How to Access QuickBooks Online API in PHP

Understanding QuickBooks Online API Access

• Familiarize yourself with the QuickBooks Online API documentation. It provides detailed information on endpoints, authentication, and limits.

 

• You typically interact with QuickBooks Online API using OAuth 2.0 for authentication, and RESTful HTTP requests because of its stateless server to client communication.

Set Up Your PHP Environment

• Ensure you have PHP installed with necessary extensions like `cURL` and `OpenSSL` for HTTPS requests.

 

• Install a library to handle OAuth 2.0 authentication. One popular choice is `thephpleague/oauth2-client`.

composer require league/oauth2-client

Create Your OAuth 2.0 Client

• Create a PHP script where you'll define your OAuth 2.0 client’s credentials including client ID, client secret, redirect URI, and authorization URLs.

require 'vendor/autoload.php';
use League\OAuth2\Client\Provider\GenericProvider;

$provider = new GenericProvider([
    'clientId'                => 'YOUR_CLIENT_ID',   
    'clientSecret'            => 'YOUR_CLIENT_SECRET',   
    'redirectUri'             => 'YOUR_REDIRECT_URI',
    'urlAuthorize'            => 'https://appcenter.intuit.com/connect/oauth2',
    'urlAccessToken'          => 'https://oauth.platform.intuit.com/oauth2/v1/tokens/bearer',
    'urlResourceOwnerDetails' => 'https://sandbox-quickbooks.api.intuit.com/v3/company'
]);

Authenticate and Obtain Access Token

• Direct the user to the QuickBooks Online authorization page, which will redirect back with an authorization code after user consent.

 

• Exchange the authorization code for an access token that grants API access.

session_start();

// Redirect to QuickBooks Online Authorization URL
if (!isset($_GET['code'])) {
    $authorizationUrl = $provider->getAuthorizationUrl();
    $_SESSION['oauth2state'] = $provider->getState();
    header('Location: ' . $authorizationUrl);
    exit;
}

// Check given state against previously stored one to mitigate CSRF attack
elseif (empty($_GET['state']) || ($_GET['state'] !== $_SESSION['oauth2state'])) {
    unset($_SESSION['oauth2state']);
    exit('Invalid state');
}

// Get an access token using the authorization code grant
try {
    $accessToken = $provider->getAccessToken('authorization_code', [
        'code' => $_GET['code']
    ]);
} catch (\League\OAuth2\Client\Provider\Exception\IdentityProviderException $e) {
    exit($e->getMessage());
}

Make API Requests

• Now with access token, you can make authenticated API requests to QuickBooks Online API endpoints to fetch or update data.

 

• Use `cURL` or a suitable library for HTTP requests in PHP, making sure you pass your access token in the authorization header.

$curl = curl_init();

curl_setopt_array($curl, [
    CURLOPT_URL => "https://sandbox-quickbooks.api.intuit.com/v3/company/YOUR_COMPANY_ID/query?query=SELECT%20*%20FROM%20Customer",
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        "Authorization: Bearer {$accessToken->getToken()}",
        "Accept: application/json"
    ],
]);

$response = curl_exec($curl);
curl_close($curl);
$data = json_decode($response, true);

print_r($data);