$provider = new Cargix1\OAuth2\Client\Provider\Shopify([ 'clientId' => '{shopify-client-id}', 'clientSecret' => '{shopify-client-secret}', 'redirectUri' => 'https://example.com/callback-url', 'scopes' => '{shopify-scopes}', 'nonce' => '{nonce}' ]); if (!isset($_GET['code'])) { // If we don't have an authorization code then get one $authUrl = $provider->getAuthorizationUrl(); $_SESSION['oauth2state'] = $provider->state; header('Location: '.$authUrl); 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'); } else { // Try to get an access token (using the authorization code grant) $token = $provider->getAccessToken('authorization_code', [ 'code' => $_GET['code'] ]); // Optional: Now you have a token you can look up a users profile data try { // We got an access token, let's now get the user's details $userDetails = $provider->getUserDetails($token); // Use these details to create a new profile printf('Hello %s!', $userDetails->firstName); } catch (Exception $e) { // Failed to get user details exit('Oh dear...'); } // Use this to interact with an API on the users behalf echo $token->accessToken; }