本文实例讲述了Laravel框架用户登陆身份验证实现方法。分享给大家供大家参考，具体如下：

laravel中检测用户是否登录，有以下的代码：

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

那Auth::guest是如何调用的呢？

laravel用了Facade模式，相关门面类在laravel/framework/src/Illuminate/Support/Facades文件夹定义的，看下Auth类的定义：

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

laravel框架中，Facade模式使用反射，相关方法其实调用app['auth']中的方法，app['auth']是什么时候创建的呢，

AuthServiceProvider::register方法会注册：

$this->app->bindShared('auth', function($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);
});

那为什么最终会调到哪里呢，看下堆栈：

IlluminateSupportFacadesAuth::guest()
IlluminateSupportFacadesFacade::__callStatic
IlluminateAuthAuthManager->guest()
IlluminateSupportManager->__call
public function __call($method, $parameters)
{
    return call_user_func_array(array($this->driver(), $method), $parameters);
}

看下driver的代码：

public function driver($driver = null)
{
    $driver = $driver ?: $this->getDefaultDriver();
    // If the given driver has not been created before, we will create the instances
    // here and cache it so we can return it next time very quickly. If there is
    // already a driver created by this name, we'll just return that instance.
    if ( ! isset($this->drivers[$driver]))
    {
      $this->drivers[$driver] = $this->createDriver($driver);
    }
    return $this->drivers[$driver];
}

没有会调用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;
}

更多关于Laravel相关内容感兴趣的读者可查看本站专题：《Laravel框架入门与进阶教程》、《php优秀开发框架总结》、《php面向对象程序设计入门教程》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》

希望本文所述对大家基于Laravel框架的PHP程序设计有所帮助。