Laravel5.4での複数フィールドログインの実装方法について

/**
  * Handle a login request to the application.
  *
  * @param \Illuminate\Http\Request $request
  * @return \Illuminate\Http\RedirectResponse|\Illuminate\Http\Response
  */
 public function login(Request $request)
 {
  // 表单验证
  $this->validateLogin($request);

  // If the class is using the ThrottlesLogins trait, we can automatically throttle
  // the login attempts for this application. We'll key this by the username and
  // the IP address of the client making these requests into this application.
  // 防止暴力破解，多次登录失败会根据IP锁定
  if ($this->hasTooManyLoginAttempts($request)) {
   $this->fireLockoutEvent($request);

   return $this->sendLockoutResponse($request);
  }
  
  // 这个就是主要的负责判断数据库中是否存在相应的账号和密码的地方，我们需要重写的就是attemptLogin方法
  if ($this->attemptLogin($request)) {
   return $this->sendLoginResponse($request);
  }

  // If the login attempt was unsuccessful we will increment the number of attempts
  // to login and redirect the user back to the login form. Of course, when this
  // user surpasses their maximum number of attempts they will get locked out.
  // 登录失败，失败次数++，防止暴力破解
  $this->incrementLoginAttempts($request);

  // 返回失败响应
  return $this->sendFailedLoginResponse($request);
 }

/**
  * Attempt to log the user into the application.
  *
  * @param \Illuminate\Http\Request $request
  * @return bool
  */
 protected function attemptLogin(Request $request)
 {
  return $this->guard()->attempt(
   $this->credentials($request), $request->has('remember')
  );
 }

public function attemptLogin(Request $request)
 {
  $username = $request->input('username');
  $password = $request->input('password');

  // 验证用户名登录方式
  $usernameLogin = $this->guard()->attempt(
   ['username' => $username, 'password' => $password], $request->has('remember')
  );
  if ($usernameLogin) {
   return true;
  }

  // 验证手机号登录方式
  $mobileLogin = $this->guard()->attempt(
   ['mobile' => $username, 'password' => $password], $request->has('remember')
  );
  if ($mobileLogin) {
   return true;
  }

  // 验证邮箱登录方式
  $emailLogin = $this->guard()->attempt(
   ['email' => $username, 'password' => $password], $request->has('remember')
  );
  if ($emailLogin) {
   return true;
  }

  return false;
 }