Consuming APIs Using cURL

Tutorial 2 of 5

1. Introduction

1.1 Goal of the Tutorial

This tutorial aims to provide a detailed guide on how to consume REST APIs using cURL in PHP. By the end of this tutorial, you will be able to retrieve, create, update, and delete data from an API using HTTP requests.

1.2 Learning Outcomes

Understanding what cURL is and how it works
Understanding how to use cURL to make GET, POST, PUT, and DELETE requests
Knowing how to handle API responses

1.3 Prerequisites

Basic knowledge of PHP
A working PHP development environment

2. Step-by-Step Guide

cURL is a tool to transfer data from or to a server, using one of the supported protocols (HTTP, HTTPS, FTP, etc.). PHP supports libcurl, which adds the ability for PHP to make cURL requests.

2.1 Making a GET Request

Fetch data from an API using a GET request. This is the most common type of HTTP request, used to retrieve data.

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => "http://example.com/api/resource",
  CURLOPT_RETURNTRANSFER => true,
));

$response = curl_exec($curl);

curl_close($curl);

echo $response;

2.2 Making a POST Request

Send data to an API using a POST request. This request is used to create data.

$curl = curl_init();

$data = array(
    'key1' => 'value1',
    'key2' => 'value2',
);

curl_setopt_array($curl, array(
  CURLOPT_URL => "http://example.com/api/resource",
  CURLOPT_POST => true,
  CURLOPT_POSTFIELDS => $data,
  CURLOPT_RETURNTRANSFER => true,
));

$response = curl_exec($curl);

curl_close($curl);

echo $response;

3. Code Examples

3.1 GET Request

// Initialize cURL
$curl = curl_init();

// Set cURL options
curl_setopt_array($curl, array(
  CURLOPT_URL => "http://example.com/api/resource",  // API URL
  CURLOPT_RETURNTRANSFER => true,  // Return the result as a string
));

// Execute the cURL session
$response = curl_exec($curl);

// Close the cURL session
curl_close($curl);

// Print the response
echo $response;

3.2 POST Request

// Initialize cURL
$curl = curl_init();

// Data to be sent
$data = array(
    'key1' => 'value1',
    'key2' => 'value2',
);

// Set cURL options
curl_setopt_array($curl, array(
  CURLOPT_URL => "http://example.com/api/resource",  // API URL
  CURLOPT_POST => true,  // Set the request method to POST
  CURLOPT_POSTFIELDS => $data,  // Set the POST fields
  CURLOPT_RETURNTRANSFER => true,  // Return the result as a string
));

// Execute the cURL session
$response = curl_exec($curl);

// Close the cURL session
curl_close($curl);

// Print the response
echo $response;

4. Summary

In this tutorial, we've explored how to use cURL in PHP to consume APIs. We learned to make GET and POST requests and handle responses. As next steps, try to make PUT and DELETE requests.

5. Practice Exercises

Make a GET request to any public API and print the response.
Make a POST request to any public API with dummy data and print the response.

Solutions

GET request

$curl = curl_init();

curl_setopt_array($curl, array(
  CURLOPT_URL => "https://api.publicapis.org/entries",
  CURLOPT_RETURNTRANSFER => true,
));

$response = curl_exec($curl);

curl_close($curl);

echo $response;

POST request

$curl = curl_init();

$data = array(
    'key1' => 'value1',
    'key2' => 'value2',
);

curl_setopt_array($curl, array(
  CURLOPT_URL => "http://dummy.restapiexample.com/api/v1/create",
  CURLOPT_POST => true,
  CURLOPT_POSTFIELDS => $data,
  CURLOPT_RETURNTRANSFER => true,
));

$response = curl_exec($curl);

curl_close($curl);

echo $response;