if ( !Auth::guest() )
{
  return Redirect::to('/dashboard');
}

class Auth extends Facade {
  /**
   * Get the registered name of the component.
   *
   * @return string
   */
  protected static function getFacadeAccessor() { return 'auth'; }
}

$this->app->bindShared('auth', function($app)
{
  // Once the authentication service has actually been requested by the developer
  // we will set a variable in the application indicating such. This helps us
  // know that we need to set any queued cookies in the after event later.
  $app['auth.loaded'] = true;
  return new AuthManager($app);
});

Illuminate\Support\Facades\Auth::guest()
Illuminate\Support\Facades\Facade::__callStatic
Illuminate\Auth\AuthManager->guest()
Illuminate\Support\Manager->__call
public function __call($method, $parameters)
{
    return call_user_func_array(array($this->driver(), $method), $parameters);
}

public function driver($driver = null)
{
    $driver = $driver "color: #0000ff">getDefaultDrive方法



/**
* Get the default authentication driver name.
*
* @return string
*/
public function getDefaultDriver()
{
    return $this->app['config']['auth.driver'];
}




最终调用的是配置文件中配置的driver，如果配的是


'driver' => 'eloquent'




则调用的是


public function createEloquentDriver()
{
    $provider = $this->createEloquentProvider();
    return new Guard($provider, $this->app['session.store']);
}




所以Auth::guest最终调用的是Guard::guest方法
这里的逻辑先从session中取用户信息，奇怪的是session里只保存的是用户ID，然后拿这个ID来从数据库中取用户信息


public function user()
{
    if ($this->loggedOut) return;
    // If we have already retrieved the user for the current request we can just
    // return it back immediately. We do not want to pull the user data every
    // request into the method because that would tremendously slow an app.
    if ( ! is_null($this->user))
    {
      return $this->user;
    }
    $id = $this->session->get($this->getName());
    // First we will try to load the user using the identifier in the session if
    // one exists. Otherwise we will check for a "remember me" cookie in this
    // request, and if one exists, attempt to retrieve the user using that.
    $user = null;
    if ( ! is_null($id))
    {
      //provider为EloquentUserProvider
     $user = $this->provider->retrieveByID($id);
    }
    // If the user is null, but we decrypt a "recaller" cookie we can attempt to
    // pull the user data on that cookie which serves as a remember cookie on
    // the application. Once we have a user we can return it to the caller.
    $recaller = $this->getRecaller();
    if (is_null($user) && ! is_null($recaller))
    {
      $user = $this->getUserByRecaller($recaller);
    }
    return $this->user = $user;
}




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