展開文件目錄

Contracts

Introduction

Laravel's "contracts" are a set of interfaces that define the core services provided by the framework. For example, an Illuminate\Contracts\Queue\Queue contract defines the methods needed for queueing jobs, while the Illuminate\Contracts\Mail\Mailer contract defines the methods needed for sending e-mail.

Each contract has a corresponding implementation provided by the framework. For example, Laravel provides a queue implementation with a variety of drivers, and a mailer implementation that is powered by Symfony Mailer.

All of the Laravel contracts live in their own GitHub repository. This provides a quick reference point for all available contracts, as well as a single, decoupled package that may be utilized when building packages that interact with Laravel services.

Contracts Vs. Facades

Laravel's facades and helper functions provide a simple way of utilizing Laravel's services without needing to type-hint and resolve contracts out of the service container. In most cases, each facade has an equivalent contract.

Unlike facades, which do not require you to require them in your class' constructor, contracts allow you to define explicit dependencies for your classes. Some developers prefer to explicitly define their dependencies in this way and therefore prefer to use contracts, while other developers enjoy the convenience of facades. In general, most applications can use facades without issue during development.

When To Use Contracts

The decision to use contracts or facades will come down to personal taste and the tastes of your development team. Both contracts and facades can be used to create robust, well-tested Laravel applications. Contracts and facades are not mutually exclusive. Some parts of your applications may use facades while others depend on contracts. As long as you are keeping your class' responsibilities focused, you will notice very few practical differences between using contracts and facades.

In general, most applications can use facades without issue during development. If you are building a package that integrates with multiple PHP frameworks you may wish to use the illuminate/contracts package to define your integration with Laravel's services without the need to require Laravel's concrete implementations in your package's composer.json file.

How To Use Contracts

So, how do you get an implementation of a contract? It's actually quite simple.

Many types of classes in Laravel are resolved through the service container, including controllers, event listeners, middleware, queued jobs, and even route closures. So, to get an implementation of a contract, you can just "type-hint" the interface in the constructor of the class being resolved.

For example, take a look at this event listener:

<?php

namespace App\Listeners;

use App\Events\OrderWasPlaced;
use App\Models\User;
use Illuminate\Contracts\Redis\Factory;

class CacheOrderInformation
{
    /**
     * The Redis factory implementation.
     *
     * @var \Illuminate\Contracts\Redis\Factory
     */
    protected $redis;

    /**
     * Create a new event handler instance.
     *
     * @param  \Illuminate\Contracts\Redis\Factory  $redis
     * @return void
     */
    public function __construct(Factory $redis)
    {
        $this->redis = $redis;
    }

    /**
     * Handle the event.
     *
     * @param  \App\Events\OrderWasPlaced  $event
     * @return void
     */
    public function handle(OrderWasPlaced $event)
    {
        //
    }
}

When the event listener is resolved, the service container will read the type-hints on the constructor of the class, and inject the appropriate value. To learn more about registering things in the service container, check out its documentation.

Contract Reference

This table provides a quick reference to all of the Laravel contracts and their equivalent facades:

