return base64url_encode(openssl_random_pseudo_bytes(18));
}
// Generate a redirect URI corresponding to the given route.
// Note that OAuth 2.0 only allows HTTPS URLs in general, but Dropbox
// allows HTTP URLs for localhost/127.0.0.1 endpoints only.
function generate_redirect_uri($route_name)
{
$app = \Slim\Slim::getInstance();
$env = $app->environment();
return $env['slim.url_scheme'] . '://' . $_SERVER['HTTP_HOST'] . $app->urlFor($route_name);
}
// Main endpoint for the app. This page just starts the OAuth flow by
// redirecting the user to Dropbox to sign in (if necessary) and allow
// the app's request for access.
$app->get('/', function () use($app) {
$csrfToken = generateCSRFToken();
$_SESSION['csrfToken'] = $csrfToken;
// Redirect to the OAuth authorize endpoint, using the authorization
// code flow.
$app->redirect('https://www.dropbox.com/1/oauth2/authorize?' . http_build_query(array('response_type' => 'code', 'client_id' => $GLOBALS['APP_KEY'], 'redirect_uri' => generate_redirect_uri('callback'), 'state' => $csrfToken)));
});
// OAuth callback URL, which the user is redirected to by Dropbox after
// allowing access to the app. The query parameters will include an
// access code, which is then exchanged for an access token. The access
// token is what's used to make calls to the Dropbox API.
$app->get('/callback', function () use($app, $env) {
$params = array();
parse_str($env['QUERY_STRING'], $params);
// If there's an error, display it.
if (isset($params['error'])) {
echo 'Received an "' . $params['error'] . '" error with the message "' . $params['error_description'] . '"';
/**
* @return string
*/
public function csrfToken() : string
{
return generateCSRFToken();
}