Notifications plugin for Craft CMS 3.x

Send notifications across a variety of delivery channels, including mail and Slack. Notifications may also be stored in a database so they may be displayed in your web interface.

1. Installation
2. Introduction
3. Sending notifications
4. Database notifications
   1. Retrieving notifications
   2. Marking notifications as read
5. Delete notifications
6. Mail notifications
7. Slack notifications
   1. Formatting slack notifications
   2. Customizing the Sender & Recipient
   3. Slack attachments
   4. Markdown attachment content
8. Notification events
9. Custom channels

Support Open Source. Buy beer.

This plugin is licensed under a MIT license, which means that it's completely free open source software, and you can use it for whatever and however you wish. If you're using it and want to support the development, buy me a beer over at Beerpay!

Requirements

This plugin requires Craft CMS 3.1.0 or later.

Installation

To install the plugin, follow these instructions.

1. Open your terminal and go to your Craft project:

    cd /path/to/project
   

2. Then tell Composer to load the plugin:

    composer require percipioglobal/craft-notifications
   

3. In the Control Panel, go to Settings → Plugins and click the “Install” button for Notifications.

4. Copy the config.php file to config/notifications.php in your application.

5. Make sure your notifications are autoloaded by adding the following to your composer.json and runnning composer dump -o

"autoload": {
    "psr-4": {
        "app\\notifications\\": "./notifications"
    }
},

Introduction

Typically, notifications should be short, informational messages that notify users of something that occurred in your application. For example, if you are writing a billing application, you might send an "Invoice Paid" notification to your users via the email and SMS channels.

Creating notifications

Each notification is represented by a single class (stored in the notifications directory of your application). You will have to create it manually or it will be created for you when you run the notifications/make command:

./craft notifications/make BlogPostAdded

This command will place a fresh notification class in your notifications directory. Each notification class contains a via method and a variable number of message building methods (such as toMail or toDatabase) that convert the notification to a message optimized for that particular channel.

Sending notifications

Notifications can be sent in two ways, either from the configuration file when an event is fired, or from your own plugins.

First, let's show how you configure sending a notification when for example a new blogpost is added:

<?php 
 
return [
    'notifications' => [
        [
            'class' => \craft\elements\Entry::class,
            'event' => \craft\elements\Entry::EVENT_AFTER_SAVE,
            'notification' => \app\notifications\BlogPostAdded::class,
        ],
    ],
];

Here we're listening from the EVENT_AFTER_SAVE event on the Entry class of Craft which will cause our notification to be triggered every time we save an entry.

In our BlogPostAdded class we can then use the via function to determine if and how we want to send the notification:

/**
 * Get the notification's delivery channels.
 *
 * @return array
 */
public function via()
{
    $entry = $this->event->sender;

    if ($entry->section->handle === 'blog' && $this->event->isNew) {
        return [
            'database' => Craft::$app->getUsers()->getUserByUsernameOrEmail('hello@percipio.london'),
        ];
    }

    return [];
}

We know the event is an ElementEvent, which contains the sender and an isNew property, using this information we can determine that we only want to send a notification when the entry is from the blog section and it's a new Entry.

Sending a notification from a plugin

From a plugin, you can use the notificationsService to send you own notifications.

use percipioglobal\notifications\Notifications; 
use app\notifications\BlogPostAdded; 
 
Notifications::getInstance()->notificationsService->send(new BlogPostAdded());

Database notifications

To save a notification in the database for later retrieval, make sure your via method returns the database key with a User object as value.

return [
    'database' => Craft::$app->getUsers()->getUserByUsernameOrEmail('hello@percipio.london'),
];

When using the database notification channel, your Notification class should define a toDatabase or toArray function.

This can be as simple as:

public function toDatabase()
{
    return ArrayHelper::toArray($this);
}

When retrieving the notifications from the database in your templates, the notification will contain the data that is passed here.

Retrieving notifications

The notifications plugin provides a template variable to retrieve notifications and mark them as read.

