YII Frame Work Examples

YII First Example

After installing Yii, you can develop an application that can be accessed via URL http://hostname/basic/web/index.php or http://hostname/index.php depending upon your configuration.

We'll run a basic example of Hello World on Yii2.

Step1 Declaring action in controllers

We are creating an action called example. This action will read a message parameter from the request and will display that message.

Action is always declared in the Controllers file. Here, we are not creating a new file and is declaring this action in the existing SiteController.php.

Following is the starting code in SiteController.php file.

1. <?php   
2. namespace frontend\controllers;   
3.   
4. use Yii;   
5. use yii\base\InvalidParamException;   
6. use yii\web\BadRequestHttpException;   
7. use yii\web\Controller;   
8. use yii\filters\VerbFilter;   
9. use yii\filters\AccessControl;   
10. use common\models\LoginForm;   
11. use frontend\models\PasswordResetRequestForm;   
12. use frontend\models\ResetPasswordForm;   
13. use frontend\models\SignupForm;   
14. use frontend\models\ContactForm;   
15.   
16. /**  
17.  * Site controller  
18.  */   
19. class SiteController extends Controller   
20. {   
21.     /**  
22.      * @inheritdoc  
23.      */   
24.   
25.     public function actionExample($message = 'Hello')   
26.     {   
27.         return $this->render('example', ['message' => $message]);   
28.     }  

Look at the above code, example action is defined as a method named actionExample. Prefix action is used to differentiate action methods from non-action methods. Name after the prefix action denotes the action's ID.

Here we're taking a parameter $message, whose value is "Hello". If a request is sent with a message parameter in the URL with a different value say "Hyii", then this value will be displayed in the output. If no message parameter request is made in the URL, then "Hello" will be printed.

Function render() is called to display view file named example.php. This result will be displayed to the end user in the browser.

Step1 Creating View file

View folder basically contains the response content which will be delivered to the user on their request. In this example, we have created a file named example.php in the view/site folder.

Following is the code of example.php file.

1. <?php   
2.                     use yii\helpers\Html;   
3.                     ?>   
4.                     <?= Html::encode($message) ?>  

Look at the above code, the message parameter is HTML encoded before being printed to prevent from XSS attack.

Step1 Running on Browser

Access the page with the following URL:

http://localhost/hello/frontend/web/index.php?r=site%2Fexample&message=Hello+World

output is shown below.

Look at the above snapshot, output displays Hello World. In the URL, we have requested for message parameter.

If we'll omit the message parameter in the URL, then our URL will be:

http://localhost/hello/frontend/web/index.php?r=site%2Fexample

and our Output will be only "Hello".

In the URL, we have mentioned an r parameter. This r denotes to route. It's format is ControllerID/AtionID. In this example route denotes site/example.

What is Gii

Gii is an automatic code generation tool introduced in Yii 2.0. Code generation in Gii is quiet easy as filling the right information as per the instructions.

---

Starting Gii

By default, Gii is always enabled in the developing mode due to following code in the entry script web/index.php file in Yii:

defined('YII_ENV') or define('YII_ENV', 'dev');

http://localhost/advanced2/frontend/web/index.php?r=gii

This is the Gii output. From here you can generate your codes automatically.

Yii CRUD

Yii provides a gii tool which is a code generator tool. It gives you the generated code for CRUD. We'll learn how to generate CRUD with gii.

A simple example is shown here to generate a crud. We have named the Yii2 folder as crud. And our table name is employees.

Step 1 Open Gii

In the browser, type the following, http://localhost/crud/frontend/web/index.php?r=gii

Step 2 Generate Model

Look at the above snapshot, enter the table name which is employees in our case. Employees model class will be generated. Scroll down the page and click on Preview button.

Look at the above snpashot, click on Generate button to generate the code.

You'll see a successfull message as shown above.

---

Step 2 Generate CRUD

Look at the above snapshot,

In Model class, file Employees with the path frontend\models\Employees is generated.

In Search Model class, file EmployeesSearch with the path frontend\controllers\EmployeesSearch is generated.

In Controller class, file EmployeesController with the path @frontend\views\Employees is generated.

Click on Preview button to check for error. If no error is there, click on Generate button to generaate the code. Again you'll get a succesfull message for code generation.

Now our CRUD has been succesfully generated. To check it, run it on browser with the URL http://localhost/crud/frontend/web/index.php?r=employees/

Look at the above snapshot, Employees is our table name and you can search an entry from this table.

To insert values in the table click on Create Employees button. Following page will appear.

Fill the details above, and click on Create button. Data will be inserted in the table employees.

Look at the above snapshot, we have filled some entries in the table. Here you can see the icons to View, Update and Delete.

On clicking View icon, following page containing John's information will appear.