Contract References Facade
Illuminate\Contracts\Auth\Access\Authorizable   
Illuminate\Contracts\Auth\Access\Gate Gate
Illuminate\Contracts\Auth\Authenticatable   
Illuminate\Contracts\Auth\CanResetPassword  
Illuminate\Contracts\Auth\Factory Auth
Illuminate\Contracts\Auth\Guard Auth::guard()
Illuminate\Contracts\Auth\PasswordBroker Password::broker()
Illuminate\Contracts\Auth\PasswordBrokerFactory Password
Illuminate\Contracts\Auth\StatefulGuard  
Illuminate\Contracts\Auth\SupportsBasicAuth  
Illuminate\Contracts\Auth\UserProvider  
Illuminate\Contracts\Bus\Dispatcher Bus
Illuminate\Contracts\Bus\QueueingDispatcher Bus::dispatchToQueue()
Illuminate\Contracts\Broadcasting\Factory Broadcast
Illuminate\Contracts\Broadcasting\Broadcaster Broadcast::connection()
Illuminate\Contracts\Broadcasting\ShouldBroadcast  
Illuminate\Contracts\Broadcasting\ShouldBroadcastNow  
Illuminate\Contracts\Cache\Factory Cache
Illuminate\Contracts\Cache\Lock  
Illuminate\Contracts\Cache\LockProvider  
Illuminate\Contracts\Cache\Repository Cache::driver()
Illuminate\Contracts\Cache\Store  
Illuminate\Contracts\Config\Repository Config
Illuminate\Contracts\Console\Application  
Illuminate\Contracts\Console\Kernel Artisan
Illuminate\Contracts\Container\Container App
Illuminate\Contracts\Cookie\Factory Cookie
Illuminate\Contracts\Cookie\QueueingFactory Cookie::queue()
Illuminate\Contracts\Database\ModelIdentifier  
Illuminate\Contracts\Debug\ExceptionHandler  
Illuminate\Contracts\Encryption\Encrypter Crypt
Illuminate\Contracts\Events\Dispatcher Event
Illuminate\Contracts\Filesystem\Cloud Storage::cloud()
Illuminate\Contracts\Filesystem\Factory Storage
Illuminate\Contracts\Filesystem\Filesystem Storage::disk()
Illuminate\Contracts\Foundation\Application App
Illuminate\Contracts\Hashing\Hasher Hash
Illuminate\Contracts\Http\Kernel  
Illuminate\Contracts\Mail\MailQueue Mail::queue()
Illuminate\Contracts\Mail\Mailable  
Illuminate\Contracts\Mail\Mailer Mail
Illuminate\Contracts\Notifications\Dispatcher Notification
Illuminate\Contracts\Notifications\Factory Notification
Illuminate\Contracts\Pagination\LengthAwarePaginator  
Illuminate\Contracts\Pagination\Paginator  
Illuminate\Contracts\Pipeline\Hub  
Illuminate\Contracts\Pipeline\Pipeline  
Illuminate\Contracts\Queue\EntityResolver  
Illuminate\Contracts\Queue\Factory Queue
Illuminate\Contracts\Queue\Job  
Illuminate\Contracts\Queue\Monitor Queue
Illuminate\Contracts\Queue\Queue Queue::connection()
Illuminate\Contracts\Queue\QueueableCollection  
Illuminate\Contracts\Queue\QueueableEntity  
Illuminate\Contracts\Queue\ShouldQueue  
Illuminate\Contracts\Redis\Factory Redis
Illuminate\Contracts\Routing\BindingRegistrar Route
Illuminate\Contracts\Routing\Registrar Route
Illuminate\Contracts\Routing\ResponseFactory Response
Illuminate\Contracts\Routing\UrlGenerator URL
Illuminate\Contracts\Routing\UrlRoutable  
Illuminate\Contracts\Session\Session Session::driver()
Illuminate\Contracts\Support\Arrayable  
Illuminate\Contracts\Support\Htmlable  
Illuminate\Contracts\Support\Jsonable  
Illuminate\Contracts\Support\MessageBag  
Illuminate\Contracts\Support\MessageProvider  
Illuminate\Contracts\Support\Renderable  
Illuminate\Contracts\Support\Responsable  
Illuminate\Contracts\Translation\Loader  
Illuminate\Contracts\Translation\Translator Lang
Illuminate\Contracts\Validation\Factory Validator
Illuminate\Contracts\Validation\ImplicitRule  
Illuminate\Contracts\Validation\Rule  
Illuminate\Contracts\Validation\ValidatesWhenResolved  
Illuminate\Contracts\Validation\Validator Validator::make()
Illuminate\Contracts\View\Engine  
Illuminate\Contracts\View\Factory View
Illuminate\Contracts\View\View View::make()