Creating a RESTful API with PHP

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RESTful APIs are a widely used approach for building web services. In this guide, you'll learn the basics of developing a RESTful API using PHP, with practical examples to help you understand the process.

1. RESTful API Basics

REST (Representational State Transfer) is an architectural style that uses HTTP for communication. Each action typically corresponds to an HTTP method:

GET – Read data
POST – Add new data
PUT – Update existing data
DELETE – Delete data

2. Building a RESTful API with PHP

2.1. Directory Structure

Use the following structure to organize your API files:

GENEL

/api
    |-- index.php
    |-- config.php
    |-- database.php
    |-- routes.php
    |-- controllers
        |-- UserController.php
    |-- models
        |-- User.php

2.2. Database Setup (Using MySQL)

Create a database and a users table using the SQL below:

SQL

CREATE DATABASE testdb;
USE testdb;

CREATE TABLE users (
    id INT AUTO_INCREMENT PRIMARY KEY,
    name VARCHAR(100) NOT NULL,
    email VARCHAR(100) NOT NULL UNIQUE,
    password VARCHAR(255) NOT NULL,
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);

2.3. Database Connection (database.php)

PHP

class Database {
    private $host = 'localhost';
    private $db_name = 'testdb';
    private $username = 'root';
    private $password = '';
    public $conn;

    public function getConnection() {
        $this->conn = null;
        try {
            $this->conn = new PDO('mysql:host=' . $this->host . ';dbname=' . $this->db_name, $this->username, $this->password);
            $this->conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        } catch (PDOException $exception) {
            echo 'Connection error: ' . $exception->getMessage();
        }
        return $this->conn;
    }
}

2.4. User Model (models/User.php)

PHP

class User {
    private $conn;
    private $table_name = 'users';

    public $id;
    public $name;
    public $email;
    public $password;

    public function __construct($db) {
        $this->conn = $db;
    }

    public function read() {
        $query = 'SELECT id, name, email, created_at FROM ' . $this->table_name;
        $stmt = $this->conn->prepare($query);
        $stmt->execute();
        return $stmt;
    }

    public function create() {
        $query = 'INSERT INTO ' . $this->table_name . ' (name, email, password) VALUES (:name, :email, :password)';
        $stmt = $this->conn->prepare($query);

        $stmt->bindParam(':name', $this->name);
        $stmt->bindParam(':email', $this->email);
        $stmt->bindParam(':password', $this->password);

        return $stmt->execute();
    }
}

2.5. User Controller (controllers/UserController.php)

PHP

include_once '../database.php';
include_once '../models/User.php';

$database = new Database();
$db = $database->getConnection();
$user = new User($db);

if ($_SERVER['REQUEST_METHOD'] === 'GET') {
    $stmt = $user->read();
    $users = $stmt->fetchAll(PDO::FETCH_ASSOC);
    echo json_encode($users);
} elseif ($_SERVER['REQUEST_METHOD'] === 'POST') {
    $data = json_decode(file_get_contents('php://input'));

    $user->name = $data->name;
    $user->email = $data->email;
    $user->password = password_hash($data->password, PASSWORD_DEFAULT);

    if ($user->create()) {
        echo json_encode(['message' => 'User created successfully']);
    } else {
        echo json_encode(['message' => 'Unable to create user']);
    }
}

2.6. Main API File (index.php)

PHP

header('Access-Control-Allow-Origin: *');
header('Content-Type: application/json; charset=UTF-8');
header('Access-Control-Allow-Methods: GET, POST');
header('Access-Control-Allow-Headers: Content-Type');
include_once 'controllers/UserController.php';

3. Testing the API

Use Postman or cURL to test your API:

List Users:

curl -X GET http://localhost/api/index.php

Create User:

curl -X POST http://localhost/api/index.php \
     -H 'Content-Type: application/json' \
     -d '{"name": "John Doe", "email": "john@example.com", "password": "123456"}'