API::initSession PHP Method

    protected function initSession($params = array())
    {
        global $CFG_GLPI;
        $this->checkAppToken();
        $this->logEndpointUsage(__FUNCTION__);
        if ((!isset($params['login']) || empty($params['login']) || !isset($params['password']) || empty($params['password'])) && (!isset($params['user_token']) || empty($params['user_token']))) {
            $this->returnError(__("parameter(s) login, password or user_token are missing"), 400, "ERROR_LOGIN_PARAMETERS_MISSING");
        }
        $auth = new Auth();
        // fill missing params (in case of user_token)
        if (!isset($params['login'])) {
            $params['login'] = '';
        }
        if (!isset($params['password'])) {
            $params['password'] = '';
        }
        $noAuto = true;
        if (isset($params['user_token']) && !empty($params['user_token'])) {
            $_REQUEST['user_token'] = $params['user_token'];
            $noAuto = false;
        } else {
            if (!$CFG_GLPI['enable_api_login_credentials']) {
                $this->returnError(__("usage of initSession resource with credentials is disabled"), 400, "ERROR_LOGIN_WITH_CREDENTIALS_DISABLED", false);
            }
        }
        // login on glpi
        if (!$auth->Login($params['login'], $params['password'], $noAuto)) {
            $err = Html::clean($auth->getErr());
            if (isset($params['user_token']) && !empty($params['user_token'])) {
                return $this->returnError(__("parameter user_token seems invalid"), 401, "ERROR_GLPI_LOGIN_USER_TOKEN", false);
            }
            return $this->returnError($err, 401, "ERROR_GLPI_LOGIN", false);
        }
        // stop session and return session key
        session_write_close();
        return array('session_token' => $_SESSION['valid_id']);
    }