Noticed

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Notifier Objects

Notifiers are essentially the controllers of the Noticed ecosystem and represent an Event. As such, we recommend naming them with the event they model in mind — be it a NewSaleNotifier, ChargeFailureNotifier, etc.

Notifiers must inherit from Noticed::Event. This provides all of their functionality.

A Notifier exists to declare the various delivery methods that should be used for that event and any notification helper methods necessary in those delivery mechanisms. In this example we’ll deliver by :action_cable to provide real-time UI updates to users’ browsers, :email if they’ve opted into email notifications, and a bulk notification to :discord to tell everyone on the Discord server there’s been a new comment.

# ~/app/notifiers/new_comment_notifier.rb

class NewCommentNotifier < Noticed::Event
  deliver_by :action_cable do |config|
    config.channel = "NotificationsChannel"
    config.stream = :some_stream
  end

  deliver_by :email do |config|
    config.mailer = "CommentMailer"
    config.if = ->(recipient) { !!recipient.preferences[:email] }
  end

  bulk_deliver_by :discord do |config|
    config.url = "https://discord.com/xyz/xyz/123"
    config.json = -> {
      {
        message: message,
        channel: :general
      }
    }
  end

  notification_methods do
    # I18n helpers
    def message
      t(".message")
    end

    # URL helpers are accessible in notifications
    # Don't forget to set your default_url_options so Rails knows how to generate urls
    def url
      user_post_path(recipient, params[:post])
    end
  end
end

For deeper specifics on setting up the :action_cable, :email, and :discord (bulk) delivery methods, refer to their docs: action_cable, email, and discord (bulk).

Delivery Method Configuration

Each delivery method can be configured with a block that yields a config object.

Procs/Lambdas will be evaluated when needed and symbols can be used to call a method.

When a lambda is passed, it will not pass any arguments and evaluates the Proc in the context of the Noticed::Notification

If you are using a symbol to call a method, we pass the notification object as an argument to the method. This allows you to access the notification object within the method. Your method must accept a single argument. If you don’t need to use the object you can just use (*).

Show Example

```ruby class CommentNotifier < Noticed::Event deliver_by :ios do |config| config.format = :ios_format config.apns_key = :ios_cert config.key_id = :ios_key_id config.team_id = :ios_team_id config.bundle_identifier = Rails.application.credentials.dig(:ios, :bundle_identifier) config.device_tokens = :ios_device_tokens config.if = -> { recipient.send_ios_notification? } end def ios_format(apn) apn.alert = { title:, body: } apn.mutable_content = true apn.content_available = true apn.sound = "notification.m4r" apn.custom_payload = { url:, type: self.class.name, id: record.id, image_url: "" || image_url, params: params.to_json } end def ios_cert(*) Rails.application.credentials.dig(:ios, Rails.env.to_sym, :apns_token_cert) end def ios_key_id(*) Rails.application.credentials.dig(:ios, Rails.env.to_sym, :key_id) end def ios_team_id(*) Rails.application.credentials.dig(:ios, Rails.env.to_sym, :team_id) end def ios_bundle_id(*) Rails.application.credentials.dig(:ios, Rails.env.to_sym, :bundle_identifier) end def ios_device_tokens(notification) notification.recipient.ios_device_tokens end def url comment_thread_path(record.thread) end end class Recipient < ApplicationRecord # or whatever your recipient model is has_many :ios_device_tokens def send_ios_notification? # some logic end end ```

More examples are in the docs for each delivery method.

Required Params

While explicit / required parameters are completely optional, Notifiers are able to opt in to required parameters via the required_params method:

class CarSaleNotifier < Noticed::Event
  deliver_by :email { |c| c.mailer = "BranchMailer" }

  # `record` is the Car record, `Branch` is the dealership
  required_params :branch

  # To validate the `:record` param, add a validation since it is an association on the Noticed::Event
  validates :record, presence: true
end

Which will validate upon any invocation that the specified parameters are present:

CarSaleNotifier.with(record: Car.last).deliver(Branch.last)
#=> Noticed::ValidationError("Param `branch` is required for CarSaleNotifier")

CarSaleNotifier.with(record: Car.last, branch: Branch.last).deliver(Branch.hq)
#=> OK

Helper Methods

Notifiers can implement various helper methods, within a notification_methods block, that make it easier to render the resulting notification directly. These helpers can be helpful depending on where and how you choose to render notifications. A common use is rendering a user’s notifications in your web UI as standard ERB. These notification helper methods make that rendering much simpler:

<div>
  <% @user.notifications.each do |notification| %>
    <%= link_to notification.message, notification.url %>
  <% end %>
</div>

On the other hand, if you’re using email delivery, ActionMailer has its own full stack for setting up objects and rendering. Your notification helper methods will always be available from the notification object, but using ActionMailer’s own paradigms may fit better for that particular delivery method. YMMV.

URL Helpers

Rails url helpers are included in Notifiers by default so you have full access to them in your notification helper methods, just like you would in your controllers and views.

But don’t forget, you’ll need to configure default_url_options in order for Rails to know what host and port to use when generating URLs.

Rails.application.routes.default_url_options[:host] = 'localhost:3000'

Translations

We’ve also included Rails’ translate and t helpers for you to use in your notification helper methods. This also provides an easy way of scoping translations. If the key starts with a period, it will automatically scope the key under notifiers, the underscored name of the notifier class, and notification. For example:

From the above Notifier…

class NewCommentNotifier < Noticed::Event
  # ...

  notification_methods do
    def message
      t(".message")
    end
  end

  # ...
end

Calling the message helper in an ERB view:

<%= @user.notifications.last.message %>

Will look for the following translation path:

# ~/config/locales/en.yml

en:
  notifiers:
    new_comment_notifier:
      notification:
        message: "Someone posted a new comment!"

Or, if you have your Notifier within another module, such as Admin::NewCommentNotifier, the resulting lookup path will be en.notifiers.admin.new_comment_notifier.notification.message (modules become nesting steps).

Tip: Extracting Delivery Method Configurations

If you want to reuse delivery method configurations across multiple Notifiers, you can extract them into a module and include them in your Notifiers.

# /app/notifiers/notifiers/comment_notifier.rb
class CommentNotifier < Noticed::Event
  include IosNotifier
  include AndriodNotifer
  include EmailNotifier

  validates :record, presence: true
end

### 📨 Sending Notifications

Following the `NewCommentNotifier` example above, here’s how we might invoke the Notifier to send notifications to every author in the thread about a new comment being added:

