feature #421 Notify post author about new comments by sending email (voronkovich, javiereguiluz)

This PR was merged into the master branch.

Discussion
----------

Notify post author about new comments by sending email

See #420

Commits
-------

7dc958c Change prefix for translation messages
f918956 Use '_fragment' parameter
1e83a1d Final round of help notes improvements
bbc4077 Improved more help notes
a596761 Improved some help notes
ec601b6 Minor reword in the help note
f37e552 Minor tweaks in the translation strings
4125af9 Add note about event listener's method
f3b258a Remove default value for sender property
b4a97be Use event listener and custom event trigger
7b6ba9a Notify post author about new comments

Author: javiereguiluz

app/AppKernel.php

@@ -22,8 +22,7 @@ public function registerBundles()
             new CodeExplorerBundle\CodeExplorerBundle(),
             new AppBundle\AppBundle(),
             new Doctrine\Bundle\FixturesBundle\DoctrineFixturesBundle(), // used for initial population of non-SQLite databases in production envs
-            // uncomment the following line if your application sends emails
-            // new Symfony\Bundle\SwiftmailerBundle\SwiftmailerBundle(),
+            new Symfony\Bundle\SwiftmailerBundle\SwiftmailerBundle(),
         ];
 
         // Some bundles are only used while developing the application or during

app/Resources/translations/messages.en.xlf

@@ -281,6 +281,15 @@
                 <target>Post deleted successfully!</target>
             </trans-unit>
 
+            <trans-unit id="notification.comment_created">
+                <source>notification.comment_created</source>
+                <target>Your post received a comment!</target>
+            </trans-unit>
+            <trans-unit id="notification.comment_created.description">
+                <source>notification.comment_created.description</source>
+                <target><![CDATA[Your post "%title%" has received a new comment. You can read the comment by following <a href="%link%">this link</a>]]></target>
+            </trans-unit>
+
             <trans-unit id="help.app_description">
                 <source>help.app_description</source>
                 <target><![CDATA[This is a <strong>demo application</strong> built in the Symfony Framework to illustrate the recommended way of developing Symfony applications.]]></target>

app/Resources/views/blog/post_show.html.twig

@@ -30,6 +30,7 @@
 
     {% for comment in post.comments %}
         <div class="row post-comment">
+            <a name="comment_{{ comment.id }}"></a>
             <h4 class="col-sm-3">
                 <strong>{{ comment.authorEmail }}</strong> {{ 'post.commented_on'|trans }}
                 {# it's not mandatory to set the timezone in localizeddate(). This is done to

app/config/config.yml

@@ -83,9 +83,9 @@ doctrine:
 # stores options that change the application behavior and parameters.yml
 # stores options that change from one server to another
 #
-# swiftmailer:
-#     transport: "%mailer_transport%"
-#     host:      "%mailer_host%"
-#     username:  "%mailer_user%"
-#     password:  "%mailer_password%"
-#     spool:     { type: memory }
+swiftmailer:
+    transport: "%mailer_transport%"
+    host:      "%mailer_host%"
+    username:  "%mailer_user%"
+    password:  "%mailer_password%"
+    spool:     { type: memory }

app/config/config_dev.yml

@@ -29,5 +29,5 @@ monolog:
         #    type:   chromephp
         #    level:  info
 
-#swiftmailer:
-#    delivery_address: [email protected]
+swiftmailer:
+    disable_delivery:  true

app/config/parameters.yml.dist

@@ -31,12 +31,9 @@ parameters:
     # $ php bin/console doctrine:schema:create
     # $ php bin/console doctrine:fixtures:load
 
-    # Uncomment these parameters if your application sends emails:
-    #
-    # mailer_transport:  smtp
-    # mailer_host:       127.0.0.1
-    # mailer_user:       ~
-    # mailer_password:   ~
-    #
     # If you don't use a real mail server, you can send emails via your Gmail account.
     # see http://symfony.com/doc/current/cookbook/email/gmail.html
+    mailer_transport:  smtp
+    mailer_host:       127.0.0.1
+    mailer_user:       ~
+    mailer_password:   ~

app/config/services.yml

@@ -31,9 +31,17 @@ services:
         tags:
             - { name: kernel.event_listener, event: kernel.request, method: onKernelRequest }
 
-    # Event subscribers are similar to event listeners but they don't need to add
-    # a separate tag for each listened event. Instead, the PHP class of the event
-    # subscriber includes a method that returns the list of listened events.
+    app.comment_notification:
+        class: AppBundle\EventListener\CommentNotificationListener
+        arguments: ['@mailer', '@router', '@translator', '%app.notifications.email_sender%']
+        # The "method" attribute of this tag is optional and defaults to "on + camelCasedEventName"
+        # If the event is "comment.created" the method executed by default is "onCommentCreated()".
+        tags:
+            - { name: kernel.event_listener, event: comment.created, method: onCommentCreated }
+
+    # Event subscribers are similar to event listeners but they don't need service tags.
+    # Instead, the PHP class of the event subscriber includes a method that returns
+    # the list of events listened by that class.
     # See http://symfony.com/doc/current/event_dispatcher.html#creating-an-event-subscriber
     app.console_subscriber:
         class: AppBundle\EventListener\ConsoleEventSubscriber

src/AppBundle/Controller/BlogController.php

@@ -13,13 +13,15 @@
 
 use AppBundle\Entity\Comment;
 use AppBundle\Entity\Post;
+use AppBundle\Events;
 use AppBundle\Form\CommentType;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Cache;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Method;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\ParamConverter;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
 use Sensio\Bundle\FrameworkExtraBundle\Configuration\Security;
 use Symfony\Bundle\FrameworkBundle\Controller\Controller;
+use Symfony\Component\EventDispatcher\GenericEvent;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
 
