Added Alert widget (#134)

views/layouts/main.php

@@ -3,6 +3,7 @@
 /* @var $this \yii\web\View */
 /* @var $content string */
 
+use app\widgets\Alert;
 use yii\helpers\Html;
 use yii\bootstrap\Nav;
 use yii\bootstrap\NavBar;
@@ -61,6 +62,7 @@ AppAsset::register($this);
         <?= Breadcrumbs::widget([
             'links' => isset($this->params['breadcrumbs']) ? $this->params['breadcrumbs'] : [],
         ]) ?>
+        <?= Alert::widget() ?>
         <?= $content ?>
     </div>
 </div>

widgets/Alert.php

@@ -0,0 +1,75 @@
+<?php
+namespace app\widgets;
+
+use Yii;
+
+/**
+ * Alert widget renders a message from session flash. All flash messages are displayed
+ * in the sequence they were assigned using setFlash. You can set message as following:
+ *
+ * ```php
+ * Yii::$app->session->setFlash('error', 'This is the message');
+ * Yii::$app->session->setFlash('success', 'This is the message');
+ * Yii::$app->session->setFlash('info', 'This is the message');
+ * ```
+ *
+ * Multiple messages could be set as follows:
+ *
+ * ```php
+ * Yii::$app->session->setFlash('error', ['Error 1', 'Error 2']);
+ * ```
+ *
+ * @author Kartik Visweswaran <kartikv2@gmail.com>
+ * @author Alexander Makarov <sam@rmcreative.ru>
+ */
+class Alert extends \yii\bootstrap\Widget
+{
+    /**
+     * @var array the alert types configuration for the flash messages.
+     * This array is setup as $key => $value, where:
+     * - $key is the name of the session flash variable
+     * - $value is the bootstrap alert type (i.e. danger, success, info, warning)
+     */
+    public $alertTypes = [
+        'error'   => 'alert-danger',
+        'danger'  => 'alert-danger',
+        'success' => 'alert-success',
+        'info'    => 'alert-info',
+        'warning' => 'alert-warning'
+    ];
+    /**
+     * @var array the options for rendering the close button tag.
+     */
+    public $closeButton = [];
+
+
+    public function init()
+    {
+        parent::init();
+
+        $session = Yii::$app->session;
+        $flashes = $session->getAllFlashes();
+        $appendCss = isset($this->options['class']) ? ' ' . $this->options['class'] : '';
+
+        foreach ($flashes as $type => $data) {
+            if (isset($this->alertTypes[$type])) {
+                $data = (array) $data;
+                foreach ($data as $i => $message) {
+                    /* initialize css class for each alert box */
+                    $this->options['class'] = $this->alertTypes[$type] . $appendCss;
+
+                    /* assign unique id to each alert box */
+                    $this->options['id'] = $this->getId() . '-' . $type . '-' . $i;
+
+                    echo \yii\bootstrap\Alert::widget([
+                        'body' => $message,
+                        'closeButton' => $this->closeButton,
+                        'options' => $this->options,
+                    ]);
+                }
+
+                $session->removeFlash($type);
+            }
+        }
+    }
+}