Readouble

Laravel 5.4 Service Container

Introduction

The Laravel service container is a powerful tool for managing class dependencies and performing dependency injection. Dependency injection is a fancy phrase that essentially means this: class dependencies are "injected" into the class via the constructor or, in some cases, "setter" methods.

Let's look at a simple example:

<?php

namespace App\Http\Controllers;

use App\User;
use App\Repositories\UserRepository;
use App\Http\Controllers\Controller;

class UserController extends Controller
{
    /**
     * The user repository implementation.
     *
     * @var UserRepository
     */
    protected $users;

    /**
     * Create a new controller instance.
     *
     * @param  UserRepository  $users
     * @return void
     */
    public function __construct(UserRepository $users)
    {
        $this->users = $users;
    }

    /**
     * Show the profile for the given user.
     *
     * @param  int  $id
     * @return Response
     */
    public function show($id)
    {
        $user = $this->users->find($id);

        return view('user.profile', ['user' => $user]);
    }
}

In this example, the UserController needs to retrieve users from a data source. So, we will inject a service that is able to retrieve users. In this context, our UserRepository most likely uses Eloquent to retrieve user information from the database. However, since the repository is injected, we are able to easily swap it out with another implementation. We are also able to easily "mock", or create a dummy implementation of the UserRepository when testing our application.

A deep understanding of the Laravel service container is essential to building a powerful, large application, as well as for contributing to the Laravel core itself.

Binding

Binding Basics

Almost all of your service container bindings will be registered within service providers, so most of these examples will demonstrate using the container in that context.

lightbulb">Tip!! There is no need to bind classes into the container if they do not depend on any interfaces. The container does not need to be instructed on how to build these objects, since it can automatically resolve these objects using reflection.

Simple Bindings

Within a service provider, you always have access to the container via the $this->app property. We can register a binding using the bind method, passing the class or interface name that we wish to register along with a Closure that returns an instance of the class:

$this->app->bind('HelpSpot\API', function ($app) {
    return new HelpSpot\API($app->make('HttpClient'));
});

Note that we receive the container itself as an argument to the resolver. We can then use the container to resolve sub-dependencies of the object we are building.

Binding A Singleton

The singleton method binds a class or interface into the container that should only be resolved one time. Once a singleton binding is resolved, the same object instance will be returned on subsequent calls into the container:

$this->app->singleton('HelpSpot\API', function ($app) {
    return new HelpSpot\API($app->make('HttpClient'));
});

Binding Instances

You may also bind an existing object instance into the container using the instance method. The given instance will always be returned on subsequent calls into the container:

$api = new HelpSpot\API(new HttpClient);

$this->app->instance('HelpSpot\API', $api);

Binding Primitives

Sometimes you may have a class that receives some injected classes, but also needs an injected primitive value such as an integer. You may easily use contextual binding to inject any value your class may need:

$this->app->when('App\Http\Controllers\UserController')
          ->needs('$variableName')
          ->give($value);

Binding Interfaces To Implementations

A very powerful feature of the service container is its ability to bind an interface to a given implementation. For example, let's assume we have an EventPusher interface and a RedisEventPusher implementation. Once we have coded our RedisEventPusher implementation of this interface, we can register it with the service container like so:

$this->app->bind(
    'App\Contracts\EventPusher',
    'App\Services\RedisEventPusher'
);

This statement tells the container that it should inject the RedisEventPusher when a class needs an implementation of EventPusher. Now we can type-hint the EventPusher interface in a constructor, or any other location where dependencies are injected by the service container:

use App\Contracts\EventPusher;

/**
 * Create a new class instance.
 *
 * @param  EventPusher  $pusher
 * @return void
 */
public function __construct(EventPusher $pusher)
{
    $this->pusher = $pusher;
}

Contextual Binding

Sometimes you may have two classes that utilize the same interface, but you wish to inject different implementations into each class. For example, two controllers may depend on different implementations of the Illuminate\Contracts\Filesystem\Filesystem contract. Laravel provides a simple, fluent interface for defining this behavior:

use Illuminate\Support\Facades\Storage;
use App\Http\Controllers\PhotoController;
use App\Http\Controllers\VideoController;
use Illuminate\Contracts\Filesystem\Filesystem;