Let's see how we can loop over the notifications, this automatically uses the current logged in user to find notifications for:

  {% for notification in craft.notifications.unread %}
    {# The notification object contains all the data from the toDatabase or toArray function on your notification class #}
  {% endfor %}

You can also retrieve the notifications through the notificationsService

use percipioglobal\notifications\Notifications; 

// All unread notifications
Notifications::getInstance()->notificationsService->getAllUnread();

// All read notifications
Notifications::getInstance()->notificationsService->getAllRead();

// All notifications
Notifications::getInstance()->notificationsService->getAll();

Marking notifications as read

To mark notifications as read, we can use the Twig variable or the notificationsService as well. This function expects an array of notifications.

  {% for notification in craft.notifications.unread %}
    {{ craft.notifications.markAsRead(notification) }}
  {% endfor %}

use percipioglobal\notifications\Notifications; 

Notifications::getInstance()->notificationsService->markAsRead($notification);

Delete read notifications

To keep your database clean and lean, you can delete the read notifications older than a given time frame. The default time is set to -1 month. If you want a custom time frame, provide the date within the strtotime PHP restrictions.

./craft notifications/remove-notifications/index --time="-3 months"

Mail notifications

To configure a notification to be sent as an email, make sure your via method on the Notification class returns a key with mail:

return [
    'mail' => 'hello@percipio.london',
];

If a notification supports being sent as an email, you should define a toMail method on the notification class. This method will receive a $notifiable object that contains everything you defined in your via method.

The toMail function should return a craft\mail\Message instance. You may also return an array of craft\mail\Message instances if you wish to send multiple emails. Let's take a look at an example toMail method:

public function toMail($notifiable)
{
    $title = $this->event->sender->title;

    $message = new Message();
    $message->setTo($notifiable);
    $message->setSubject("A new blogpost was added");
    $message->setHtmlBody("
        <p>Hey there!</p>
        <p>A new blogpost was added with the title {$title}</p>
    ");

    return $message;
}

Slack notifications

You will need to configure an "Incoming Webhook" integration for your Slack team. This integration will provide you with a URL you may use when defining your via function.

return [
    'slack' => '<YOUR_WEBHOOK_URL>',
];

The implementation and documentation are mostly based on Laravel Notifications.

Formatting Slack notifications

If a notification supports being sent as a Slack message, you should define a toSlack method on the notification class. This method should return a percipioglobal\notifications\messages\SlackMessage instance. Slack messages may contain text content as well as an "attachment" that formats additional text or an array of fields. Let's take a look at a basic toSlack example:

/**
 * Get the Slack representation of the notification.
 *
 * @param  mixed  $notifiable
 * @return SlackMessage
 */
public function toSlack()
{
    return (new SlackMessage)
          ->content('A new blogpost was added!');
}

Customizing The Sender & Recipient

You may use the from and to methods to customize the sender and recipient. The from method accepts a username and emoji identifier, while the to method accepts a channel or username:

/**
 * Get the Slack representation of the notification.
 *
 * @param  mixed  $notifiable
 * @return SlackMessage
 */
public function toSlack($notifiable)
{
    return (new SlackMessage)
        ->from('Ghost', ':ghost:')
        ->to('#other')
        ->content('This will be sent to #other');
}

You may also use an image as your logo instead of an emoji:

/**
 * Get the Slack representation of the notification.
 *
 * @param  mixed  $notifiable
 * @return SlackMessage
 */
public function toSlack($notifiable)
{
    return (new SlackMessage)
        ->from('Laravel')
        ->image('https://yoursite.com/favicon.png')
        ->content('This will display your logo next to the message');
}

Slack attachments

You may also add "attachments" to Slack messages. Attachments provide richer formatting options than simple text messages. In this example, we will send an error notification about an exception that occurred in an application, including a link to view more details about the exception:

/**
 * Get the Slack representation of the notification.
 *
 * @param  mixed  $notifiable
 * @return SlackMessage
 */
public function toSlack($notifiable)
{
    $url = url('/exceptions/'.$this->exception->id);

    return (new SlackMessage)
        ->error()
        ->content('Whoops! Something went wrong.')
        ->attachment(function ($attachment) use ($url) {
            $attachment->title('Exception: File Not Found', $url)
                       ->content('File [background.jpg] was not found.');
        });
}

The example above will generate a Slack message that looks like the following:

Attachments also allow you to specify an array of data that should be presented to the user. The given data will be presented in a table-style format for easy reading:

