public function logout(HTTPRequest $request)
    {
        $email = $request->requestVar('email');
        $member = Member::get()->filter(array('Email' => $email))->first();

        if ($member) {
            //logout
            $member->logout();

            if ($this->tokenConfig['owner'] === Member::class) {
                //generate expired token
                $tokenData = $this->generateToken(true);

                //write
                $tokenDBColumn = $this->tokenConfig['DBColumn'];
                $expireDBColumn = $this->tokenConfig['expireDBColumn'];

                $member->{$tokenDBColumn} = $tokenData['token'];
                $member->{$expireDBColumn} = $tokenData['expire'];
                $member->write();
            }
        }
    }