```ruby
NewCommentNotifier.with(record: @comment, foo: "bar").deliver(@comment.thread.all_authors)

This instantiates a new NewCommentNotifier with params (similar to ActiveJob, any serializable params are permitted), then delivers notifications to all authors in the thread.

✨ The record: param is a special param that gets assigned to the record polymorphic association in the database. You should try to set the record: param where possible. This may be best understood as ‘the record/object this notification is _about_’, and allows for future queries from the record-side: “give me all notifications that were generated from this comment”.

This invocation will create a single Noticed::Event record and a Noticed::Notification record for each recipient. A background job will then process the Event and fire off a separate background job for each bulk delivery method and each recipient + individual-delivery-method combination. In this case, that’d be the following jobs kicked off from this event:

A bulk delivery job for :discord bulk delivery
An individual delivery job for :action_cable method to the first thread author
An individual delivery job for :email method to the first thread author
An individual delivery job for :action_cable method to the second thread author
An individual delivery job for :email method to the second thread author
Etc…

Custom Noticed Model Methods

In order to extend the Noticed models you’ll need to use a concern and a to_prepare block:

# config/application.rb
module MyApp
  class Application < Rails::Application

    # ...

    config.to_prepare do
      Noticed::Event.include Noticed::EventExtensions
      Noticed::Notification.include Noticed::NotificationExtensions
    end
  end
end

✅ Best Practices

Renaming Notifiers

If you rename a Notifier class your existing data and Noticed setup may break. This is because Noticed serializes the class name and sets it to the type column on the Noticed::Event record and the type column on the Noticed::Notification record.

When renaming a Notifier class you will need to backfill existing Events and Notifications to reference the new name.

Noticed::Event.where(type: "OldNotifierClassName").update_all(type: NewNotifierClassName.name)
# and
Noticed::Notification.where(type: "OldNotifierClassName::Notification").update_all(type: "#{NewNotifierClassName.name}::Notification")

🚛 Delivery Methods

The delivery methods are designed to be modular so you can customize the way each type gets delivered.

For example, emails will require a subject, body, and email address while an SMS requires a phone number and simple message. You can define the formats for each of these in your Notifier and the delivery method will handle the processing of it.

Individual delivery methods:

ActionCable
Apple Push Notification Service
Email
Firebase Cloud Messaging (iOS, Android, and web clients)
Microsoft Teams
Slack
Twilio Messaging - SMS, Whatsapp
Vonage SMS
Test

Bulk delivery methods:

No Delivery Methods

It’s worth pointing out that you can have a fully-functional and useful Notifier that has no delivery methods. This means that invoking the Notifier and ‘sending’ the notification will only create new database records (no external surfaces like email, sms, etc.). This is still useful as it’s the database records that allow your app to render a user’s (or other object’s) notifications in your web UI.

So even with no delivery methods set, this example is still perfectly available and helpful:

<div>
  <% @user.notifications.each do |notification| %>
    <%= link_to notification.message, notification.url %>
  <% end %>
</div>

Sending a notification is entirely an internal-to-your-app function. Delivery methods just get the word out! But many apps may be fully satisfied without that extra layer.

Fallback Notifications

A common pattern is to deliver a notification via a real (or real-ish)-time service, then, after some time has passed, email the user if they have not yet read the notification. You can implement this functionality by combining multiple delivery methods, the wait option, and the conditional if / unless option.

class NewCommentNotifier < Noticed::Event
  deliver_by :action_cable
  deliver_by :email do |config|
    config.mailer = "CommentMailer"
    config.wait = 15.minutes
    config.unless = -> { read? }
  end
end

Here a notification will be created immediately in the database (for display directly in your app’s web interface) and sent via ActionCable. If the notification has not been marked read after 15 minutes, the email notification will be sent. If the notification has already been read in the app, the email will be skipped.

