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.
Important Points
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.