The database password must never reach GitHub, not even a private repository. Every project with a database has three files:

If the teacher's assignment has no .gitignore, create it in the root of the assignment folder:

config.php
vendor/
.vscode/

config.example.php:

<?php
return [
    'host'     => 'localhost',
    'dbname'   => 'name_surname',
    'user'     => 'name_surname',
    'password' => 'FILL_IN',
];

config.php: copy config.example.php (right click, Copy, right click, Paste, rename) and fill in your details and the password from the lab. Saving puts it on sigma, never into Git.

db.php (in the root of the assignment):

<?php
$cfg = require __DIR__ . '/config.php';
$pdo = new PDO(
    "mysql:host={$cfg['host']};dbname={$cfg['dbname']};charset=utf8mb4",
    $cfg['user'],
    $cfg['password'],
    [PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION]
);

In every script then require 'db.php'; and use $pdo. Test, test.php:

<?php
ini_set('display_errors', '1');
error_reporting(E_ALL);
require 'db.php';
$rows = $pdo->query('SHOW TABLES')->fetchAll();
echo 'Connected, tables: ' . count($rows);

Open https://sigma.tuke.sk/student/name.surname/it/cv01/test.php. If you see "Connected", it works. If you see "Access denied", check the login and password in config.php.

You look at and edit data and tables in Adminer (guide 03 part 4).

Composer manages PHP libraries (Twig, PHPUnit…). The file composer.json says what the project needs; composer.lock the exact versions; the vendor/ folder holds the downloaded libraries and does not belong in Git (it is in .gitignore).

You run Composer in Kubeflow, in the terminal, in the assignment folder (here with the Twig library as an example):

cd ~/web/it/cv01
composer init --no-interaction
composer config platform.php 8.1.2
composer require twig/twig

platform.php 8.1.2 makes Composer pick library versions that run on sigma (PHP 8.1), even though Kubeflow has 8.3.

Then right click the vendor folder in Explorer, Upload Folder. The vendor folder was created by a command, not by saving, so it has to be uploaded by hand. The same after every further composer require.

In the code: require __DIR__ . '/vendor/autoload.php'; and the libraries are available.

If you clone an assignment with libraries afresh (a new notebook, another computer), vendor is not in it. You create it with composer install (downloads exactly the versions from composer.lock) and upload it with Upload Folder.

• config.php is not in the repository (check on GitHub).
• vendor/ is not in the repository.
• config.example.php, composer.json, composer.lock (if you use Composer) are in the repository.
• On sigma: the page opens and connects to the database.