Analysis of ThinkPHP5's _initialize() initialization method

This method is said in the official manual:

If your controller class inherits the \think\Controller class, you can define the controller initialization method _initialize, in the controller is executed first before the method is called. In fact, there are more than 5, it has also appeared in previous versions. Let’s talk to you about its implementation process.

Example

The following is an example given in the official manual:

namespace app\index\controller;

use think\Controller;

class Index extends Controller
{

    public function _initialize()
    {
        echo 'init<br/>';
    }

    public function hello()
    {
        return 'hello';
    }

    public function data()
    {
        return 'data';
    }
}

If you access

http://localhost/index.php/index/Index/hello

, it will output

init
hello

If you access

http://localhost/index.php/index/Index/data

will output

init
data

Analysis

Because the use must inherit the

class, plus this is initialization, so we first I thought of

in the \think\Controller class. Let’s take a look at the code: <pre class="brush:php;toolbar:false">/**      * 架构函数      * @param Request    $request     Request对象      * @access public      */     public function __construct(Request $request = null)     {         if (is_null($request)) {             $request = Request::instance();         }         $this-&gt;view    = View::instance(Config::get('template'), Config::get('view_replace_str'));         $this-&gt;request = $request;         // 控制器初始化         if (method_exists($this, '_initialize')) {             $this-&gt;_initialize();         }         // 前置操作方法         if ($this-&gt;beforeActionList) {             foreach ($this-&gt;beforeActionList as $method =&gt; $options) {                 is_numeric($method) ?                 $this-&gt;beforeAction($options) :                 $this-&gt;beforeAction($method, $options);             }         }     }</pre> If you are careful, you must have noticed that in the entire constructor, There is a comment for controller initialization, and the following code is the key to achieving this initialization: <pre class="brush:php;toolbar:false">// 控制器初始化 if (method_exists($this, '_initialize')) {     $this-&gt;_initialize(); }</pre> Has the truth emerged? !

In fact, when a child class inherits the parent class, it will naturally inherit the parent class's constructor without overriding the constructor. Correspondingly, it will be judged whether there is

Methods are executed if available. This is the so-called

principle. ExtensionIf the subclass inherits the parent class and rewrites the constructor method, pay attention to calling the parent class's

, otherwise it will not be used. The code is as follows:

public function __construct()
{
    parent::__construct();
    ...其他代码...
}

SummaryA simple little design, here is a brief analysis, I hope it will be helpful to everyone.

Link

Related manual page: