PHP

A popular specific-purpose scripting language that is especially suited to web development.

When to Use

Modern Full-Stack Web Development: Powering high-velocity Laravel and Symfony web backends with rich ecosystem tooling.
Enterprise CMS Platforms: Building and extending WordPress, Drupal, and headless CMS architectures.
High-Performance Asynchronous APIs (FrankenPHP / Swoole): Running persistent in-memory PHP workers serving thousands of requests per second.
Rapid CRUD & API Engineering: Building robust APIs quickly with PHP 8.3/8.4 typed properties, attributes, and match expressions.

Quick Start

<?php
$name = "World";
echo "Hello, $name!";

$colors = ["red", "green", "blue"];
foreach ($colors as $color) {
    echo $color . "<br>";
}
?>

Core Concepts

Modern Strict Typing & Constructor Promotion (PHP 8.2+)

Enforces strict scalar types, readonly classes, and promoted constructor properties:

<?php
declare(strict_types=1);

namespace App\Domain;

final readonly class Order
{
    public function __construct(
        public string $id,
        public float $amount,
        public OrderStatus $status = OrderStatus::Pending,
        public \DateTimeImmutable $createdAt = new \DateTimeImmutable()
    ) {}
}

enum OrderStatus: string
{
    case Pending = 'PENDING';
    case Paid = 'PAID';
    case Shipped = 'SHIPPED';
}

Expressive `match` Expressions & First-Class Callables

Replaces verbose switch statements with strict type comparison and returned values:

function getDiscountPercentage(OrderStatus $status): float
{
    return match ($status) {
        OrderStatus::Pending => 0.0,
        OrderStatus::Paid    => 0.05,
        OrderStatus::Shipped => 0.10,
    };
}

Modern Fiber-Based Concurrency & Persistent Runtimes

Runs concurrent fibers and persistent memory workers with FrankenPHP:

$fiber = new Fiber(function (): void {
    $value = Fiber::suspend('paused');
    echo "Resumed with: $value
";
});

$result = $fiber->start();
$fiber->resume('active');

Common Patterns

Constructor Promotion and Readonly Properties

Problem: Verbose boilerplate required to declare, type, and assign class properties.

Solution: Use PHP 8 constructor property promotion with readonly:

<?php
declare(strict_types=1);

readonly class UserProfile
{
    public function __construct(
        public int $id,
        public string $name,
        public string $email,
        public array $roles = ['user']
    ) {}
}

$user = new UserProfile(1, 'Jane', 'jane@example.com');
echo $user->name;

Best Practices

Do:

Always Add declare(strict_types=1);: Enforce strict scalar type checking at the top of every single PHP file.
Use PHPStan or Psalm at Level 8+: Integrate static analysis in CI to eliminate type bugs and undefined method calls.
Deploy with FrankenPHP or Octane: Maximize throughput by serving applications via persistent workers in production.
Use DateTimeImmutable: Prevent accidental time-mutation bugs by replacing mutable DateTime with DateTimeImmutable.

Don't:

Use raw superglobals ($_POST, $_GET): Validate incoming parameters via framework Request classes and validation schemas.
Use weak comparison (==): Always use strict equality (===) to avoid unintended type coercion.
Ignore Composer lock files: Always commit composer.lock and run composer install --no-dev --optimize-autoloader in production.

Troubleshooting

| Error | Cause | Solution | | :-------------------------------------------------------- | :------------------------------------------------------ | :-------------------------------------------------------------------------------- | | TypeError: Argument 1 passed must be of the type ... | Strict types enabled and caller passed mismatched type. | Cast argument explicitly or verify caller inputs. | | Fatal error: Allowed memory size of ... bytes exhausted | Script exceeded memory_limit loading large dataset. | Use generators (yield) or increase memory_limit in php.ini. | | Class '...' not found | Autoloader not included or Composer autoloader stale. | Add require __DIR__ . '/vendor/autoload.php'; and run composer dump-autoload. |