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.
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/** * Register the core class aliases in the container. * * @return void */ public function registerCoreContainerAliases() { $aliases = [ 'app' => ['IlluminateFoundationApplication', 'IlluminateContractsContainerContainer', 'IlluminateContractsFoundationApplication'], 'auth' => 'IlluminateAuthAuthManager', 'auth.driver' => ['IlluminateAuthGuard', 'IlluminateContractsAuthGuard'], 'auth.password.tokens' => 'IlluminateAuthPasswordsTokenRepositoryInterface', 'blade.compiler' => 'IlluminateViewCompilersBladeCompiler', 'cache' => ['IlluminateCacheCacheManager', 'IlluminateContractsCacheFactory'], 'cache.store' => ['IlluminateCacheRepository', 'IlluminateContractsCacheRepository'], 'config' => ['IlluminateConfigRepository', 'IlluminateContractsConfigRepository'], 'cookie' => ['IlluminateCookieCookieJar', 'IlluminateContractsCookieFactory', 'IlluminateContractsCookieQueueingFactory'], 'encrypter' => ['IlluminateEncryptionEncrypter', 'IlluminateContractsEncryptionEncrypter'], 'db' => 'IlluminateDatabaseDatabaseManager', 'db.connection' => ['IlluminateDatabaseConnection', 'IlluminateDatabaseConnectionInterface'], 'events' => ['IlluminateEventsDispatcher', 'IlluminateContractsEventsDispatcher'], 'files' => 'IlluminateFilesystemFilesystem', 'filesystem' => ['IlluminateFilesystemFilesystemManager', 'IlluminateContractsFilesystemFactory'], 'filesystem.disk' => 'IlluminateContractsFilesystemFilesystem', 'filesystem.cloud' => 'IlluminateContractsFilesystemCloud', 'hash' => 'IlluminateContractsHashingHasher', 'translator' => ['IlluminateTranslationTranslator', 'SymfonyComponentTranslationTranslatorInterface'], 'log' => ['IlluminateLogWriter', 'IlluminateContractsLoggingLog', 'PsrLogLoggerInterface'], 'mailer' => ['IlluminateMailMailer', 'IlluminateContractsMailMailer', 'IlluminateContractsMailMailQueue'], 'auth.password' => ['IlluminateAuthPasswordsPasswordBroker', 'IlluminateContractsAuthPasswordBroker'], 'queue' => ['IlluminateQueueQueueManager', 'IlluminateContractsQueueFactory', 'IlluminateContractsQueueMonitor'], 'queue.connection' => 'IlluminateContractsQueueQueue', 'redirect' => 'IlluminateRoutingRedirector', 'redis' => ['IlluminateRedisDatabase', 'IlluminateContractsRedisDatabase'], 'request' => 'IlluminateHttpRequest', 'router' => ['IlluminateRoutingRouter', 'IlluminateContractsRoutingRegistrar'], 'session' => 'IlluminateSessionSessionManager', 'session.store' => ['IlluminateSessionStore', 'SymfonyComponentHttpFoundationSessionSessionInterface'], 'url' => ['IlluminateRoutingUrlGenerator', 'IlluminateContractsRoutingUrlGenerator'], 'validator' => ['IlluminateValidationFactory', 'IlluminateContractsValidationFactory'], 'view' => ['IlluminateViewFactory', 'IlluminateContractsViewFactory'], ];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('AppContractsEventPusher', 'AppServicesPusherEventPusher');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' => IlluminateSupportFacadesApp::class, 'Artisan' => IlluminateSupportFacadesArtisan::class, 'Auth' => IlluminateSupportFacadesAuth::class, 'Blade' => IlluminateSupportFacadesBlade::class, 'Bus' => IlluminateSupportFacadesBus::class, 'Cache' => IlluminateSupportFacadesCache::class, 'Config' => IlluminateSupportFacadesConfig::class, 'Cookie' => IlluminateSupportFacadesCookie::class, 'Crypt' => IlluminateSupportFacadesCrypt::class, 'DB' => IlluminateSupportFacadesDB::class, 'Eloquent' => IlluminateDatabaseEloquentModel::class, 'Event' => IlluminateSupportFacadesEvent::class, 'File' => IlluminateSupportFacadesFile::class, 'Gate' => IlluminateSupportFacadesGate::class, 'Hash' => IlluminateSupportFacadesHash::class, 'Input' => IlluminateSupportFacadesInput::class, 'Lang' => IlluminateSupportFacadesLang::class, 'Log' => IlluminateSupportFacadesLog::class, 'Mail' => IlluminateSupportFacadesMail::class, 'Password' => IlluminateSupportFacadesPassword::class, 'Queue' => IlluminateSupportFacadesQueue::class, 'Redirect' => IlluminateSupportFacadesRedirect::class, 'Redis' => IlluminateSupportFacadesRedis::class, 'Request' => IlluminateSupportFacadesRequest::class, 'Response' => IlluminateSupportFacadesResponse::class, 'Route' => IlluminateSupportFacadesRoute::class, 'Schema' => IlluminateSupportFacadesSchema::class, 'Session' => IlluminateSupportFacadesSession::class, 'Storage' => IlluminateSupportFacadesStorage::class, 'URL' => IlluminateSupportFacadesURL::class, 'Validator' => IlluminateSupportFacadesValidator::class, 'View' => IlluminateSupportFacadesView::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 IlluminateSupportFacadesFacade 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
<?phpnamespace AppTest;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
<?phpnamespace appTestFacades;use IlluminateSupportFacadesFacade;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
<?phpnamespace AppProviders;use App;use IlluminateSupportServiceProvider;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 AppTestTestFacades; // }); //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
