Chapter 1: Environment Setup

1. Installing PHP 8.4

PHP 8.4 is the latest stable version and supports all major operating systems. Choose the installation method for your platform.

macOS (Homebrew)

On macOS, Homebrew is recommended — one command does it all:

# 安装 Homebrew（如果尚未安装）
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

# 安装 PHP 8.4
brew install php

# 确认版本
php -v

Ubuntu / Debian

The default Ubuntu repositories may not include the latest version. It's recommended to add the ppa:ondrej/php repository:

# 添加 PHP PPA 源
sudo add-apt-repository ppa:ondrej/php
sudo apt update

# 安装 PHP 8.4 及常用扩展
sudo apt install php8.4 php8.4-cli php8.4-common php8.4-curl php8.4-mbstring php8.4-xml php8.4-zip

# 确认版本
php -v

Windows

There are several installation options on Windows:

# 方式一：使用 Scoop（推荐）
scoop install php

# 方式二：使用 Chocolatey
choco install php

# 方式三：手动下载
# 从 https://windows.php.net/download/ 下载 VS17 x64 Non Thread Safe 版本
# 解压到 C:\php，将 C:\php 添加到系统 PATH 环境变量

Verify Installation

Regardless of platform, you should see output similar to the following after installation:

$ php -v
PHP 8.4.0 (cli) (built: Nov 21 2024 10:30:05) (NTS)
Copyright (c) The PHP Group
Zend Engine v4.4.0, Copyright (c) Zend Technologies
    with Zend OPcache v8.4.0, Copyright (c), by Zend Technologies

2. php.ini Configuration

php.ini is PHP's core configuration file that controls various runtime behaviors. First, locate it:

# 查看加载的配置文件
php --ini

# 输出示例：
# Configuration File (php.ini) Path: /etc/php/8.4/cli
# Loaded Configuration File: /etc/php/8.4/cli/php.ini
# Scan for additional .ini files in: /etc/php/8.4/cli/conf.d

You can also use php -i | grep "php.ini" for a quick lookup. Below are the most commonly adjusted settings for development:

Example: Setting development environment configuration in php.ini:

; 开发环境推荐配置
display_errors = On
error_reporting = E_ALL
date.timezone = Asia/Shanghai
memory_limit = 256M
upload_max_filesize = 20M
post_max_size = 25M
max_execution_time = 30

3. Built-in Development Server

PHP comes with a lightweight built-in development server — no need to install Apache or Nginx to quickly test your code. It's ideal for development and learning.

First, create a simple index.php file:

<?php
echo "Hello, PHP 8.4!";

Then start the development server in the same directory:

# 启动内置开发服务器
php -S localhost:8000

# 指定文档根目录
php -S localhost:8000 -t public/

# 输出示例：
# [Tue Mar 31 10:00:00 2026] PHP 8.4.0 Development Server started
# Listening on http://localhost:8000
# Press Ctrl-C to quit.

Open http://localhost:8000 in your browser to see the output. You can also use a more complete test page:

<?php
// info.php - 查看完整的 PHP 配置信息
phpinfo();

4. Installing Composer

Composer is PHP's dependency management tool, equivalent to npm for Node.js, pip for Python, and Maven for Java. Nearly all modern PHP projects depend on it.

Installing Composer

# macOS / Linux
curl -sS https://getcomposer.org/installer | php
sudo mv composer.phar /usr/local/bin/composer

# 或通过 Homebrew（macOS）
brew install composer

# Windows（使用 Scoop）
scoop install composer

# 验证安装
composer --version

Initialize a Project

# 在项目目录中初始化
mkdir my-php-project && cd my-php-project
composer init

This will guide you through creating composer.json, which is the project's dependency configuration file:

{
    "name": "yourname/my-php-project",
    "description": "我的 PHP 项目",
    "type": "project",
    "require": {
        "php": ">=8.4"
    },
    "autoload": {
        "psr-4": {
            "App\\": "src/"
        }
    }
}

Install Dependencies

# 安装一个包（例如 HTTP 客户端 Guzzle）
composer require guzzlehttp/guzzle

# 安装开发依赖（例如 PHPUnit 测试框架）
composer require --dev phpunit/phpunit

# 安装 composer.json 中定义的所有依赖
composer install

Using Autoloading

Composer provides an autoloading mechanism — just include one line to use all installed packages:

<?php
// 引入 Composer 自动加载文件（所有项目的入口都需要这一行）
require __DIR__ . '/vendor/autoload.php';

// 现在可以直接使用任何已安装的包
use GuzzleHttp\Client;

$client = new Client();
$response = $client->get('https://api.github.com');
echo $response->getBody();

5. Hello World

Let's write a slightly more complete PHP script to understand the basic syntax elements:

<?php
// hello.php - 第一个 PHP 脚本

// 变量以 $ 开头，无需声明类型
$name = "PHP";
$version = 8.4;
$features = ["类型声明", "枚举", "纤程", "属性钩子"];

// echo 输出内容，双引号支持变量插值
echo "Hello, {$name} {$version}!\n";

// 字符串拼接用 .（不是 +）
echo "当前版本：" . $name . " " . $version . "\n";

// 遍历数组
echo "PHP 8.x 新特性：\n";
foreach ($features as $index => $feature) {
    echo "  " . ($index + 1) . ". {$feature}\n";
}

// 简单函数
function greet(string $who): string {
    return "欢迎学习 {$who}！";
}

echo greet("PHP 8.4") . "\n";

Save the file and run it from the command line:

$ php hello.php
Hello, PHP 8.4!
当前版本：PHP 8.4
PHP 8.x 新特性：
  1. 类型声明
  2. 枚举
  3. 纤程
  4. 属性钩子
欢迎学习 PHP 8.4！

6. VS Code Configuration

VS Code is one of the most popular editors for PHP development. Install the following extensions for a near-IDE development experience:

Quick install in VS Code: Press Ctrl+Shift+X (macOS: Cmd+Shift+X) to open the Extensions panel, then search for the extension name to install.

It's recommended to add a .vscode/settings.json to your project:

{
    "php.validate.executablePath": "/usr/local/bin/php",
    "editor.formatOnSave": true,
    "[php]": {
        "editor.defaultFormatter": "junstyle.php-cs-fixer"
    },
    "intelephense.environment.phpVersion": "8.4.0"
}

7. Chapter Summary