About the principle of action parameter binding in some PHP frameworks

WBOY
Release: 2016-07-06 13:53:58
Original
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For example THINKPHP

<code>class xxController
{
    public function index($id,$age)
    {
        //这些参数是通过$_GET['id'],$_GET['age']来的
        
    }
}
//按PHP的实现方法大致应该是以下
$ctr = new xxController();
return $ctr->index(); //他这里怎么有知道应该传哪些参数呢?!

//本人愚钝,我想不是这样做的,那应该是怎么实现呢?!!请各位大神讲解一下其中的实现原理!</code>
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Reply content:

For example THINKPHP

<code>class xxController
{
    public function index($id,$age)
    {
        //这些参数是通过$_GET['id'],$_GET['age']来的
        
    }
}
//按PHP的实现方法大致应该是以下
$ctr = new xxController();
return $ctr->index(); //他这里怎么有知道应该传哪些参数呢?!

//本人愚钝,我想不是这样做的,那应该是怎么实现呢?!!请各位大神讲解一下其中的实现原理!</code>
Copy after login
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Reflection, the parameter list of the class method obtained through reflection. Then just match it up.

<code><?php
/**
 * 一个用于测试的类
 * Class TestController
 */
class TestController {
    /**
     * 嗯,著名的hello world
     * @param $name
     */
    public function helloWordAction($name)
    {
        echo "hello {$name}!".PHP_EOL;
    }
}

# 通过反射进行参数绑定调起类的方法
# @see http://php.net/manual/zh/book.reflection.php

# 方法,从路由获取的,类也是由路由获取的,这里意思一下就好了
$action = 'helloWordAction';
# 传进来的参数,从路由获取的
$paramsInput['name'] = 'toozy';

# 获取类的反射
$controllerReflection = new ReflectionClass(TestController::class);
# 不能实例化,就是不能new一个的话,这个游戏就玩不下去了啊
if (!$controllerReflection->isInstantiable()) {
    throw new RuntimeException("{$controllerReflection->getName()}不能被实例化");
}

# 获取对应方法的反射
if (!$controllerReflection->hasMethod($action)) {
    throw new RuntimeException("{$controllerReflection->getName()}没有指定的方法:{$action}");
}
$actionReflection = $controllerReflection->getMethod($action);
# 获取方法的参数的反射列表(多个参数反射组成的数组)
$paramReflectionList = $actionReflection->getParameters();
# 参数,用于action
$params = [];
# 循环参数反射
# 如果存在路由参数的名称和参数的名称一致,就压进params里面
# 如果存在默认值,就将默认值压进params里面
# 如果。。。没有如果了,异常
foreach ($paramReflectionList as $paramReflection) {
    # 是否存在同名字的路由参数
    if (isset($paramsInput[$paramReflection->getName()])) {
        $params[] = $paramsInput[$paramReflection->getName()];
        continue;
    }
    # 是否存在默认值
    if ($paramReflection->isDefaultValueAvailable()) {
        $params[] = $paramReflection->getDefaultValue();
        continue;
    }
    # 异常
    throw new RuntimeException(
        "{$controllerReflection->getName()}::{$actionReflection->getName()}的参数{$paramReflection->getName()}必须传值"
    );
}

# 调起
$actionReflection->invokeArgs($controllerReflection->newInstance(), $params);</code>
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Save as: reflection.php

<code>root@work:/media/sf_project/php-hello-world# php refrection.php 
hello toozy!</code>
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The framework in this case has a "route definition", and the client can only match the defined route, which includes path, method, and request parameters.
Take Laravel as an example:

<code>Route::get('api/article/{articleId}', 'ArticleController@articleDetail');

//...

ArticleController extends Controller
{
    public function articleDetail($articleId)
    {
        //...
    }
}</code>
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During the matching routing process, because the route defined contains the placeholder {articleId} in the agreed form, the routing module will match the URL containing articleId and obtain the parameter value and pass it to the action of the corresponding Controller.

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