On clicking Update icon, following page containing John's information will appear where you can edit anything. Click on Update button after making changes.

On clicking Delete icon, following box will appear asking you to delete it or not.

---

Generated Code

In controllers, file EmployeesController.php will have the following code.

1. <?php   
2.   
3. namespace frontend\controllers;   
4.   
5. use Yii;   
6. use frontend\models\Employees;   
7. use frontend\models\EmployeesSearch;   
8. use yii\web\Controller;   
9. use yii\web\NotFoundHttpException;   
10. use yii\filters\VerbFilter;   
11.   
12. /**  
13.  * EmployeesController implements the CRUD actions for Employees model.  
14.  */   
15. class EmployeesController extends Controller   
16. {   
17.     /**  
18.      * @inheritdoc  
19.      */   
20.     public function behaviors()   
21.     {   
22.         return [   
23.             'verbs' => [   
24.                 'class' => VerbFilter::className(),   
25.  'actions' => [   
26.                     'delete' => ['POST'],   
27.                 ],   
28.             ],   
29.         ];   
30.     }   
31.   
32.     /**  
33.      * Lists all Employees models.  
34.      * @return mixed  
35.      */   
36.     public function actionIndex()   
37.     {   
38.         $searchModel = new EmployeesSearch();   
39.         $dataProvider = $searchModel->search(Yii::$app->request->queryParams);   
40.   
41.         return $this->render('index', [   
42.             'searchModel' => $searchModel,   
43.             'dataProvider' => $dataProvider,   
44.         ]);   
45.     }   
46.   
47.     /**  
48.      * Displays a single Employees model.  
49.      * @param integer $id  
50.      * @return mixed  
51.      */   
52.     public function actionView($id)   
53.     {   
54.         return $this->render('view', [   
55.             'model' => $this->findModel($id),   
56.         ]);   
57.     }   
58.   
59.     /**  
60.      * Creates a new Employees model.  
61.      * If creation is successful, the browser will be redirected to the 'view' page.  
62.      * @return mixed  
63.      */   
64.     public function actionCreate()   
65.     {   
66.         $model = new Employees();   
67.   
68.         if ($model->load(Yii::$app->request->post()) && $model->save()) {   
69.             return $this->redirect(['view', 'id' => $model->id]);   
70.         } else {   
71.             return $this->render('create', [   
72.                 'model' => $model,   
73.             ]);   
74.         }   
75.     }   
76.               
77. /**  
78.      * Updates an existing Employees model.  
79.      * If update is successful, the browser will be redirected to the 'view' page.  
80.      * @param integer $id  
81.      * @return mixed  
82.      */   
83.     public function actionUpdate($id)   
84.     {   
85.         $model = $this->findModel($id);   
86.   
87.         if ($model->load(Yii::$app->request->post()) && $model->save()) {   
88.             return $this->redirect(['view', 'id' => $model->id]);   
89.         } else {   
90.             return $this->render('update', [   
91.                 'model' => $model,   
92.             ]);   
93.         }   
94.     }   
95.   
96.     /**  
97.      * Deletes an existing Employees model.  
98.      * If deletion is successful, the browser will be redirected to the 'index' page.  
99.      * @param integer $id  
100.      * @return mixed  
101.      */   
102.     public function actionDelete($id)   
103.     {   
104.         $this->findModel($id)->delete();   
105.     return $this->redirect(['index']);   
106.     }   
107.   
108.     /**  
109.      * Finds the Employees model based on its primary key value.  
110.      * If the model is not found, a 404 HTTP exception will be thrown.  
111.      * @param integer $id  
112.      * @return Employees the loaded model  
113.      * @throws NotFoundHttpException if the model cannot be found  
114.      */   
115.     protected function findModel($id)   
116.     {   
117.         if (($model = Employees::findOne($id)) !== null) {   
118.             return $model;   
119.         } else {   
120.             throw new NotFoundHttpException('The requested page does not exist.');   
121.         }   
122.     }   
123. }    

In models, file Employees.php will have the following code.