/**
 * Get the Slack representation of the notification.
 *
 * @param  mixed  $notifiable
 * @return SlackMessage
 */
public function toSlack($notifiable)
{
    $url = url('/invoices/'.$this->invoice->id);

    return (new SlackMessage)
        ->success()
        ->content('One of your invoices has been paid!')
        ->attachment(function ($attachment) use ($url) {
            $attachment->title('Invoice 1322', $url)
                       ->fields([
                            'Title' => 'Server Expenses',
                            'Amount' => '$1,234',
                            'Via' => 'American Express',
                            'Was Overdue' => ':-1:',
                        ]);
        });
}

The example above will generate a Slack message that looks like the following:

Markdown Attachment Content

If some of your attachment fields contain Markdown, you may use the markdown method to instruct Slack to parse and display the given attachment fields as Markdown formatted text. The values accepted by this method are: pretext, text, and / or fields. For more information about Slack attachment formatting, check out the Slack API documentation:

/**
 * Get the Slack representation of the notification.
 *
 * @param  mixed  $notifiable
 * @return SlackMessage
 */
public function toSlack($notifiable)
{
    $url = url('/exceptions/'.$this->exception->id);

    return (new SlackMessage)
        ->error()
        ->content('Whoops! Something went wrong.')
        ->attachment(function ($attachment) use ($url) {
            $attachment->title('Exception: File Not Found', $url)
                       ->content('File [background.jpg] was *not found*.')
                       ->markdown(['text']);
        });
}

Notification Events

When a notification is sent, there are two events that get triggered, the NotificationsService::EVENT_BEFORE_SEND and NotificationsService::EVENT_AFTER_SEND which send a percipioglobal\notifications\events\SendEvent event.

The sendEvent contains the following properties:

/**
 * @var mixed The notifiable.
 */
public $notifiable;
 
/**
 * @var NotificationsRecord The notification about to be sent.
 */
public $notification;
 
/**
 * @var string The channel on which the notification is about to be sent.
 */
public $channel;
 
/**
 * @var bool Whether we send the notification
 */
public $sendNotification = true;
 
/**
 * @var mixed The response after sending the event
 */
public $response = null;

The sendNotification property can be changed when listening for EVENT_BEFORE_SEND to prevent the notification from being sent. The response property is only set on the EVENT_AFTER_SEND event.

Custom channels

Craft Notifications ships with three channels (database, mail & Slack), but you may want to write your own drivers to deliver notifications via other channels. We make this simple by exposing an event where you can register new channels.

Let's explore how we'd register a voice channel:

Event::on(
    NotificationsService::class,
    NotificationsService::EVENT_REGISTER_CHANNELS,
    function (RegisterChannelsEvent $event) {
        $event->channels[] = [
            'voice' => function () {
                return new VoiceChannel();
            },
        ];
    }
);

Your VoiceChannel class would then look like this:

<?php

namespace app\channels;

use percipioglobal\notifications\models\Notification;

class VoiceChannel
{
    /**
     * Send the given notification.
     *
     * @param  mixed  $notifiable
     * @param  \percipioglobal\notifications\models\Notification  $notification
     * @return void
     */
    public function send($notifiable, Notification $notification)
    {
        $message = $notification->toVoice($notifiable);

        // Send notification to the $notifiable...
    }
}

Once your notification channel class has been defined, you may simply add the key to your via method in your notifications. What the value should be depends on the implementation of your channel.

<?php

namespace App\Notifications;

use app\channels\VoiceChannel;
use app\channels\messages\VoiceMessage;
use percipioglobal\notifications\models\Notification;

class InvoicePaid extends Notification
{
    /**
     * Get the notification channels.
     *
     * @param  mixed  $notifiable
     * @return array|string
     */
    public function via($notifiable)
    {
        return [
            'voice' => '<YOUR_DESTINATION>',
        ];
    }

    /**
     * Get the voice representation of the notification.
     *
     * @param  mixed  $notifiable
     * @return VoiceMessage
     */
    public function toVoice($notifiable)
    {
        // ...
    }
}

The implementation of channels are very alike to how it's done with Laravel, if you need a specific channel there's a big chance you'll find one at Laravel Notification Channels that only needs a few implementation changes.

The functionality of adding a channel is very easily extracted to a plugin, if you implement a custom one, please consider sharing them with the community.

Brought to you by Percipio Global Ltd.