Authorization

Quick Introduction

Authorization is a single PHP idea you'll use in almost every backend project.

In this lesson you learn only authorization — not five topics at once. By the end you can write a small working example and explain it in an interview.

We connect each lesson to our course projects: Login System, Blog CMS, REST API, Inventory, Employee Management, and E-Commerce Backend.

Business Problem

You're building the Login System. After a user signs in, you need authorization working correctly before storing data or showing a dashboard.

Without understanding Authorization, the team ships bugs: wrong totals, broken sessions, or type errors that only appear in production. This lesson fixes that with one clear pattern you can copy into your project today.

Core Concept

• Authorization is one focused idea — learn it before mixing with other PHP topics.
• Use it in PHP 8.3+ with declare(strict_types=1); at the top of every file.
• Our course project (Login System) uses authorization in real handlers.
• Run small scripts with php file.php after each change — don't just read.
• Interviewers ask for a one-minute explanation plus a tiny code sample.

sequenceDiagram
  Client->>Nginx: HTTP Request
  Nginx->>PHP-FPM: FastCGI
  PHP-FPM->>App: Route Handler
  App->>Session: Read/Write Session
  App-->>Client: HTML / Redirect

Syntax

Core syntax for Authorization. Every keyword below appears in production PHP — Laravel and Symfony use the same primitives under the hood.

declare(strict_types=1);

Keywords: declare · strict_types · namespace

Step-by-Step Example

Run this script locally. Change one value, run again, and watch what changes.

<?php
declare(strict_types=1);

enum Role: string { case Admin = 'admin'; case Editor = 'editor'; case Viewer = 'viewer'; }

final readonly class User {
    public function __construct(public int $id, public Role $role) {}
}

function can(User $user, string $permission): bool {
    return match ($permission) {
        'posts.delete' => $user->role === Role::Admin,
        'posts.edit'   => in_array($user->role, [Role::Admin, Role::Editor], true),
        'posts.view'   => true,
        default        => false,
    };
}

$user = new User(1, Role::Editor);
echo can($user, 'posts.delete') ? 'allowed' : 'denied';

Line by line

1. — part of the authorization example; run the file to see the result.
2. declare(strict_types=1); — turns on strict type checking for this file.
3. enum Role: string { case Admin = 'admin'; case Editor = 'editor'; case Viewer = 'viewer'; } — part of the authorization example; run the file to see the result.
4. final readonly class User { — part of the authorization example; run the file to see the result.
5. public function __construct(public int $id, public Role $role) {} — part of the authorization example; run the file to see the result.

User #42 (user@example.com) balance $19.99

Real-World Example

In the Login System, authorization appears in a single request handler — not spread across ten files. Keep the example small, test it with php, then paste the pattern into your project branch.

<?php
declare(strict_types=1);

// TODO: Authorization exercise for Login System