1. <?php   
2.   
3. namespace frontend\models;   
4.   
5. use Yii;   
6.   
7. /**  
8.  * This is the model class for table "employees".  
9.  *  
10.  * @property integer $id  
11.  * @property string $name  
12.  * @property string $designation  
13.  * @property integer $contact  
14.  * @property string $email  
15.  */   
16. class Employees extends \yii\db\ActiveRecord   
17. {   
18.     /**  
19.      * @inheritdoc  
20.      */   
21.     public static function tableName()   
22.     {   
23.         return 'employees';   
24.     }   
25.   
26.     /**  
27.      * @inheritdoc  
28.      */   
29.     public function rules()   
30.     {   
31.         return [   
32.             [['name', 'designation', 'contact', 'email'], 'required'],   
33.             [['contact'], 'integer'],   
34.             [['name'], 'string', 'max' => 20],   
35.             [['designation'], 'string', 'max' => 50],   
36.             [['email'], 'string', 'max' => 80],   
37.         ];   
38.     }   
39.   
40.     /**  
41.      * @inheritdoc  
42.      */   
43.     public function attributeLabels()   
44.     {   
45.         return [   
46.             'id' => 'ID',   
47.             'name' => 'Name',   
48.             'designation' => 'Designation',   
49.             'contact' => 'Contact',   
50.             'email' => 'Email',   
51.        ];   
52.     }   
53. }   

In models, file EmployeesSearch.php will have the following code.

1. <?php   
2.   
3. namespace frontend\models;   
4.   
5. use Yii;   
6. use yii\base\Model;   
7. use yii\data\ActiveDataProvider;   
8. use frontend\models\Employees;   
9.   
10. /**  
11.  * EmployeesSearch represents the model behind the search form about `frontend\models\Employees`.  
12.  */   
13. class EmployeesSearch extends Employees   
14. {   
15.     /**  
16.      * @inheritdoc  
17.      */   
18.     public function rules()   
19.     {   
20.         return [   
21.             [['id', 'contact'], 'integer'],   
22.             [['name', 'designation', 'email'], 'safe'],   
23.         ];   
24.     }   
25.   
26.     /**  
27.      * @inheritdoc  
28.      */   
29.     public function scenarios()   
30.     {   
31.         // bypass scenarios() implementation in the parent class   
32.         return Model::scenarios();   
33.     }   
34.   
35.     /**  
36.      * Creates data provider instance with search query applied  
37.      *  
38.      * @param array $params  
39.      *  
40.      * @return ActiveDataProvider  
41.      */   
42.     public function search($params)   
43.     {   
44.        $query = Employees::find();   
45.   
46.         // add conditions that should always apply here   
47.   
48.         $dataProvider = new ActiveDataProvider([   
49.             'query' => $query,   
50.         ]);   
51.   
52.         $this->load($params);   
53.   
54.         if (!$this->validate()) {   
55.             // uncomment the following line if you do not want to return any   
56.     records when validation fails   
57.             // $query->where('0=1');   
58.             return $dataProvider;   
59.         }   
60.   
61.        // grid filtering conditions   
62.         $query->andFilterWhere([   
63.             'id' => $this->id,   
64.             'contact' => $this->contact,   
65.         ]);   
66.   
67.         $query->andFilterWhere(['like', 'name', $this->name])   
68.             ->andFilterWhere(['like', 'designation', $this->designation])   
69.             ->andFilterWhere(['like', 'email', $this->email]);   
70.   
71.         return $dataProvider;   
72.       }   
73.   }   

In views, file view.php will have the following code.

1. <?php   
2.   
3. use yii\helpers\Html;   
4. use yii\widgets\DetailView;   
5.   
6. /* @var $this yii\web\View */   
7. /* @var $model frontend\models\Employees */   
8.   
9. $this->title = $model->name;   
10. $this->params['breadcrumbs'][] = ['label' => 'Employees', 'url' => ['index']];   
11. $this->params['breadcrumbs'][] = $this->title;   
12. ?>   
13. <div class="employees-view">   
14.   
15.     <h1><?= Html::encode($this->title) ?></h1>   
16.   
17.     <p>   
18.        <?= Html::a('Update', ['update', 'id' => $model->id], ['class' => 'btn btn-primary']) ?>   
19.         <?= Html::a('Delete', ['delete', 'id' => $model->id], [   
20.             'class' => 'btn btn-danger',   
21.             'data' => [   
22.                 'confirm' => 'Are you sure you want to delete this item?',   
23.                 'method' => 'post',   
24.             ],   
25.         ]) ?>   
26.     </p>   
27.   
28.     <?= DetailView::widget([   
29.         'model' => $model,   
30.         'attributes' => [   
31.             'id',   
32.             'name',   
33.             'designation',   
34.             'contact',   
35.             'email:email',   
36.         ],   
37.     ]) ?>   
38.   
39. </div>   

In views, file form.php will have the following code.

