Contracts
Contracts其实就是倡导面向接口编程，来达到解耦的目的。而这些通用的接口已经由Laravel为你设计好了。就是这些Contracts.
那么Laravel如何知道我们需要使用哪个实现呢？
在Laravel默认的Contracts绑定中，在'Illuminate/Foundation/Application.PHP'有这样的定义:这就是绑定了默认的接口实现.
/**
* Register the core class aliases in the container.
*
* @return void
*/
public function registerCoreContainerAliases()
{
$aliases = [
'app' => ['Illuminate\Foundation\Application','Illuminate\Contracts\Container\Container','Illuminate\Contracts\Foundation\Application'],'auth' => 'Illuminate\Auth\AuthManager','auth.driver' => ['Illuminate\Auth\Guard','Illuminate\Contracts\Auth\Guard'],'auth.password.tokens' => 'Illuminate\Auth\Passwords\TokenRepositoryInterface','blade.compiler' => 'Illuminate\View\Compilers\BladeCompiler','cache' => ['Illuminate\Cache\CacheManager','Illuminate\Contracts\Cache\Factory'],'cache.store' => ['Illuminate\Cache\Repository','Illuminate\Contracts\Cache\Repository'],'config' => ['Illuminate\Config\Repository','Illuminate\Contracts\Config\Repository'],'cookie' => ['Illuminate\Cookie\CookieJar','Illuminate\Contracts\Cookie\Factory','Illuminate\Contracts\Cookie\QueueingFactory'],'encrypter' => ['Illuminate\Encryption\Encrypter','Illuminate\Contracts\Encryption\Encrypter'],'db' => 'Illuminate\Database\DatabaseManager','db.connection' => ['Illuminate\Database\Connection','Illuminate\Database\ConnectionInterface'],'events' => ['Illuminate\Events\Dispatcher','Illuminate\Contracts\Events\Dispatcher'],'files' => 'Illuminate\Filesystem\Filesystem','filesystem' => ['Illuminate\Filesystem\FilesystemManager','Illuminate\Contracts\Filesystem\Factory'],'filesystem.disk' => 'Illuminate\Contracts\Filesystem\Filesystem','filesystem.cloud' => 'Illuminate\Contracts\Filesystem\Cloud','hash' => 'Illuminate\Contracts\Hashing\Hasher','translator' => ['Illuminate\Translation\Translator','Symfony\Component\Translation\TranslatorInterface'],'log' => ['Illuminate\Log\Writer','Illuminate\Contracts\Logging\Log','Psr\Log\LoggerInterface'],'mailer' => ['Illuminate\Mail\Mailer','Illuminate\Contracts\Mail\Mailer','Illuminate\Contracts\Mail\MailQueue'],'auth.password' => ['Illuminate\Auth\Passwords\PasswordBroker','Illuminate\Contracts\Auth\PasswordBroker'],'queue' => ['Illuminate\Queue\QueueManager','Illuminate\Contracts\Queue\Factory','Illuminate\Contracts\Queue\Monitor'],'queue.connection' => 'Illuminate\Contracts\Queue\Queue','redirect' => 'Illuminate\Routing\Redirector','redis' => ['Illuminate\Redis\Database','Illuminate\Contracts\Redis\Database'],'request' => 'Illuminate\Http\Request','router' => ['Illuminate\Routing\Router','Illuminate\Contracts\Routing\Registrar'],'session' => 'Illuminate\Session\SessionManager','session.store' => ['Illuminate\Session\Store','Symfony\Component\HttpFoundation\Session\SessionInterface'],'url' => ['Illuminate\Routing\UrlGenerator','Illuminate\Contracts\Routing\UrlGenerator'],'validator' => ['Illuminate\Validation\Factory','Illuminate\Contracts\Validation\Factory'],'view' => ['Illuminate\View\Factory','Illuminate\Contracts\View\Factory'],];
在我们自定义的接口实现时，我们可以在ServiceProvider中使用进行绑定:
$this->app->bind('App\Contracts\EventPusher','App\Services\PusherEventPusher');
Facades
Facades 为应用程序的服务容器中可用的类提供了一个「静态」接口。Laravel 「facades」作为在服务容器内基类的「静态代理」。很难懂？
我们打开项目目录下的config/app.PHP，然后找到
/*
|--------------------------------------------------------------------------
| Class Aliases
|--------------------------------------------------------------------------
|
| This array of class aliases will be registered when this application
| is started. However,feel free to register as many as you wish as
| the aliases are "lazy" loaded so they don't hinder performance.
