What are the challenges of integrating Exchange Online Calendar with PHP?

One challenge of integrating Exchange Online Calendar with PHP is the lack of official PHP SDKs or libraries provided by Microsoft for interacting with their APIs. However, this can be overcome by using third-party libraries such as Microsoft Graph SDK for PHP, which provides a wrapper around the Microsoft Graph API.

// Include the Microsoft Graph SDK for PHP
require_once 'vendor/autoload.php';

use Microsoft\Graph\Graph;
use Microsoft\Graph\Model;

// Initialize the Graph object with the access token
$graph = new Graph();
$graph->setAccessToken('YOUR_ACCESS_TOKEN_HERE');

// Retrieve the user's events from Exchange Online Calendar
$events = $graph->createRequest('GET', '/me/events')
    ->setReturnType(Model\Event::class)
    ->execute();

// Loop through the events and display them
foreach ($events as $event) {
    echo $event->getSubject() . ' - ' . $event->getStart()->getDateTime() . '<br>';
}