Laravel 源码解读系列第四篇-Auth 机制

前言

Laravel有一个神器:

php artisan make:auth

能够快速的帮我们完成一套注册和登录的认证机制，但是这套机制具体的是怎么跑起来的呢？我们不妨来一起看看他的源码。不过在这篇文章中，我只会阐述大致的流程，至于一些具体的细节，比如他的登录次数限制是怎么完成的之类的不妨自己去寻找答案。
源码解读系列，有兴趣的小伙伴可以点个star，我会持续更新各个部分的解读，也是和大家一起进步的一个过程，如有写的不对的地方还望指出。

过程

路由

当我们执行完命令之后，我们会发现，在routes/web.php中多了这样一行代码:

Auth::routes();

结合我们在前面讲到的Facades，我们会执行Facades/Auth.php的routes方法:

public static function routes()
    {
        static::$app->make('router')->auth();
    }

而$app->make('router')会返回一个Routing/Router.php对象的实例，而他的auth方法是:

public function auth()
    {
        // Authentication Routes...
        $this->get('login', 'AuthLoginController@showLoginForm')->name('login');
        $this->post('login', 'AuthLoginController@login');
        $this->post('logout', 'AuthLoginController@logout')->name('logout');

        // Registration Routes...
        $this->get('register', 'AuthRegisterController@showRegistrationForm')->name('register');
        $this->post('register', 'AuthRegisterController@register');

        // Password Reset Routes...
        $this->get('password/reset', 'AuthForgotPasswordController@showLinkRequestForm')->name('password.request');
        $this->post('password/email', 'AuthForgotPasswordController@sendResetLinkEmail')->name('password.email');
        $this->get('password/reset/{token}', 'AuthResetPasswordController@showResetForm')->name('password.reset');
        $this->post('password/reset', 'AuthResetPasswordController@reset');
    }

而这里的get和post方法，其实也就是我们通过Route::get等最终会调用的方法。

注册

我们直接看表单提交的方法:

        $this->post('register', 'AuthRegisterController@register');

//RegisterController.php
class RegisterController extends Controller
{
    /*
    |--------------------------------------------------------------------------
    | Register Controller
    |--------------------------------------------------------------------------
    |
    | This controller handles the registration of new users as well as their
    | validation and creation. By default this controller uses a trait to
    | provide this functionality without requiring any additional code.
    |
    */

    use RegistersUsers;

    /**
     * Where to redirect users after registration.
     *
     * @var string
     */
    protected $redirectTo = '/home';

    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this->middleware('guest');
    }

    /**
     * Get a validator for an incoming registration request.
     *
     * @param  array  $data
     * @return IlluminateContractsValidationValidator
     */
    protected function validator(array $data)
    {
        return Validator::make($data, [
            'name' => 'required|string|max:255',
            'email' => 'required|string|email|max:255|unique:users',
            'password' => 'required|string|min:6|confirmed',
        ]);
    }

    /**
     * Create a new user instance after a valid registration.
     *
     * @param  array  $data
     * @return User
     */
    protected function create(array $data)
    {
        return User::create([
            'name' => $data['name'],
            'email' => $data['email'],
            'password' => bcrypt($data['password']),
        ]);
    }
}

里面使用到了RegistersUsers这个trait，里面就有我们需要的register方法:

public function register(Request $request)
    {
        $this->validator($request->all())->validate();

        event(new Registered($user = $this->create($request->all())));

//        默认情况下,$this->guard()会返回一个`SessionGuard`的对象
        $this->guard()->login($user);

        return $this->registered($request, $user)
                        ?: redirect($this->redirectPath());
    }

    protected function guard()
    {
        return Auth::guard();
    }

其中最核心的部分就是:

$this->guard()->login($user);

而$this->guard()在默认配置下会返回一个SessionGuard的对象，具体是这样实现的:

前面我们有讲过，当我们执行Facades下一个不存在的方法时，我们会调用Facade.php的__callStatic方法，这个方法会获取当前对象的getFacadeAccessor方法而返回一个对应的对象并调用他所需要调用的方法，这个详细过程在我的第三篇中都有所阐述。
而auth的别名绑定，是在我们初始化的过程中绑定的，具体可以看我写的第一篇，所以，这里我们会调用AuthManager这个对象:

 public function guard($name = null)
    {
        $name = $name ?: $this->getDefaultDriver();

        return isset($this->guards[$name])
                    ? $this->guards[$name]
                    : $this->guards[$name] = $this->resolve($name);
    }

public function getDefaultDriver()
    {
        return $this->app['config']['auth.defaults.guard'];
    }

protected function resolve($name)
    {
        $config = $this->getConfig($name);

        if (is_null($config)) {
            throw new InvalidArgumentException("Auth guard [{$name}] is not defined.");
        }

        if (isset($this->customCreators[$config['driver']])) {
            return $this->callCustomCreator($name, $config);
        }

        $driverMethod = 'create'.ucfirst($config['driver']).'Driver';

        if (method_exists($this, $driverMethod)) {
            return $this->{$driverMethod}($name, $config);
        }

        throw new InvalidArgumentException("Auth guard driver [{$name}] is not defined.");
    }

//config/auth.php

'defaults' => [
        'guard' => 'web',
        'passwords' => 'users',
    ],

    'guards' => [
        'web' => [
            'driver' => 'session',
            'provider' => 'users',
        ],

        'api' => [
            'driver' => 'token',
            'provider' => 'users',
        ],
    ],

通过调用AuthManager可以拼接得出，最终他会调用一个createSessionDriver方法:

public function createSessionDriver($name, $config)
    {
        $provider = $this->createUserProvider($config['provider']);

        $guard = new SessionGuard($name, $provider, $this->app['session.store']);

        if (method_exists($guard, 'setCookieJar')) {
            $guard->setCookieJar($this->app['cookie']);
        }

        if (method_exists($guard, 'setDispatcher')) {
            $guard->setDispatcher($this->app['events']);
        }

        if (method_exists($guard, 'setRequest')) {
            $guard->setRequest($this->app->refresh('request', $guard, 'setRequest'));
        }

        return $guard;
    }

所以最终是调用了SessionGuard的login方法来完成session部分的功能。

登录

展示表单的部分就不赘述了，这里我们直接看:

$this->post('login', 'AuthLoginController@login');

//LoginController.php
class LoginController extends Controller
{
    use AuthenticatesUsers;

    /**
     * Where to redirect users after login.
     *
     * @var string
     */
    protected $redirectTo = '/home';

    /**
     * Create a new controller instance.
     *
     * @return void
     */
    public function __construct()
    {
        $this->middleware('guest')->except('logout');
    }
}

他使用到了一个AuthenticatesUserstrait，里面有一个login方法，也就是我们要使用到的login了:

public function login(Request $request)
    {
        $this->validateLogin($request);

        if ($this->hasTooManyLoginAttempts($request)) {
            $this->fireLockoutEvent($request);

            return $this->sendLockoutResponse($request);
        }

        if ($this->attemptLogin($request)) {
            return $this->sendLoginResponse($request);
        }

        $this->incrementLoginAttempts($request);

        return $this->sendFailedLoginResponse($request);
    }

其实大部分和register的部分差不多，核心部分还是在于SessionGuard对象的获取，这里就不过多赘述了，不过值得一提的是，像Auth::check()等很多方法的使用，其实也会通过SessionGuard来完成，主要是通过:

public function __call($method, $parameters)
    {
        return $this->guard()->{$method}(...$parameters);
    }

public function check()
    {
        return ! is_null($this->user());
    }

来得以完成调度。