Why Build a REST API?
Ever wondered how apps talk to each other? It’s not through secret handshakes—it’s via REST APIs! Whether you’re building a mobile app, a fancy JavaScript frontend, or an AI-powered robot that needs data, a REST API is the way to go!
Let’s dive in and build a REST API in PHP!
What’s a REST API? (And Why Should We Care?)
A REST API (Representational State Transfer API) allows different applications to communicate over the internet using HTTP requests. It’s like a waiter at a restaurant—
- You ask for food (a request)
- The kitchen prepares the food (processes the request)
- The waiter delivers your food (a response)
Common REST Methods:
- GET → Retrieve data (e.g., Get all users)
- POST → Send data (e.g., Create a new user)
- PUT → Update data (e.g., Update user info)
- DELETE → Remove data (e.g., Delete a user)
Now, let’s build our own API!
Step 1: Creating a Simple REST API in PHP
Setting Up api.php
First, let’s create a file called api.php and start handling requests.
header("Content-Type: application/json");
$requestMethod = $_SERVER["REQUEST_METHOD"];
if ($requestMethod === "GET") {
echo json_encode(["message" => "Hello from the API!", "status" => "success"]);
} else {
echo json_encode(["error" => "Invalid request method", "status" => "failed"]);
}
Now, if you visit api.php in the browser, you’ll see:
{
"message": "Hello from the API!",
"status": "success"
}
Step 2: Handling Different Requests
Let’s improve our API to handle GET, POST, PUT, and DELETE requests.
api.php (Full Version)
header("Content-Type: application/json");
$requestMethod = $_SERVER["REQUEST_METHOD"];
$data = json_decode(file_get_contents("php://input"), true);
switch ($requestMethod) {
case "GET":
echo json_encode(["message" => "This is a GET request", "data" => ["id" => 1, "name" => "Alice"]]);
break;
case "POST":
echo json_encode(["message" => "Data received!", "data" => $data]);
break;
case "PUT":
echo json_encode(["message" => "Data updated!", "data" => $data]);
break;
case "DELETE":
echo json_encode(["message" => "Data deleted successfully"]);
break;
default:
echo json_encode(["error" => "Invalid request method"]);
break;
}
Now, our API can handle:
- GET → Fetching data
- POST → Sending new data
- PUT → Updating existing data
- DELETE → Removing data
Step 3: Testing the API (Like a Mad Scientist!)
To test our API, we can use:
- Postman → A free tool for making API requests
- cURL (Command Line)
Testing with cURL
GET Request:
curl -X GET http://localhost/api.php
POST Request:
curl -X POST -d '{"name":"John Doe"}' -H "Content-Type: application/json" http://localhost/api.php
PUT Request:
curl -X PUT -d '{"name":"Updated User"}' -H "Content-Type: application/json" http://localhost/api.php
DELETE Request:
curl -X DELETE http://localhost/api.php
Step 4: Building a Real-World API (User Management)
Let’s create a User Management API that connects to a database!
Database Setup (users.sql)
CREATE TABLE users (
id INT AUTO_INCREMENT PRIMARY KEY,
name VARCHAR(100) NOT NULL,
email VARCHAR(100) NOT NULL UNIQUE
);
users.php
$pdo = new PDO("mysql:host=localhost;dbname=mydb", "root", "");
header("Content-Type: application/json");
$requestMethod = $_SERVER["REQUEST_METHOD"];
if ($requestMethod === "GET") {
$stmt = $pdo->query("SELECT * FROM users");
echo json_encode($stmt->fetchAll(PDO::FETCH_ASSOC));
}
Now, your API can fetch users from the database!
Congrats! You’ve just built a REST API from scratch in PHP! Here’s what you learned: What a REST API is, How to handle GET, POST, PUT, DELETE, How to connect an API to a database.
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