PHP and APIs: Fetching Data with cURL and Guzzle 🚀

APIs (Application Programming Interfaces) allow PHP applications to fetch data from external services, such as:
✅ Weather APIs 🌦️
✅ Cryptocurrency rates 💰
✅ User authentication systems 🔑
✅ Payment gateways (PayPal, Stripe) 💳

In this guide, you’ll learn:
✅ How to send GET & POST requests using cURL
✅ How to fetch JSON responses from APIs
✅ How to use Guzzle (a modern alternative to cURL)
✅ How to build a mini project that fetches real-world API data

Let’s get started! 🚀

1️⃣ What is cURL in PHP?

💡 cURL (Client URL) is a PHP extension that allows you to send HTTP requests to APIs.

🔥 Why use cURL?
✅ Supports GET, POST, PUT, DELETE requests.
✅ Works with JSON APIs.
✅ Supports authentication (Bearer Token, API Key, OAuth).

2️⃣ Making a GET Request with cURL

Let’s fetch random user data from the Random User API.

<?php
$url = "https://randomuser.me/api/";
$ch = curl_init($url);

curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
$response = curl_exec($ch);
curl_close($ch);

$data = json_decode($response, true);
echo "Random User: " . $data["results"][0]["name"]["first"] . " " . $data["results"][0]["name"]["last"];
?>

🔥 What’s happening?
✅ curl_init($url) initializes the request.
✅ CURLOPT_RETURNTRANSFER stores the API response in a variable.
✅ json_decode($response, true) converts JSON into an array.

3️⃣ Sending a POST Request with cURL

Let’s send a POST request to a fake API (reqres.in).

<?php
$url = "https://reqres.in/api/users";
$data = ["name" => "Zero Dev", "job" => "PHP Developer"];

$ch = curl_init($url);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($data));
curl_setopt($ch, CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

$response = curl_exec($ch);
curl_close($ch);

echo $response;
?>

🔥 What’s happening?
✅ CURLOPT_POST enables POST requests.
✅ CURLOPT_POSTFIELDS sends JSON data.
✅ CURLOPT_HTTPHEADER sets headers.

4️⃣ Fetching API Data with Guzzle (Better Than cURL)

💡 Guzzle is a modern HTTP client for PHP. It’s easier to use than cURL!

1️⃣ Install Guzzle via Composer

composer require guzzlehttp/guzzle

2️⃣ Fetching a GET Request

<?php
require "vendor/autoload.php";

use GuzzleHttp\Client;

$client = new Client();
$response = $client->get("https://randomuser.me/api/");
$data = json_decode($response->getBody(), true);

echo "User: " . $data["results"][0]["name"]["first"] . " " . $data["results"][0]["name"]["last"];
?>

🔥 Why use Guzzle?
✅ Cleaner syntax than cURL.
✅ Handles timeouts, headers, and JSON easily.

5️⃣ Sending a POST Request with Guzzle

<?php
require "vendor/autoload.php";

use GuzzleHttp\Client;

$client = new Client();
$response = $client->post("https://reqres.in/api/users", [
    'json' => ["name" => "Zero Dev", "job" => "PHP Developer"]
]);

echo $response->getBody();
?>

🔥 What’s happening?
✅ post() method sends JSON data.
✅ json option handles encoding automatically.

6️⃣ Handling API Authentication

1️⃣ Basic Authentication

<?php
$client = new Client(['auth' => ['username', 'password']]);
$response = $client->get("https://api.example.com/protected");
echo $response->getBody();
?>

2️⃣ Bearer Token Authentication

<?php
$client = new Client([
    'headers' => ['Authorization' => 'Bearer YOUR_ACCESS_TOKEN']
]);
$response = $client->get("https://api.example.com/protected");
echo $response->getBody();
?>

🔥 Why use authentication?
✅ Needed for APIs like GitHub, Stripe, OpenAI, and Twitter.

🎯 Mini Project: Weather API Fetcher

Let’s build a weather app using the OpenWeather API.

1️⃣ Get Your Free API Key

2️⃣ Install Guzzle

composer require guzzlehttp/guzzle

3️⃣ Create `weather.php`

<?php
require "vendor/autoload.php";

use GuzzleHttp\Client;

$apiKey = "YOUR_API_KEY"; // Replace with your OpenWeather API key
$city = "Austin";
$client = new Client();
$response = $client->get("https://api.openweathermap.org/data/2.5/weather", [
    'query' => ['q' => $city, 'appid' => $apiKey, 'units' => 'metric']
]);

$data = json_decode($response->getBody(), true);
echo "Weather in " . $data["name"] . ": " . $data["weather"][0]["description"] . ", " . $data["main"]["temp"] . "°C";
?>

🔥 Try running it in the browser!

http://localhost/weather.php

💥 Boom! You just built a weather API fetcher! 🎉

🚀 Final Thoughts

Now you know how to fetch data from APIs like a pro!
✅ Use cURL for simple API requests
✅ Use Guzzle for advanced API handling
✅ Handle authentication securely
✅ Build real-world projects with APIs

👉 Next: Introduction to PHP Frameworks

Happy coding! 🎉🚀