A note here: notifications expose a #mark_as_read method, but your app must choose when and where to call that method.

You can mix and match the options and delivery methods to suit your application specific needs.

app/notifiers/delivery_methods/turbo_stream.rb

class DeliveryMethods::TurboStream < ApplicationDeliveryMethod def deliver

return unless recipient.is_a?(User)

notification.broadcast_update_to_bell
notification.broadcast_replace_to_index_count
notification.broadcast_prepend_to_index_list

end end


```ruby
#### Callbacks

Callbacks for delivery methods wrap the _actual_ delivery of the notification. You can use `before_deliver`, `around_deliver` and `after_deliver` in your custom delivery methods.

```ruby
class DeliveryMethods::Discord < Noticed::DeliveryMethod
  after_deliver do
    # Do whatever you want
  end
end

📦 Database Model

The Noticed database models include several helpful features to make working with notifications easier.

Notification

Class methods/scopes

(Assuming your user has_many :notifications, as: :recipient, class_name: "Noticed::Notification")

Sorting notifications by newest first:

@user.notifications.newest_first

Query for read or unread notifications:

user.notifications.read
user.notifications.unread

Marking all notifications as read or unread:

user.notifications.mark_as_read
user.notifications.mark_as_unread

Instance methods

Mark notification as read / unread:

@notification.mark_as_read
@notification.mark_as_read!
@notification.mark_as_unread
@notification.mark_as_unread!

Check if read / unread:

@notification.read?
@notification.unread?

Associating Notifications

Adding notification associations to your models makes querying, rendering, and managing notifications easy (and is a pretty critical feature of most applications).

There are two ways to associate your models to notifications:

Where your object has_many notifications as the recipient (who you sent the notification to)
Where your object has_many notifications as the record (what the notifications were about)

In the former, we’ll use a has_many to :notifications. In the latter, we’ll actually has_many to :events, since records generate notifiable events (and events generate notifications).

We can illustrate that in the following:

class User < ApplicationRecord
  has_many :notifications, as: :recipient, dependent: :destroy, class_name: "Noticed::Notification"
end

# All of the notifications the user has been sent
# @user.notifications.each { |n| render(n) }

class Post < ApplicationRecord
  has_many :noticed_events, as: :record, dependent: :destroy, class_name: "Noticed::Event"
  has_many :notifications, through: :noticed_events, class_name: "Noticed::Notification"
end

# All of the notification events this post generated
# @post.notifications

ActiveJob Parent Class

Noticed uses its own Noticed::ApplicationJob as the base job for all notifications. In the event that you would like to customize the parent job class, there is a parent_class attribute that can be overridden with your own class. This should be done in a noticed.rb initializer.

Noticed.parent_class = "ApplicationJob"

Handling Deleted Records

Generally we recommend using a dependent: ___ relationship on your models to avoid cases where Noticed Events or Notifications are left lingering when your models are destroyed. In the case that they are or data becomes mis-matched, you’ll likely run into deserialization issues. That may be globally alleviated with the following snippet, but use with caution.

class ApplicationJob < ActiveJob::Base
  discard_on ActiveJob::DeserializationError
end

Customizing the Database Models

You can modify the database models by editing the generated migrations.

One common adjustment is to change the IDs to UUIDs (if you’re using UUIDs in your app).

You can also add additional columns to the Noticed::Event and Noticed::Notification models.

# This migration comes from noticed (originally 20231215190233)
class CreateNoticedTables < ActiveRecord::Migration[7.1]
  def change
    create_table :noticed_events, id: :uuid do |t|
      t.string :type
      t.belongs_to :record, polymorphic: true, type: :uuid
      t.jsonb :params

      # Custom Fields
      t.string :organization_id, type: :uuid, as: "((params ->> 'organization_id')::uuid)", stored: true
      t.virtual :action_type, type: :string, as: "((params ->> 'action_type'))", stored: true
      t.virtual :url, type: :string, as: "((params ->> 'url'))", stored: true

      t.timestamps
    end

    create_table :noticed_notifications, id: :uuid do |t|
      t.string :type
      t.belongs_to :event, null: false, type: :uuid
      t.belongs_to :recipient, polymorphic: true, null: false, type: :uuid
      t.datetime :read_at
      t.datetime :seen_at

      t.timestamps
    end

    add_index :noticed_notifications, :read_at
  end
end

The custom fields in the above example are stored as virtual columns. These are populated from values passed in the params hash when creating the notifier.

Noticed

Noticed

🎬 Screencast

Notifier Objects

Delivery Method Configuration

Required Params

Helper Methods

URL Helpers

Translations

Tip: Extracting Delivery Method Configurations

Custom Noticed Model Methods

✅ Best Practices

Renaming Notifiers

🚛 Delivery Methods

No Delivery Methods

Fallback Notifications

app/notifiers/delivery_methods/turbo_stream.rb

📦 Database Model

Notification

Class methods/scopes

Instance methods

Associating Notifications

ActiveJob Parent Class

Handling Deleted Records

Customizing the Database Models

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