ChannelController: Disable the Add button and show message when no channel found

ChannelForm: Throw exception in case user access the form via url

Author: sukhwinder33445

application/controllers/ChannelsController.php

@@ -7,6 +7,7 @@
 use Icinga\Module\Notifications\Common\Database;
 use Icinga\Module\Notifications\Common\Links;
 use Icinga\Module\Notifications\Forms\ChannelForm;
+use Icinga\Module\Notifications\Model\AvailableChannelType;
 use Icinga\Module\Notifications\Model\Channel;
 use Icinga\Module\Notifications\View\ChannelRenderer;
 use Icinga\Module\Notifications\Web\Control\SearchBar\ObjectSuggestions;
@@ -15,6 +16,7 @@
 use Icinga\Web\Widget\Tab;
 use Icinga\Web\Widget\Tabs;
 use ipl\Sql\Connection;
+use ipl\Sql\Expression;
 use ipl\Stdlib\Filter;
 use ipl\Web\Compat\CompatController;
 use ipl\Web\Compat\SearchControls;
@@ -84,15 +86,25 @@ public function indexAction()
         $this->addControl($sortControl);
         $this->addControl($limitControl);
         $this->addControl($searchBar);
-        $this->addContent(
-            (new ButtonLink(t('Add Channel'), Links::channelAdd(), 'plus'))
-                ->setBaseTarget('_next')
-                ->addAttributes(['class' => 'add-new-component'])
-        );
 
+        $addButton = (new ButtonLink(
+            t('Add Channel'),
+            Links::channelAdd(),
+            'plus',
+            ['class' => 'add-new-component']
+        ))->setBaseTarget('_next');
+
+        $emptyStateMessage = null;
+        if (AvailableChannelType::on($this->db)->columns([new Expression('1')])->first() === null) {
+            $emptyStateMessage = t('No channel types available. Make sure Icinga Notifications is running.');
+            $addButton->disable($emptyStateMessage);
+        }
+
+        $this->addContent($addButton);
         $this->addContent(
             (new ObjectList($channels, new ChannelRenderer()))
                 ->setItemLayoutClass(MinimalItemLayout::class)
+                ->setEmptyStateMessage($emptyStateMessage)
         );
 
         if (! $searchBar->hasBeenSubmitted() && $searchBar->hasBeenSent()) {

application/forms/ChannelForm.php

@@ -5,6 +5,7 @@
 namespace Icinga\Module\Notifications\Forms;
 
 use DateTime;
+use Icinga\Exception\ConfigurationError;
 use Icinga\Exception\Http\HttpNotFoundException;
 use Icinga\Module\Notifications\Model\AvailableChannelType;
 use Icinga\Module\Notifications\Model\Channel;
@@ -55,8 +56,19 @@ public function __construct(Connection $db)
         $this->db = $db;
     }
 
+    /**
+     * @throws ConfigurationError
+     */
     protected function assemble()
     {
+        $query = AvailableChannelType::on($this->db)
+            ->columns(['type', 'name', 'config_attrs'])
+            ->execute();
+
+        if (! $query->hasResult()) {
+            throw new ConfigurationError('No channel types available. Make sure Icinga Notifications is running.');
+        }
+
         $this->addAttributes(['class' => 'channel-form']);
         $this->addElement($this->createCsrfCounterMeasure(Session::getSession()->getId()));
 
@@ -70,8 +82,6 @@ protected function assemble()
             ]
         );
 
-        $query = AvailableChannelType::on($this->db)->columns(['type', 'name', 'config_attrs']);
-
         /** @var string[] $typesConfig */
         $typesConfig = [];