Table of Contents
General
The idea of ​​relying on injection
Service container
bind
make
Home Backend Development PHP Tutorial Related analysis of service containers and dependency injection in PHP

Related analysis of service containers and dependency injection in PHP

Jun 18, 2019 pm 03:32 PM
php dependency injection service container

Related analysis of service containers and dependency injection in PHP

Dependency Injection

When class A needs to depend on class B, that is to say, class B needs to be instantiated in class A When an object is used, if the functions in class B change, the places where class B is used in class A will also be modified, resulting in high coupling between class A and class B. The solution at this time is that class A should rely on the interface of class B and hand over the instantiation of specific classes to the outside.

Take the notification module commonly used in our business.

General

<?php

/**
 * 定义了一个消息类
 * Class Message 
 */

class  Message{

  public function seed()
  {
      return &#39;灰太狼准备吃羊&#39;;
  }

}

/*
 * 订单产生的时候 需要发送消息
 */
class Order{

    protected $messager = &#39;&#39;;

    function __construct()
    {
        $this->messager = new Message();
    }

    public function seed_msg()
    {
        return $this->messager->seed();
    }
}

$Order = new Order();
echo $Order->seed_msg();
Copy after login

The above code is our traditional way of writing. First, the class sent by the message. Then where we need to send a message, call the interface for sending the message. One day you need to add an interface for sending text messages to meet different needs. Then you will find that you need to make changes in the Message class. You also need to make modifications in the Order class. This seems very troublesome. At this time, the idea of ​​dependency injection came into being.

The idea of ​​relying on injection

<?php

/**
 * 为了约束我们先定义一个消息接口
 * Interface Message
 */

interface  Message{
  public function seed();
}

/**
 * 有一个发送邮件的类
 * Class SeedEmail
 */
class SeedEmail implements Message
{
    public function seed()
    {
        return  &#39;灰太狼发邮件给红太狼说要吃烤全羊&#39;;
    }
}

/** 
 *新增一个发送短信的类
 * Class SeedSMS
 */
class SeedSMS implements Message
{
    public function seed()
    {
        return  &#39;灰太狼发短信给红太狼说要吃烤全羊&#39;;
    }
}

/*
 * 订单产生的时候 需要发送消息
 */

class Order{

    protected $messager = &#39;&#39;;

    function __construct(Message $message)
    {
        $this->messager = $message;
    }

    public function seed_msg()
    {
        return $this->messager->seed();
    }

}

//我们需要发送邮件的时候
$message = new SeedEmail();
//将邮件发送对象作为参数传递给Order
$Order = new Order($message);
echo $Order->seed_msg();

echo "\n";

//我们需要发送短信的时候
$message = new SeedSMS();
$Order = new Order($message);
echo $Order->seed_msg();
Copy after login

The service container I understand is a factory that automatically generates classes.

Service container

<?php

/**
 * 为了约束我们先定义一个消息接口
 * Interface Message
 */
interface  Message{
    public function seed();
}

/**
 * 有一个发送邮件的类
 * Class SeedEmail
 */
class SeedEmail implements Message
{
    public function seed()
    {
        return  &#39;灰太狼发邮件给红太狼说要吃烤全羊&#39;;
    }
}

/** 
 *新增一个发送短信的类
 * Class SeedSMS
 */
class SeedSMS implements Message
{
    public function seed()
    {
        return  &#39;灰太狼发短信给红太狼说要吃烤全羊&#39;;
    }
}

/**
 * 这是一个简单的服务容器
 * Class Container
 */

class Container
{

    protected $binds;
 
    protected $instances;

    public function bind($abstract, $concrete)
    {
        if ($concrete instanceof Closure) {
            $this->binds[$abstract] = $concrete;
        } else {
            $this->instances[$abstract] = $concrete;
        }
    }

    public function make($abstract, $parameters = [])
    {
        if (isset($this->instances[$abstract])) {
            return $this->instances[$abstract];
        }
        array_unshift($parameters, $this);
        return call_user_func_array($this->binds[$abstract], $parameters);
    }
}

