场景:

       laravel源码学习观摩, 选了一段分析一下，也遇到一些问题 mark一下

分析:

     发送重置密码的连接  App\Http\Controllers\Auth\ForgotPasswordController@sendResetLinkEmail

     发送这种连接之前 肯定是需要检查下填写的邮箱是不是自己网站的用户的, 但是这里面只有一个方法

     trait SendsPasswordResetEmails  代码如下:

      $response = $this->broker()->sendResetLink($request->only('email'));  处理邮件发送

       $this->broker是Password Facade 定义的 (调用自身的broker)  

                             先说结论 Illuminate\Auth\Passwords\PasswordBroker 实例                          

<?php

namespace Illuminate\Foundation\Auth;

use Illuminate\Http\Request;
use Illuminate\Support\Facades\Password;

trait SendsPasswordResetEmails
{
    /**
     * Display the form to request a password reset link.
     *
     * @return \Illuminate\Http\Response
     */
    public function showLinkRequestForm()
    {
        return view('');
    }

    /**
     * Send a reset link to the given user.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\RedirectResponse|\Illuminate\Http\JsonResponse
     */
    public function sendResetLinkEmail(Request $request)
    {
        $this->validateEmail($request);

        // We will send the password reset link to this user. Once we have attempted
        // to send the link, we will examine the response then see the message we
        // need to show to the user. Finally, we'll send out a proper response.
        $response = $this->broker()->sendResetLink( 
            $request->only('email')
        );

        return $response == Password::RESET_LINK_SENT
                    ? $this->sendResetLinkResponse($response)
                    : $this->sendResetLinkFailedResponse($request, $response);
    }

    /**
     * Validate the email for the given request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return void
     */
    protected function validateEmail(Request $request)
    {
        $this->validate($request, ['email' => 'required|email']);
    }

    /**
     * Get the response for a successful password reset link.
     *
     * @param  string  $response
     * @return \Illuminate\Http\RedirectResponse|\Illuminate\Http\JsonResponse
     */
    protected function sendResetLinkResponse($response)
    {
        return back()->with('status', trans($response));
    }

    /**
     * Get the response for a failed password reset link.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  string  $response
     * @return \Illuminate\Http\RedirectResponse|\Illuminate\Http\JsonResponse
     */
    protected function sendResetLinkFailedResponse(Request $request, $response)
    {
        return back()->withErrors(
            ['email' => trans($response)]
        );
    }

    /**
     * Get the broker to be used during password reset.
     *
     * @return \Illuminate\Contracts\Auth\PasswordBroker
     */
    public function broker()
    {
        return Password::broker();
    }
}

 而Password Facade  是这样定义 getFacadeAccessor ； 那么'auth.password'组件是在注册的呢     

Illuminate\Auth\Passwords\PasswordResetServiceProvider 

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

    而在PasswordResetServiceProvider 可以看到 'auth.password' 是  new PasswordBrokerManager($app); 

class PasswordResetServiceProvider extends ServiceProvider
{
    /**
     * Indicates if loading of the provider is deferred.
     *
     * @var bool
     */
    protected $defer = true;

    /**
     * Register the service provider.
     *
     * @return void
     */
    public function register()
    {
        $this->registerPasswordBroker();
    }

    /**
     * Register the password broker instance.
     *
     * @return void
     */
    protected function registerPasswordBroker()
    {
        $this->app->singleton('auth.password', function ($app) {
            return new PasswordBrokerManager($app);
        });

        $this->app->bind('auth.password.broker', function ($app) {
            return $app->make('auth.password')->broker();
        });
    }

    /**
     * Get the services provided by the provider.
     *
     * @return array
     */
    public function provides()
    {
        return ['auth.password', 'auth.password.broker'];
    }
}

        Illuminate\Auth\Passwords\PasswordBrokerManager 的broker 方法 Illuminate\Auth\Passwords\PasswordBroker

        实例  

<?php

namespace Illuminate\Auth\Passwords;

use Illuminate\Support\Str;
use InvalidArgumentException;
use Illuminate\Contracts\Auth\PasswordBrokerFactory as FactoryContract;

/**
 * @mixin \Illuminate\Contracts\Auth\PasswordBroker
 */
class PasswordBrokerManager implements FactoryContract
{
    /**
     * The application instance.
     *
     * @var \Illuminate\Foundation\Application
     */
    protected $app;

    /**
     * The array of created "drivers".
     *
     * @var array
     */
    protected $brokers = [];

    /**
     * Create a new PasswordBroker manager instance.
     *
     * @param  \Illuminate\Foundation\Application  $app
     * @return void
     */
    public function __construct($app)
    {
        $this->app = $app;
    }

    /**
     * Attempt to get the broker from the local cache.
     *
     * @param  string  $name
     * @return \Illuminate\Contracts\Auth\PasswordBroker
     */
    public function broker($name = null)
    {
        $name = $name ?: $this->getDefaultDriver();

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

    /**
     * Resolve the given broker.
     *
     * @param  string  $name
     * @return \Illuminate\Contracts\Auth\PasswordBroker
     *
     * @throws \InvalidArgumentException
     */
    protected function resolve($name)
    {
        $config = $this->getConfig($name);

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

        // The password broker uses a token repository to validate tokens and send user
        // password e-mails, as well as validating that password reset process as an
        // aggregate service of sorts providing a convenient interface for resets.
        return new PasswordBroker(
            $this->createTokenRepository($config),
            $this->app['auth']->createUserProvider($config['provider'] ?? null)
        );
    }

    /**
     * Create a token repository instance based on the given configuration.
     *
     * @param  array  $config
     * @return \Illuminate\Auth\Passwords\TokenRepositoryInterface
     */
    protected function createTokenRepository(array $config)
    {
        $key = $this->app['config']['app.key'];

        if (Str::startsWith($key, 'base64:')) {
            $key = base64_decode(substr($key, 7));
        }

        $connection = $config['connection'] ?? null;

        return new DatabaseTokenRepository(
            $this->app['db']->connection($connection),
            $this->app['hash'],
            $config['table'],
            $key,
            $config['expire']
        );
    }

    /**
     * Get the password broker configuration.
     *
     * @param  string  $name
     * @return array
     */
    protected function getConfig($name)
    {
        return $this->app['config']["auth.passwords.{$name}"];
    }

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

    /**
     * Set the default password broker name.
     *
     * @param  string  $name
     * @return void
     */
    public function setDefaultDriver($name)
    {
        $this->app['config']['auth.defaults.passwords'] = $name;
    }

    /**
     * Dynamically call the default driver instance.
     *
     * @param  string  $method
     * @param  array   $parameters
     * @return mixed
     */
    public function __call($method, $parameters)
    {
        return $this->broker()->{$method}(...$parameters);
    }
}