Yii2.0—Module

A module is an independent software unit, consisting of models, views, controllers and other supporting components. End users can access the controllers of installed modules in the application body. The module is treated as a small application body, which is different from the application body. The important thing is that modules cannot be deployed individually and must belong to an application subject.

Create module

The module is organized into a directory called [[yiibaseModule::basePath|base path]]. In this directory, there are subdirectories such as controllers, models, and views for corresponding controllers, models, views, and The rest of the code is very similar to the application. The following example shows the directory structure of a model:

forum/
    Module.php                   模块类文件
    controllers/                 包含控制器类文件
        DefaultController.php    default 控制器类文件
    models/                      包含模型类文件
    views/                       包含控制器视图文件和布局文件
        layouts/                 包含布局文件
        default/                 包含DefaultController控制器视图文件
            index.php            index视图文件

Module class

Each module has a module class that inherits [[yiibaseModule]], and this class file is placed directly in the module's [[yiibaseModule::basePath|base path] ] directory and can be loaded automatically. When a module is accessed, a unique instance of the module class is created similar to the application body instance. The module instance is used to help the code within the module share data and components.

The following example roughly defines a module class:

namespace app\modules\forum; class Module extends \yii\base\Module { public function init() { parent::init(); $this->params['foo'] = 'bar'; 
// ...  其他初始化代码 ... } }

If the init() method contains a lot of code to initialize module properties, they can be saved in the configuration and loaded using the following code in init():

public function init() { parent::init(); // 从config.php加载配置来初始化模块 \Yii::configure($this, require(__DIR__ . '/config.php')); }

config.php configuration file It may contain the following content, similar to the application main configuration.

<?php return [ &#39;components&#39; => [ // list of component configurations ], &#39;params&#39; => [ // list of parameters ], ];

Controllers in modules

When creating a module's controller, the convention is to place the controller class in the controllers sub-namespace of the module class namespace, which also means Place the controller class files in the controllers subdirectory in the module [[yiibaseModule::basePath|base path]] directory. For example, to create a post controller in the forum module in the previous section, you should declare the controller class as follows:

namespace app\modules\forum\controllers; use yii\web\Controller; class PostController extends Controller { // ... }

You can configure the [[yiibaseModule::controllerNamespace]] attribute to customize the namespace of the controller class. If some controllers No longer in this namespace, you can configure the [[yiibaseModule::controllerMap]] attribute to make them accessible, similar to what is done in the application body configuration.

Views in the module

The views should be placed in the views directory under the directory corresponding to [[yiibaseModule::basePath|base path]] of the module. The view files corresponding to the controllers in the module should be placed under the views/ControllerID directory. Where ControllerID corresponds to the controller ID. For example, if For example, assuming that the controller class is PostController, the directory corresponds to the views/post directory under the module [[yiibaseModule::basePath|base path]] directory.

Modules can specify layout, which is used in the module's controller view rendering. The layout file is placed in the views/layouts directory by default. You can configure the [[yiibaseModule::layout]] attribute to specify the layout name. If the layout attribute name is not configured, the application layout will be used by default.

Using modules

To use modules in an application, you only need to add the module to the list of [[yiibaseApplication::modules|modules]] attributes of the application body configuration. The application body configuration of the following code uses the forum module:

[ 'modules' => [ 'forum' => [ 'class' => 'app\modules\forum\Module', // ... 模块其他配置 ... ], ], ]

The

[[yiibaseApplication::modules|modules]] attribute uses a module configuration array. Each array key is the module ID, which identifies the unique module in the application. The value of the array is the configuration used to create the module.

Routing

Similar to accessing application controllers, routing is also used to address the controller in the module. The route for the controller in the module must start with the module ID, followed by the controller ID and operation ID. For example, assuming that the application uses a module named forum, the route forum/post/index represents the index operation of the post controller in the module. If the route only contains the module ID, the default [[yiibaseModule::defaultRoute]] attribute is used to determine the use. Which controller/action, that is, the routing forum may represent the default controller of the forum module.

Access module

In a module, you may often need to obtain an instance of a module class to access module ID, module parameters, module components, etc. You can use the following statement to obtain it:

$module = MyModuleClass::getInstance();

where MyModuleClass corresponds to the module class you want, The getInstance() method returns the currently requested module class instance. If the module is not requested, this method will return null. Note that there is no need to manually create a module class, because the manually created one is different from the one automatically created when Yii processes the request.

Supplement: When developing a module, you cannot assume that the module uses a fixed ID, because in the application or other modules, the module may correspond to any ID. In order to obtain the module ID, you should use the above code to obtain the module instance, and then Get the module ID through $module->id.

You can also access module instances using the following methods:

// 获取ID为 "forum" 的模块 $module = \Yii::$app->getModule('forum'); // 获取处理当前请求控制器所属的模块 $module = \Yii::$app->controller->module;

第一种方式仅在你知道模块ID的情况下有效，第二种方式在你知道处理请求的控制器下使用。

一旦获取到模块实例，可访问注册到模块的参数和组件，例如：

$maxPostCount = $module->params['maxPostCount'];

引导启动模块

有些模块在每个请求下都有运行， [[yii\debug\Module|debug]] 模块就是这种， 为此将这种模块加入到应用主体的 [[yii\base\Application::bootstrap|bootstrap]] 属性中。

例如，如下示例的应用主体配置会确保debug模块每次都被加载：

[ 'bootstrap' => [ 'debug', ], 'modules' => [ 'debug' => 'yii\debug\Module', ], ]

模块嵌套

模块可无限级嵌套，也就是说，模块可以包含另一个包含模块的模块，我们称前者为父模块，后者为子模块， 子模块必须在父模块的[[yii\base\Module::modules|modules]]属性中申明，例如：

namespace app\modules\forum; class Module extends \yii\base\Module { public function init() { parent::init(); $this->modules = [ 'admin' => [ 
// 此处应考虑使用一个更短的命名空间 'class' => 'app\modules\forum\modules\admin\Module', ], ]; } }

在嵌套模块中的控制器，它的路由应包含它所有祖先模块的ID，例如forum/admin/dashboard/index代表 在模块forum中子模块admin中dashboard控制器的index操作。

最佳实践

模块在大型项目中常备使用，这些项目的特性可分组，每个组包含一些强相关的特性， 每个特性组可以做成一个模块由特定的开发人员和开发组来开发和维护。

在特性组上，使用模块也是重用代码的好方式，一些常用特性，如用户管理，评论管理，可以开发成模块， 这样在相关项目中非常容易被重用。