A module is an entity that has its own models, views, controllers, and possibly other modules. It is practically an application inside the application.
Step 1 − Create a folder called modules inside your project root. Inside the modules folder, create a folder named hello. This will be the basic folder for our Hello module.
Step 2 − Inside the hello folder, create a file Hello.php with the following code.
<?php namespace app\modules\hello; class Hello extends \yii\base\Module { public function init() { parent::init(); } } ?>
We have just created a module class. This should be located under the module's base path. Every time a module is accessed, an instance of the correspondent module class is created. The init() function is for initializing the module's properties.
Step 3 − Now, add two more directories inside the hello folder − controllers and views. Add a CustomController.php file to the controller’s folder.
<?php namespace app\modules\hello\controllers; use yii\web\Controller; class CustomController extends Controller { public function actionGreet() { return $this->render('greet'); } } ?>
When creating a module, a convention is to put the controller classes into the controller’s directory of the module's base path. We have just defined the actionGreet function, that just returns a greet view.
Views in the module should be put in the views folder of the module's base path. If views are rendered by a controller, they should be located in the folder corresponding to the controllerID. Add custom folder to the views folder.
Step 4 − Inside the custom directory, create a file called greet.php with the following code.
<h1>Hello world from custom module!</h1>
We have just created a View for our actionGreet. To use this newly created module, we should configure the application. We should add our module to the modules property of the application.
Step 5 − Modify the config/web.php file.
<?php $params = require(__DIR__ . '/params.php'); $config = [ 'id' => 'basic', 'basePath' => dirname(__DIR__), 'bootstrap' => ['log'], 'components' => [ 'request' => [ // !!! insert a secret key in the following (if it is empty) - this is //required by cookie validation 'cookieValidationKey' => 'ymoaYrebZHa8gURuolioHGlK8fLXCKjO', ], 'cache' => [ 'class' => 'yii\caching\FileCache', ], 'user' => [ 'identityClass' => 'app\models\User', 'enableAutoLogin' => true, ], 'errorHandler' => [ 'errorAction' => 'site/error', ], 'mailer' => [ 'class' => 'yii\swiftmailer\Mailer', // send all mails to a file by default. You have to set // 'useFileTransport' to false and configure a transport // for the mailer to send real emails. 'useFileTransport' => true, ], 'log' => [ 'traceLevel' => YII_DEBUG ? 3 : 0, 'targets' => [ [ 'class' => 'yii\log\FileTarget', 'levels' => ['error', 'warning'], ], ], ], 'db' => require(__DIR__ . '/db.php'), ], 'modules' => [ 'hello' => [ 'class' => 'app\modules\hello\Hello', ], ], 'params' => $params, ]; if (YII_ENV_DEV) { // configuration adjustments for 'dev' environment $config['bootstrap'][] = 'debug'; $config['modules']['debug'] = [ 'class' => 'yii\debug\Module', ]; $config['bootstrap'][] = 'gii'; $config['modules']['gii'] = [ 'class' => 'yii\gii\Module', ]; } return $config; ?>
A route for a module's controller must begin with the module ID followed by the controller ID and action ID.
Step 6 − To run the actionGreet in our application, we should use the following route.
hello/custom/greet
Where hello is a module ID, custom is a controller ID and greet is an action ID.
Step 7 − Now, type http://localhost:8080/index.php?r=hello/custom/greet and you will see the following output.
Modules should −
Be used in large applications. You should divide its features into several groups. Each feature group can be developed as a module.
Be reusable. Some commonly used features, as SEO management or blog management, can be developed as modules, so that you can easily reuse them in future projects.