@@ -104,6 +106,20 @@ public function commentNewAction(Request $request, Post $post)
             $entityManager->persist($comment);
             $entityManager->flush();
 
+            // When triggering an event, you can optionally pass some information.
+            // For simple applications, use the GenericEvent object provided by Symfony
+            // to pass some PHP variables. For more complex applications, define your
+            // own event object classes.
+            // See http://symfony.com/doc/current/components/event_dispatcher/generic_event.html
+            $event = new GenericEvent($comment);
+
+            // When an event is dispatched, Symfony notifies it to all the listeners
+            // and subscribers registered to it. Listeners can modify the information
+            // passed in the event and they can even modify the execution flow, so
+            // there's no guarantee that the rest of this controller will be executed.
+            // See http://symfony.com/doc/current/components/event_dispatcher.html
+            $this->get('event_dispatcher')->dispatch(Events::COMMENT_CREATED, $event);
+
             return $this->redirectToRoute('blog_post', ['slug' => $post->getSlug()]);
         }
 

src/AppBundle/EventListener/CommentNotificationListener.php

@@ -0,0 +1,96 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace AppBundle\EventListener;
+
+use Symfony\Component\EventDispatcher\GenericEvent;
+use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
+use Symfony\Component\Translation\TranslatorInterface;
+
+/**
+ * Notifies post's author about new comments.
+ *
+ * @author Oleg Voronkovich <[email protected]>
+ */
+class CommentNotificationListener
+{
+    /**
+     * @var \Swift_Mailer
+     */
+    private $mailer;
+
+    /**
+     * @var TranslatorInterface
+     */
+    private $translator;
+
+    /**
+     * @var UrlGeneratorInterface
+     */
+    private $urlGenerator;
+
+    /**
+     * @var string
+     */
+    private $sender;
+
+    /**
+     * Constructor.
+     *
+     * @param \Swift_Mailer         $mailer
+     * @param UrlGeneratorInterface $urlGenerator
+     * @param TranslatorInterface   $translator
+     * @param string                $sender
+     */
+    public function __construct(\Swift_Mailer $mailer, UrlGeneratorInterface $urlGenerator, TranslatorInterface $translator, $sender)
+    {
+        $this->mailer = $mailer;
+        $this->urlGenerator = $urlGenerator;
+        $this->translator = $translator;
+        $this->sender = $sender;
+    }
+
+    /**
+     * @param GenericEvent $event
+     */
+    public function onCommentCreated(GenericEvent $event)
+    {
+        $comment = $event->getSubject();
+        $post = $comment->getPost();
+
+        $linkToPost = $this->urlGenerator->generate('blog_post', [
+            'slug' => $post->getSlug(),
+            '_fragment' => 'comment_'.$comment->getId(),
+        ], UrlGeneratorInterface::ABSOLUTE_URL);
+
+        $subject = $this->translator->trans('notification.comment_created');
+        $body = $this->translator->trans('notification.comment_created.description', [
+            '%title%' => $post->getTitle(),
+            '%link%' => $linkToPost,
+        ]);
+
+        // Symfony uses a library called SwiftMailer to send emails. That's why
+        // email messages are created instantiating a Swift_Message class.
+        // See http://symfony.com/doc/current/email.html#sending-emails
+        $message = \Swift_Message::newInstance()
+            ->setSubject($subject)
+            ->setTo($post->getAuthorEmail())
+            ->setFrom($this->sender)
+            ->setBody($body, 'text/html')
+        ;
+
+        // In app/config/config_dev.yml the 'disable_delivery' option is set to 'true'.
+        // That's why in the development environment you won't actually receive any email.
+        // However, you can inspect the contents of those unsent emails using the debug toolbar.
+        // See http://symfony.com/doc/current/email/dev_environment.html#viewing-from-the-web-debug-toolbar
+        $this->mailer->send($message);
+    }
+}

src/AppBundle/Events.php

@@ -0,0 +1,32 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace AppBundle;
+
+/**
+ * This class defines the names of all the events dispatched in
+ * the Symfony Demo application. It's not mandatory to create a
+ * class like this, but it's considered a good practice.
+ *
+ * @author Oleg Voronkovich <[email protected]>
+ */
+final class Events
+{
+    /**
+     * For the event naming conventions, see:
+     * http://symfony.com/doc/current/components/event_dispatcher.html#naming-conventions.
+     *
+     * @Event("Symfony\Component\EventDispatcher\GenericEvent")
+     *
+     * @var string
+     */
+    const COMMENT_CREATED = 'comment.created';
+}