unify database initialization in php file - php

Question

I'm completely new to PHP. I am creating a website.
In several pages, I start my code with :
<?php
$dsn = "mysql:host=localhost;dbname=db;";
$options = [
PDO::ATTR_EMULATE_PREPARES => false,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
];
try {
$pdo = new PDO($dsn,'root','', $options);
} catch (Exception $e) {
die('Erreur : ' . $e->getMessage());
}
//rest of the php + html code here
I would like to unify this code in one php file and call $pdo in every page. But I want to do it in a safe way. Can anyone help.

Answer 1

Better using a singleton for this. This way you avoid opening multiple database connections:
<?php
class Database
{
public static $pdo;
public static function getPDO()
{
if (null === self::$pdo) {
$dsn = "mysql:host=localhost;dbname=db;";
$options = [
PDO::ATTR_EMULATE_PREPARES => false,
PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
];
try {
self::$pdo = new PDO($dsn,'root','', $options);
} catch (Exception $e) {
die('Erreur : ' . $e->getMessage());
}
}
return self::$pdo;
}
//protected constructor
protected function __construct()
{
}
}
Then use
require_once('path/to/database.php'); //the file with Database class
$pdo = Database::getPDO();
Of course, you need to include this file/class in every page.
Also, isn't a good practice to hardcode your database credentials. Better load from some .env, getenv() or .ini file.

Answer 2

Save your connection code in a file. Let's call it db_connect.php. Then, using the proper path add the following to each file needing a database connection:
include('path/to/db_connect.php');
You may also use include_once(), require() or require_once() depending on what your needs are.