//创建一个消息工厂
$message = new  Container();

//将发送短信注册绑定到工厂里面
$message->bind('SMS',function (){
     return   new  SeedSMS();
});

//将发送邮件注册绑定到工厂
$message->bind('EMAIL',function (){
   return new  SeedEmail();
});

//需要发送短信的时候
$SMS  = $message->make('SMS');
echo $SMS->seed();

echo "\n";

$EMAIL  = $message->make('EMAIL');
echo $EMAIL->seed();
Copy after login

container is a simple service container with bind,makeTwo methods

bind is to bind the service object to the container.

make takes out the object from the container.

bind

In the bind method, you need to pass in a concrete. We can pass in an instance object or a closure function.
You can see that I am using a closure function. In fact, you can also write it like this

$sms = new  SeedSMS();
$message->bind('SMS',$sms);
Copy after login

The difference between this latter writing method and closure is that we need to instantiate the object first before we can proceed easily. Binding services. Closures only instantiate objects when we use this service. It can be seen that closures have many advantages.

make

The make method is the method to exit the container. It first determines whether there is a current and existing service object in the instances variable, and if so, returns it directly. If not, an object will be returned through call_user_func_array. For the use of call_user_func_array, you can view the use of call_user_func in
PHP

For more PHP related technical articles, please visitPHP Tutorialcolumn for learning!

The above is the detailed content of Related analysis of service containers and dependency injection in PHP. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

AI Hentai Generator

AI Hentai Generator

Generate AI Hentai for free.

Hot Article

R.E.P.O. Energy Crystals Explained and What They Do (Yellow Crystal)
2 weeks ago By 尊渡假赌尊渡假赌尊渡假赌
Repo: How To Revive Teammates
1 months ago By 尊渡假赌尊渡假赌尊渡假赌
Hello Kitty Island Adventure: How To Get Giant Seeds
4 weeks ago By 尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

CakePHP Project Configuration CakePHP Project Configuration Sep 10, 2024 pm 05:25 PM

In this chapter, we will understand the Environment Variables, General Configuration, Database Configuration and Email Configuration in CakePHP.

PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian PHP 8.4 Installation and Upgrade guide for Ubuntu and Debian Dec 24, 2024 pm 04:42 PM

PHP 8.4 brings several new features, security improvements, and performance improvements with healthy amounts of feature deprecations and removals. This guide explains how to install PHP 8.4 or upgrade to PHP 8.4 on Ubuntu, Debian, or their derivati

CakePHP Date and Time CakePHP Date and Time Sep 10, 2024 pm 05:27 PM

To work with date and time in cakephp4, we are going to make use of the available FrozenTime class.

CakePHP File upload CakePHP File upload Sep 10, 2024 pm 05:27 PM

To work on file upload we are going to use the form helper. Here, is an example for file upload.

CakePHP Routing CakePHP Routing Sep 10, 2024 pm 05:25 PM

In this chapter, we are going to learn the following topics related to routing ?

Discuss CakePHP Discuss CakePHP Sep 10, 2024 pm 05:28 PM

CakePHP is an open-source framework for PHP. It is intended to make developing, deploying and maintaining applications much easier. CakePHP is based on a MVC-like architecture that is both powerful and easy to grasp. Models, Views, and Controllers gu

How To Set Up Visual Studio Code (VS Code) for PHP Development How To Set Up Visual Studio Code (VS Code) for PHP Development Dec 20, 2024 am 11:31 AM

Visual Studio Code, also known as VS Code, is a free source code editor — or integrated development environment (IDE) — available for all major operating systems. With a large collection of extensions for many programming languages, VS Code can be c

CakePHP Creating Validators CakePHP Creating Validators Sep 10, 2024 pm 05:26 PM

Validator can be created by adding the following two lines in the controller.

See all articles