How to Create RESTful API in PHP

In this tutorial we will learn how to create reate RESTful API in PHP.

How to Create RESTful API in PHP

Creating a RESTful API in PHP involves the following steps:

Step 1 - The HTTP methods and API endpoints should be defined: Select the HTTP methods that will be used to communicate with the API's public endpoints (such as GET, POST, PATCH PUT, and DELETE).

Step 2 - Set up the server environment: You will need a server to run the PHP code. You can either deploy your code to a production server or use a local development environment like XAMPP or WAMP.

Step 3 - Create PHP files for each endpoint: For each endpoint, create a PHP file that will handle requests and responses. Then an endpoint delivers a list of users, the file should be titled after that endpoint, such as "users.php".

Step 4 - Implement the API logic: In each PHP file, implement the logic that will handle the request and generate a response. This may entail running database queries, handling input data, and producing output in the desired format (for example, JSON or XML).

Step 5 - Handle errors and exceptions: Handle any errors or exceptions that may occur during API calls and return appropriate error responses with meaningful error messages.

Step 6 - Test the API: Test the API endpoints using a tool like Postman or a simple web form to ensure that they are working as expected.

Here's an example of a simple RESTful API in PHP that returns a list of users:

GET /users: Create a new user.

// users.php

// Set the content type to JSON
header('Content-Type: application/json');

// Define the list of users
$users = array(
    array('id' => 1, 'name' => 'John'),
    array('id' => 2, 'name' => 'Jane'),
    array('id' => 3, 'name' => 'Bob'),
);

// Handle GET requests to /users
if ($_SERVER['REQUEST_METHOD'] == 'GET' && strpos($_SERVER['REQUEST_URI'], '/users') === 0) {
    // Return the list of users
    echo json_encode($users);
} else {
    // Return a 404 error
    http_response_code(404);
    echo json_encode(array('error' => 'Endpoint not found'));
}

POST /users: Create a new user.

// users.php

if ($_SERVER['REQUEST_METHOD'] == 'POST' && strpos($_SERVER['REQUEST_URI'], '/users') === 0) {
    // Get the user data from the request body
    $data = json_decode(file_get_contents('php://input'), true);
    
    // Validate the user data
    if (!isset($data['name']) || !isset($data['email'])) {
        http_response_code(400);
        echo json_encode(array('error' => 'Invalid user data'));
        exit;
    }
    
    // Save the user to the database
    // ...
    
    // Return the new user ID
    http_response_code(201);
    echo json_encode(array('id' => $newUserId));
} else {
    http_response_code(404);
    echo json_encode(array('error' => 'Endpoint not found'));
}

PUT /users/{id}: Update an existing user.

// users.php

if ($_SERVER['REQUEST_METHOD'] == 'PUT' && preg_match('/^\/users\/(\d+)$/', $_SERVER['REQUEST_URI'], $matches)) {
    // Get the user ID from the URL
    $userId = $matches[1];
    
    // Get the user data from the request body
    $data = json_decode(file_get_contents('php://input'), true);
    
    // Validate the user data
    if (!isset($data['name']) || !isset($data['email'])) {
        http_response_code(400);
        echo json_encode(array('error' => 'Invalid user data'));
        exit;
    }
    
    // Update the user in the database
    // ...
    
    // Return a success message
    http_response_code(200);
    echo json_encode(array('message' => 'User updated successfully'));
} else {
    http_response_code(404);
    echo json_encode(array('error' => 'Endpoint not found'));
}

PATCH /users/{id}: Partially update an existing user.

// users.php

if ($_SERVER['REQUEST_METHOD'] == 'PATCH' && preg_match('/^\/users\/(\d+)$/', $_SERVER['REQUEST_URI'], $matches)) {
    // Get the user ID from the URL
    $userId = $matches[1];
    
    // Get the user data from the request body
    $data = json_decode(file_get_contents('php://input'), true);
    
    // Update the user in the database
    // ...
    
    // Return a success message
    http_response_code(200);
    echo json_encode(array('message' => 'User updated successfully'));
} else {
    http_response_code(404);
    echo json_encode(array('error' => 'Endpoint not found'));
}

DELETE /users/{id}: Delete an existing user.

// users.php

if ($_SERVER['REQUEST_METHOD'] == 'DELETE' && preg_match('/^\/users\/(\d+)$/', $_SERVER['REQUEST_URI'], $matches)) {
    // Get the user ID from the URL
    $userId = $matches[1];
    
    // Delete the user from the database
    // ...
    
    // Return a success message
    http_response_code(200);
    echo json_encode(array('message' => 'User deleted successfully'));
} else {
    http_response_code(404);
    echo json_encode(array('error' => 'Endpoint not found'));
}

Some examples of how you can implement different HTTP methods in a PHP RESTful API.