|
*/
'aliases' => [
'App' => Illuminate\Support\Facades\App::class,'Artisan' => Illuminate\Support\Facades\Artisan::class,'Auth' => Illuminate\Support\Facades\Auth::class,'Blade' => Illuminate\Support\Facades\Blade::class,'Bus' => Illuminate\Support\Facades\Bus::class,'Cache' => Illuminate\Support\Facades\Cache::class,'Config' => Illuminate\Support\Facades\Config::class,'Cookie' => Illuminate\Support\Facades\Cookie::class,'Crypt' => Illuminate\Support\Facades\Crypt::class,'DB' => Illuminate\Support\Facades\DB::class,'Eloquent' => Illuminate\Database\Eloquent\Model::class,'Event' => Illuminate\Support\Facades\Event::class,'File' => Illuminate\Support\Facades\File::class,'Gate' => Illuminate\Support\Facades\Gate::class,'Hash' => Illuminate\Support\Facades\Hash::class,'Input' => Illuminate\Support\Facades\Input::class,'Lang' => Illuminate\Support\Facades\Lang::class,'Log' => Illuminate\Support\Facades\Log::class,'Mail' => Illuminate\Support\Facades\Mail::class,'Password' => Illuminate\Support\Facades\Password::class,'Queue' => Illuminate\Support\Facades\Queue::class,'Redirect' => Illuminate\Support\Facades\Redirect::class,'Redis' => Illuminate\Support\Facades\Redis::class,'Request' => Illuminate\Support\Facades\Request::class,'Response' => Illuminate\Support\Facades\Response::class,'Route' => Illuminate\Support\Facades\Route::class,'Schema' => Illuminate\Support\Facades\Schema::class,'Session' => Illuminate\Support\Facades\Session::class,'Storage' => Illuminate\Support\Facades\Storage::class,'URL' => Illuminate\Support\Facades\URL::class,'Validator' => Illuminate\Support\Facades\Validator::class,'View' => Illuminate\Support\Facades\View::class,],
你是不是发现了什么？对，Facades其实就是在config/app.PHP中定义的一系列类的别名。只不过这些类都具有一个共同的特点，那就是继承基底 Illuminate\Support\Facades\Facade 类并实现一个方法：getFacadeAccessor返回名称。
自定义Facade
参考http://www.tutorialspoint.com/laravel/laravel_facades.htm
Step 1 −创建一个名为 TestFacadesServiceProvider的ServiceProvider,使用如下命令即可:
PHP artisan make:provider TestFacadesServiceProvider
Step 2 − 创建一个底层代理类，命名为“TestFacades.PHP” at “App/Test”.
App/Test/TestFacades.PHP
<?PHP namespace App\Test; class TestFacades{ public function testingFacades(){ echo "Testing the Facades in Laravel."; } } ?>
Step 3 − 创建一个 Facade 类 called “TestFacades.PHP” at “App/Test/Facades”.
App/Test/Facades/TestFacades.PHP
<?PHP namespace app\Test\Facades; use Illuminate\Support\Facades\Facade; class TestFacades extends Facade{ protected static function getFacadeAccessor() { return 'test'; } }
Step 4 −创建一个ServiceProviders类，名为“TestFacadesServiceProviders.PHP” at “App/Test/Facades”.
App/Providers/TestFacadesServiceProviders.PHP
<?PHP namespace App\Providers; use App; use Illuminate\Support\ServiceProvider; class TestFacadesServiceProvider extends ServiceProvider { public function boot() { // } public function register() { //可以这么绑定,这需要use App; // App::bind('test',function() { // return new \App\Test\TestFacades; // }); //也可以这么绑定，推荐。这个test对应于Facade的getFacadeAccessor返回值 $this->app->bind("test",function(){ return new MyFoo(); //给这个Facade返回一个代理实例。所有对Facade的调用都会被转发到该类对象下。 }); } }
Step 5 − 在config/app.PHP注册ServiceProvider类
Step 6 − 在config/app.PHP注册自定义Facade的别名
使用测试：
Add the following lines in app/Http/routes.PHP.
Route::get('/facadeex',function(){
return TestFacades::testingFacades();
});
Step 9 − Visit the following URL to test the Facade.
http://localhost:8000/facadeex去查看输出
更多学习内容请访问：
腾讯T3-T4标准精品PHP架构师教程目录大全，只要你看完保证薪资上升一个台阶（持续更新）
