传递给 Illuminate\Auth\Guard::login() 的参数 1 必须实现接口 Illuminate\Auth\UserInterface，给定 open 为 null：

我使用 OAuth2 执行 Facebook 登录，然后使用 Laravel 4 的内置身份验证系统让用户在重新访问时重新登录。对于大多数用户来说，我认为我所拥有的没有任何问题，但对于一名用户来说，他在登录时看到以下错误：

ErrorException
Argument 1 passed to Illuminate\Auth\Guard::login() must implement interface Illuminate\Auth\UserInterface, null given
open: */nfs/c09/h04/mnt/139243/domains/crowdsets.com/vendor/laravel/framework/src/Illuminate/Auth/Guard.php
*        /**
        * Log a user into the application.
        *
        * @param  \Illuminate\Auth\UserInterface  $user
        * @param  bool  $remember
        * @return void
        */
       public function login(UserInterface $user, $remember = false)
       {
               $id = $user->getAuthIdentifier();

以下是控制器中的相关登录/身份验证代码：

$check = Fan::where('fbid', '=', $user['uid'])->first();

                if(is_null($check)) {

                  $fan = new Fan;

                  $fan->fbid = $user['uid'];
                  $fan->email = $user['email'];
                  $fan->first_name = $user['first_name'];
                  $fan->last_name = $user['last_name'];
                  $fan->gender = $user['gender'];
                  $fan->birthday = $user['birthday'];
                  $fan->age = $age;
                  $fan->city = $city;
                  $fan->state = $state_abbrev;
                  $fan->image = $user['image'];
                  $fan->friend_ids_url = $user['friends'];
                  $fan->friend_ids_unpacked = $friend_ids;

                  $fan->save();

                  $new = Fan::where('fbid', '=', $user['uid'])->first();

                  Auth::login($new);
                  return Redirect::to('fans/home');

                }

               else {

                  Auth::login($check);

                  $fan = Fan::find(Auth::user()->id);
                  $fan->image = $user['image'];
                  $fan->save();

                  return Redirect::to('fans/home');
                  var_dump($user);

               }

这是我用来保存用户信息的表模型中的代码，称为“粉丝”：

<?php

use Illuminate\Auth\UserInterface;

class Fan extends Eloquent implements UserInterface {
    protected $guarded = array();

    public static $rules = array();

    public function getAuthIdentifier() 
{ 
return $this->getKey(); 
}


public function getAuthPassword() 
{ 
return $this->password; 
}

这非常令人困惑，因为此登录适用于我尝试过的所有其他配置文件。只有这位朋友的个人资料才会引发此错误。我还将添加，在登录（或重试）时，它将在数据库/表中为此用户创建多个条目。建立这个认证系统就是为了防止这种情况发生。我有什么遗漏的吗？

在 LoginController 的 create() 方法中，您必须返回 $user

protected function create(array $data)
    {
        $user = User::create([
            'username' => $data['username'],
            'email' => $data['email'],
            'password' => bcrypt($data['password']),
        ]);

        return $user;
    }