Configuring PHP Applications (code to accompany https://youtu.be/L5E2HSHrDjw)

.env.example

DATABASE_HOSTNAME=localhost
DATABASE_USERNAME=db_username
DATABASE_PASSWORD=db_password
DATABASE_NAME=db_name

.gitignore

.env

config.ini

[database]
hostname = localhost
username = db_username
password = db_password
database = db_name

config.json

{
    "database": {
        "hostname": "localhost",
        "username": "db_username",
        "password": "db_password",
        "database": "db_name"
    }
}

config.php

<?php

define("DATABASE_HOSTNAME", "localhost");
define("DATABASE_USERNAME", "db_username");
define("DATABASE_PASSWORD", "db_password");
define("DATABASE_NAME", "db_name");

$config = [
    "database" => [
        "hostname" => "localhost",
        "username" => "db_username",
        "password" => "db_password",
        "database" => "db_name"
    ]
];

config.yaml

database:
    hostname: localhost
    username: db_username
    password: db_password
    database: db_name

index.php

<?php

// Hardcoded values
/*
$hostname = "localhost";
$username = "db_username";
$password = "db_password";
$database = "db_name";

$mysqli = new mysqli($hostname,
                     $username,
                     $password,
                     $database);
*/

// Settings defined in PHP - constants and an array
/*
require __DIR__ . "/config.php";

$mysqli = new mysqli(DATABASE_HOSTNAME,
                     DATABASE_USERNAME,
                     DATABASE_PASSWORD,
                     DATABASE_NAME);

$mysqli = new mysqli($config["database"]["hostname"],
                     $config["database"]["username"],
                     $config["database"]["password"],
                     $config["database"]["database"]);
*/

// INI file
// $config = parse_ini_file(__DIR__ . "/config.ini", true);

// .env
require __DIR__ . "/vendor/autoload.php";

$dotenv = Dotenv\Dotenv::createImmutable(__DIR__);
$dotenv->load();

$mysqli = new mysqli(getenv("DATABASE_HOSTNAME"),
                     getenv("DATABASE_USERNAME"),
                     getenv("DATABASE_PASSWORD"),
                     getenv("DATABASE_NAME"));

$mysqli = new mysqli($_ENV["DATABASE_HOSTNAME"],
                     $_ENV["DATABASE_USERNAME"],
                     $_ENV["DATABASE_PASSWORD"],
                     $_ENV["DATABASE_NAME"]);