PHP Composer dan Autoloading

Definisi

Composer adalah manajer dependency PHP. composer.json menyimpan paket & autoloading (PSR-4 memetakan namespace ke folder). composer dump-autoload membangun classmap agar new App\X otomatis temukan file.

Kapan dipakai

Wajib untuk project modern (Laravel, Symfony, library apa pun). Pakai untuk install paket, lock versi, dan menjalankan script (composer test, composer lint).

Cara kerja

composer.json

json

{
  "require": { "php": ">=8.1", "guzzlehttp/guzzle": "^7.0" },
  "autoload": {
    "psr-4": { "App\\": "src/" }
  },
  "scripts": { "test": "phpunit" }
}

bash

composer install
composer dump-autoload
composer test

Pakai class

php

require 'vendor/autoload.php';
use App\Service\Payment;
new Payment(); // otomatis load src/Service/Payment.php

Struktur alur

Catatan implementasi

• PSR-4: namespace App\ → folder src/; struktur folder harus cocok namespace.
• composer.lock mengunci versi persis — commit ke repo untuk reproducibility.
• composer install (production) vs composer update (dev) — jangan update sembarangan di prod.
• Untuk optimasi, composer dump-autoload -o (classmap) lebih cepat di prod.

Kesalahan umum

• Folder tak cocok namespace: class not found; cek PSR-4 mapping.
• Lupa dump-autoload: class baru tak terload.
• Edit lock manual: bisa rusak; pakai composer update.
• require di tiap file: cukup sekali vendor/autoload.php.

Referensi terkait

• PHP OOP, Namespace, Autoloading, Traits, Visibility
• Laravel Service Container, DI, Facades, Providers
• Go Modules, Packages, Workspaces, Dependency Management