laravel框架底层解析
本文参考陈昊《Laravel框架关键技术解析》,搭建一个属于自己的简化版服务容器。
其中涉及到反射、自动加载,还是需要去了解一下。
laravel服务容器
建立项目空文件夹(如 mylaravel)
添加
composer.json
,执行composer install
{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"license": "MIT",
"type": "project",
"autoload": {
"classmap": [
],
"psr-4": {
"App\\": "app/"
}
}
}
目的是为了学习、利用composer的自动加载。
文件路径如下所示
-
mylaravel
-
app
-
Traveller
Traveller.php
-
Visit
Leg.php
Visit.php
Container.php
Index.php
-
vendor
composer.json
-
简化版
Container.php
<?php
namespace App;
Class Container
{
protected $bindings = [];
/**
* 绑定接口和生成相应实例的回调函数
* @param $abstract 服务名称
* @param null $concreate 回调函数或名称
* @param bool $shared 是否为单例
*
*/
public function bind($abstract, $concrete = null, $shared = false)
{
if ( ! $concrete instanceof \Closure) {
// 如果提供的参数不是回调函数,则产生默认的回调函数
$concrete = $this->getClosure($abstract, $concrete);
}
$this->bindings[$abstract] = compact('concrete', 'shared');
}
//默认的回调函数
protected function getClosure($abstract, $concrete)
{
//生成实例的回调函数, $c一般为ioc容器对象
return function($c) use ($abstract, $concrete)
{
$method = ($abstract == $concrete) ? 'build' : 'make';
return $c->$method($concrete);
};
}
//生成实例对象,首先解决接口和要实例化类之间的依赖
public function make($abstract)
{
$concrete = $this->getConcrete($abstract);
if ($this->isBuildable($concrete, $abstract)) {
$object = $this->build($concrete);
} else {
$object = $this->make($concrete);
}
return $object;
}
protected function isBuildable($concrete, $abstract)
{
return $concrete === $abstract || $concrete instanceof \Closure;
}
//获取绑定的回调函数
protected function getConcrete($abstract)
{
if ( ! isset($this->bindings[$abstract]))
{
return $abstract;
}
return $this->bindings[$abstract]['concrete'];
}
//实例化对象
public function build($concrete)
{
if ($concrete instanceof \Closure) {
return $concrete($this);
}
$reflector = new \ReflectionClass($concrete);
if ( ! $reflector->isInstantiable()) {
echo $message = "Target [$concrete] is not instantiable.";
}
$constructor = $reflector->getConstructor();
if (is_null($constructor)) {
return new $concrete;
}
$dependencies = $constructor->getParameters();
$instances = $this->getDependencies($dependencies);
return $reflector->newInstanceArgs($instances);
}
protected function getDependencies($parameters)
{
$dependencies = [];
foreach ($parameters as $parameter)
{
$denpendency = $parameter->getClass();
if (is_null($denpendency)) {
$dependencies[] = NULL;
} else {
$dependencies[] = $this->resolveClass($parameter);
}
}
return (array) $dependencies;
}
protected function resolveClass(\ReflectionParameter $parameter)
{
return $this->make($parameter->getClass()->name);
}
}
Visit.php
接口
<?php
namespace App\Visit;
interface Visit
{
public function go();
}
Leg.php
接口的一种实现
<?php
namespace App\Visit;
Class Leg implements Visit
{
public function go()
{
echo "walk to tibet!";
}
}
Traveller.php
相当于Controller下的方法
<?php
namespace App\Traveller;
use App\Visit\Visit;
Class Traveller
{
protected $trafficTool;
//Visit是抽象类,index中将leg注入到了容器,取代了Visit
public function __construct(Visit $visit)
{
$this->trafficTool = $visit;
}
public function visitTibet()
{
$this->trafficTool->go();
}
}
Index.php
<?php
namespace App;
//调用composer的自动加载
require '../vendor/autoload.php';
Class Index
{
public function index()
{
//实例化ioc容器
$app = new Container();
//容器填充
$app->bind('App\Visit\Visit', '\App\Visit\Leg');
$app->bind('Traveller', '\App\Traveller\Traveller');
//通过容器实现依赖注入,完成类的实例化
$tra = $app->make("\App\Traveller\Traveller");
$tra->visitTibet();
}
}
$b = new Index;
$b->index();
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