PHP 8.3 Getting Started — Installation, CLI Server, Routing, and OPcache

Modern PHP: What has changed

Forget outdated stereotypes of PHP from 2005. Modern PHP 8.3+ is a fast, strictly-typed, modern language featuring JIT compilation, match expressions, readonly classes, first-class callables, and strong typing.

PHP powers over 75% of the web's content management systems and countless high-performance APIs. It requires no complex build steps or compilation phases—edit a file, save it, and refresh your browser.

Step 1: Installing PHP 8.3 and essential extensions

On modern Debian or Ubuntu systems:

sudo apt update
sudo apt install -y php8.3-cli php8.3-common php8.3-mbstring php8.3-xml php8.3-curl php8.3-opcache

Package breakdown

• php8.3-cli: The Command Line Interface binary (/usr/bin/php), required for terminal scripts and running the built-in development server.
• php8.3-common: Core shared documentation and configuration files.
• php8.3-mbstring: Multibyte string support, essential for international UTF-8 characters and emojis.
• php8.3-xml: XML and DOM document parsing extensions.
• php8.3-curl: High-performance HTTP client library for calling external REST APIs.
• php8.3-opcache: The bytecode caching engine that accelerates production execution by up to 300%.

Verification commands & flag breakdown

# Check installed PHP version and Zend Engine
php -v

# List all compiled and active PHP modules
php -m

# Search for a specific module (e.g. mbstring)
php -m | grep -i mbstring

• -v (version): Prints the exact PHP release, compilation date, and active JIT/Zend engine details.
• -m (modules): Displays an alphabetical list of every loaded extension module.

Step 2: Instant local development with the built-in server

You do not need Apache or Nginx to develop PHP locally on your laptop. PHP includes a lightweight web server built directly into the CLI binary:

php -S 127.0.0.1:8000 -t public/ public/index.php

Command & flag breakdown

• php: The PHP CLI executable.
• -S 127.0.0.1:8000: Launches the built-in development web server listening on localhost port 8000.
• -t public/: Sets the document root directory. Static files (CSS, JS, images) inside this directory are served directly.
• public/index.php: The optional router script. Any HTTP request that does not match an existing static file is routed through this single entry file. This matches the exact production architecture of ww1.ternis.org!

Step 3: Building a Front Controller Micro-Router

In modern web development, all HTTP requests flow through a single entry file (public/index.php). This is the Front Controller pattern:

Create public/index.php:

<?php
declare(strict_types=1);

// 1. Extract the clean URL path without query parameters (?page=2)
$requestUri = $_SERVER['REQUEST_URI'] ?? '/';
$path = parse_url($requestUri, PHP_URL_PATH);

// 2. Simple route matching
if ($path === '/') {
    echo '<h1>Welcome to ternis.org!</h1>';
} elseif (preg_match('#^/hello/(?P<name>[a-zA-Z0-9_-]+)$#', $path, $matches)) {
    // Sanitize user input before outputting to prevent Cross-Site Scripting (XSS)
    $name = htmlspecialchars($matches['name'], ENT_QUOTES, 'UTF-8');
    echo "<h1>Hello, {$name}!</h1>";
} else {
    // Return standard HTTP 404 header
    http_response_code(404);
    echo '<h1>404 Not Found</h1>';
}

Security rule: Always escape HTML output

Step 4: Turbocharging performance with OPcache

In traditional interpreted execution, PHP reads .php files from disk, parses syntax, and compiles them into machine bytecode on every single HTTP request.

OPcache eliminates this overhead completely:

1. When a script runs for the first time, OPcache compiles it into opcode and caches the compiled result directly in server RAM.
2. Subsequent requests execute pre-compiled opcode straight from memory without touching the disk.

Verify OPcache is active in your terminal:

php -i | grep -i "opcache.enable"