1. <?php   
2.   
3. use yii\helpers\Html;   
4. use yii\widgets\ActiveForm;   
5.   
6. /* @var $this yii\web\View */   
7. /* @var $model frontend\models\Employees */   
8. /* @var $form yii\widgets\ActiveForm */   
9. ?>   
10.   
11. <div class="employees-form">   
12.   
13.     <?php $form = ActiveForm::begin(); ?>   
14.   
15.     <?= $form->field($model, 'name')->textInput(['maxlength' => true]) ?>   
16.   
17.     <?= $form->field($model, 'designation')->textInput(['maxlength' => true]) ?>   
18.   
19.     <?= $form->field($model, 'contact')->textInput() ?>   
20.   
21.     <?= $form->field($model, 'email')->textInput(['maxlength' => true]) ?>   
22.   
23.     <div class="form-group">   
24.         <?= Html::submitButton($model->isNewRecord ? 'Create' : 'Update', ['class' => $model->isNewRecord ? 'btn btn-success' : 'btn btn-primary']) ?>   
25.    </div>   
26.   
27.     <?php ActiveForm::end(); ?>   
28.   
29. </div>   

In views, file search.php will have the following code.

1. <?php   
2.   
3. use yii\helpers\Html;   
4. use yii\widgets\ActiveForm;   
5.   
6. /* @var $this yii\web\View */   
7. /* @var $model frontend\models\EmployeesSearch */   
8. /* @var $form yii\widgets\ActiveForm */   
9. ?>   
10.   
11. <div class="employees-search">   
12.   
13.     <?php $form = ActiveForm::begin([   
14.         'action' => ['index'],   
15.        'method' => 'get',   
16.     ]); ?>   
17.   
18.     <?= $form->field($model, 'id') ?>   
19.   
20.     <?= $form->field($model, 'name') ?>   
21.   
22.     <?= $form->field($model, 'designation') ?>   
23.   
24.     <?= $form->field($model, 'contact') ?>   
25.   
26.     <?= $form->field($model, 'email') ?>   
27.   
28.     <div class="form-group">   
29.         <?= Html::submitButton('Search', ['class' => 'btn btn-primary']) ?>   
30.        <?= Html::resetButton('Reset', ['class' => 'btn btn-default']) ?>   
31.     </div>   
32.   
33.     <?php ActiveForm::end(); ?>   
34.   
35. </div>   

In views, file create.php will have the following code.

1. <?php   
2.   
3. use yii\helpers\Html;   
4.   
5.   
6. /* @var $this yii\web\View */   
7. /* @var $model frontend\models\Employees */   
8.   
9. $this->title = 'Create Employees';   
10. $this->params['breadcrumbs'][] = ['label' => 'Employees', 'url' => ['index']];   
11. $this->params['breadcrumbs'][] = $this->title;   
12. ?>   
13. <div class="employees-create">   
14.   
15.     <h1><?= Html::encode($this->title) ?></h1>   
16.   
17.     <?= $this->render('_form', [   
18.         'model' => $model,   
19.     ]) ?>   
20.   
21. </div>   

In views, file index.php will have the following code.

1. <?php   
2.   
3. use yii\helpers\Html;   
4. use yii\grid\GridView;   
5.   
6. /* @var $this yii\web\View */   
7. /* @var $searchModel frontend\models\EmployeesSearch */   
8. /* @var $dataProvider yii\data\ActiveDataProvider */   
9.   
10. $this->title = 'Employees';   
11. $this->params['breadcrumbs'][] = $this->title;   
12. ?>   
13. <div class="employees-index">   
14.   
15.     <h1><?= Html::encode($this->title) ?></h1>   
16.     <?php // echo $this->render('_search', ['model' => $searchModel]); ?>   
17.   
18.     <p>   
19.         <?= Html::a('Create Employees', ['create'], ['class' => 'btn btn-success']) ?>   
20.     </p>   
21.     <?= GridView::widget([   
22.         'dataProvider' => $dataProvider,   
23.         'filterModel' => $searchModel,   
24.         'columns' => [   
25.             ['class' => 'yii\grid\SerialColumn'],   
26.   
27.             'id',   
28.             'name',   
29.             'designation',   
30.            'contact',   
31.             'email:email',   
32.   
33.             ['class' => 'yii\grid\ActionColumn'],   
34.         ],   
35.     ]); ?>   
36. </div>   

In views, file update.php will have the following code.

1. <?php   
2.   
3. use yii\helpers\Html;   
4.   
5. /* @var $this yii\web\View */   
6. /* @var $model frontend\models\Employees */   
7.   
8. $this->title = 'Update Employees: ' . $model->name;   
9. $this->params['breadcrumbs'][] = ['label' => 'Employees', 'url' => ['index']];   
10. $this->params['breadcrumbs'][] = ['label' => $model->name, 'url' => ['view', 'id' => $model->id]];   
11. $this->params['breadcrumbs'][] = 'Update';   
12. ?>   
13. <div class="employees-update">   
14.   
15.     <h1><?= Html::encode($this->title) ?></h1>   
16.   
17.     <?= $this->render('_form', [   
18.         'model' => $model,   
19.     ]) ?>   
20.   
21. </div>