$this->app->when(PhotoController::class)
          ->needs(Filesystem::class)
          ->give(function () {
              return Storage::disk('local');
          });

$this->app->when(VideoController::class)
          ->needs(Filesystem::class)
          ->give(function () {
              return Storage::disk('s3');
          });

Tagging

Occasionally, you may need to resolve all of a certain "category" of binding. For example, perhaps you are building a report aggregator that receives an array of many different Report interface implementations. After registering the Report implementations, you can assign them a tag using the tag method:

$this->app->bind('SpeedReport', function () {
    //
});

$this->app->bind('MemoryReport', function () {
    //
});

$this->app->tag(['SpeedReport', 'MemoryReport'], 'reports');

Once the services have been tagged, you may easily resolve them all via the tagged method:

$this->app->bind('ReportAggregator', function ($app) {
    return new ReportAggregator($app->tagged('reports'));
});

Resolving

The make Method

You may use the make method to resolve a class instance out of the container. The make method accepts the name of the class or interface you wish to resolve:

$api = $this->app->make('HelpSpot\API');

If you are in a location of your code that does not have access to the $app variable, you may use the global resolve helper:

$api = resolve('HelpSpot\API');

If some of your class' dependencies are not resolvable via the container, you may inject them by passing them as an associative array into the makeWith method:

$api = $this->app->makeWith('HelpSpot\API', ['id' => 1]);

Automatic Injection

Alternatively, and importantly, you may simply "type-hint" the dependency in the constructor of a class that is resolved by the container, including controllers, event listeners, queue jobs, middleware, and more. In practice, this is how most of your objects should be resolved by the container.

For example, you may type-hint a repository defined by your application in a controller's constructor. The repository will automatically be resolved and injected into the class:

<?php

namespace App\Http\Controllers;

use App\Users\Repository as UserRepository;

class UserController extends Controller
{
    /**
     * The user repository instance.
     */
    protected $users;

    /**
     * Create a new controller instance.
     *
     * @param  UserRepository  $users
     * @return void
     */
    public function __construct(UserRepository $users)
    {
        $this->users = $users;
    }

    /**
     * Show the user with the given ID.
     *
     * @param  int  $id
     * @return Response
     */
    public function show($id)
    {
        //
    }
}

Container Events

The service container fires an event each time it resolves an object. You may listen to this event using the resolving method:

$this->app->resolving(function ($object, $app) {
    // Called when container resolves object of any type...
});

$this->app->resolving(HelpSpot\API::class, function ($api, $app) {
    // Called when container resolves objects of type "HelpSpot\API"...
});

As you can see, the object being resolved will be passed to the callback, allowing you to set any additional properties on the object before it is given to its consumer.

章選択

Official Packages

設定

明暗テーマ
light_mode
dark_mode
brightness_auto システム設定に合わせる
テーマ選択
photo_size_select_actual デフォルト
photo_size_select_actual モノクローム(白黒)
photo_size_select_actual Solarized風
photo_size_select_actual GitHub風(青ベース)
photo_size_select_actual Viva(黄緑ベース)
photo_size_select_actual Happy(紫ベース)
photo_size_select_actual Mint(緑ベース)
コードハイライトテーマ選択

明暗テーマごとに、コードハイライトのテーマを指定できます。

テーマ配色確認
スクリーン表示幅
640px
80%
90%
100%

768px以上の幅があるときのドキュメント部分表示幅です。

インデント
無し
1rem
2rem
3rem
原文確認
原文を全行表示
原文を一行ずつ表示
使用しない

※ 段落末のEボタンへカーソルオンで原文をPopupします。

Diff表示形式
色分けのみで区別
行頭の±で区別
削除線と追記で区別

※ [tl!…]形式の挿入削除行の表示形式です。

テストコード表示
両コード表示
Pestのみ表示
PHPUnitのみ表示
OS表示
全OS表示
macOSのみ表示
windowsのみ表示
linuxのみ表示
和文変換

対象文字列と置換文字列を半角スペースで区切ってください。(最大5組各10文字まで)

本文フォント

総称名以外はCSSと同様に、"〜"でエスケープしてください。

コードフォント

総称名以外はCSSと同様に、"〜"でエスケープしてください。

保存内容リセット

localStrageに保存してある設定項目をすべて削除し、デフォルト状態へ戻します。

ヘッダー項目移動

キーボード操作