CRestUtil::getAuth

static function getAuth($appId, $appSecret, $scope, $additionalParams, $user_id = 0)
{
	global $USER;

	if(CModule::IncludeModule('oauth'))
	{
		if(is_array($scope))
		{
			$scope = implode(',', $scope);
		}

		$oauth = new BitrixOAuthClientApplication();
		$authParams = $oauth->getAuthorizeParamsInternal($appId, COAuthConstants::AUTH_RESPONSE_TYPE_AUTH_CODE, '', '', $scope, array(), $user_id > 0 ? $user_id : $USER->GetID());

		if(is_array($authParams) && isset($authParams[COAuthConstants::AUTH_RESPONSE_TYPE_AUTH_CODE]))
		{
			$res = $oauth->grantAccessTokenInternal($appId, COAuthConstants::GRANT_TYPE_AUTH_CODE, '', $authParams[COAuthConstants::AUTH_RESPONSE_TYPE_AUTH_CODE], $scope, $appSecret, '', $additionalParams, $user_id > 0 ? $user_id : $USER->GetID());

			return $res;
		}
	}

	return false;
}