Important
Noticed is a gem that allows your application to send notifications of varying types, over various mediums, to various recipients. Be it a Slack notification to your own team when some internal event occurs or a notification to your user, sent as a text message, email, and real-time UI element in the browser, Noticed supports all of the above (at the same time)!
Noticed implements two top-level types of delivery methods:
- Individual Deliveries: Where each recipient gets their own notification
Show Example
Let’s use a car dealership as an example here. When someone purchases a car, a notification will be sent to the buyer with some contract details (“Congrats on your new 2024 XYZ Model...”), another to the car sales-person with different details (“You closed X deal; your commission is Y”), and another to the bank handling the loan with financial details (“New loan issued; amount $20,000...”). The event (the car being sold) necessitates multiple notifications being sent out to different recipients, but each contains its own unique information and should be separate from the others. These are individual deliveries.
- Bulk Deliveries: One notification for all recipients. This is useful for sending a notification to your Slack team, for example.
Show Example
Let’s continue with the car-sale example here. Consider that your development team created the car-sales application that processed the deal above and sent out the notifications to the three parties. For the sake of team morale and feeling the ‘wins’, you may want to implement a notification that notifies your internal development team whenever a car sells through your platform. In this case, you’ll be notifying many people (your development team, maybe others at your company) but with the same content (“someone just bought a car through our platform!”). This is a bulk delivery. It’s generally a single notification that many people just need to be made aware of.Bulk deliveries are typically used to push notifications to other platforms where users are managed (Slack, Discord, etc.) instead of your own.
Delivery methods we officially support:
- ActionCable
- Apple Push Notification Service
- Firebase Cloud Messaging (iOS, Android, and web clients)
- Microsoft Teams
- Slack
- Twilio Messaging - SMS, Whatsapp
- Vonage SMS
- Test
Bulk delivery methods we support:
Run the following command to add Noticed to your Gemfile:
bundle add "noticed"
Generate then run the migrations:
rails noticed:install:migrations
rails db:migrate
Noticed operates with a few constructs: Notifiers, delivery methods, and Notification records.
To start, generate a Notifier:
rails generate noticed:notifier NewCommentNotifier
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).
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
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 Recipent < 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.
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
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.
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'
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).
You can use the if:
and unless:
options on your delivery methods to check the user's preferences and skip processing if they have disabled that type of notification.
For example:
class CommentNotifier < Noticed::Event
deliver_by :email do |config|
config.mailer = 'CommentMailer'
config.method = :new_comment
config.if = ->{ recipient.email_notifications? }
end
end
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
# /app/notifiers/concerns/ios_notifier.rb
module IosNotifier
extend ActiveSupport::Concern
included do
deliver_by :ios do |config|
config.device_tokens = ->(recipient) { recipient.notification_tokens.where(platform: :iOS).pluck(:token) }
config.format = ->(apn) {
apn.alert = "Hello world"
apn.custom_payload = {url: root_url(host: "example.org")}
}
config.bundle_identifier = Rails.application.credentials.dig(:ios, :bundle_id)
config.key_id = Rails.application.credentials.dig(:ios, :key_id)
config.team_id = Rails.application.credentials.dig(:ios, :team_id)
config.apns_key = Rails.application.credentials.dig(:ios, :apns_key)
config.if = ->(recipient) { recipient.ios_notifications? }
end
end
end
Each of these options are available for every delivery method (individual or bulk). The value passed may be a lambda, a symbol that represents a callable method, a symbol value, or a string value.
config.if
— Intended for a lambda or method; runs after thewait
if configured; cancels the delivery method if returns falseyconfig.unless
— Intended for a lambda or method; runs after thewait
if configured; cancels the delivery method if returns truthyconfig.wait
— (Should yield anActiveSupport::Duration
) Delays the job that runs this delivery method for the given duration of timeconfig.wait_until
— (Should yield a specific time object) Delays the job that runs this delivery method until the specific time specifiedconfig.queue
— Sets the ActiveJob queue name to be used for the job that runs this delivery method
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:
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...
In order to extend the Noticed models you'll need to use a concern an a to_prepare block:
# config/initializers/noticed.rb
module NotificationExtensions
extend ActiveSupport::Concern
included do
belongs_to :organisation
scope :filter_by_type, ->(type) { where(type:) }
scope :exclude_type, ->(type) { where.not(type:) }
end
# You can also add instance methods here
end
Rails.application.config.to_prepare do
# You can extend Noticed::Event or Noticed::Notification here
Noticed::Event.include EventExtensions
Noticed::Notification.include NotificationExtensions
end
The NotificationExtensions
class could be separated into it's own file and live somewhere like app/models/concerns/notification_extensions.rb
.
If you do this, the to_prepare
block will need to be in application.rb
instead of an initializer.
# 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
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")
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
- Firebase Cloud Messaging (iOS, Android, and web clients)
- Microsoft Teams
- Slack
- Twilio Messaging - SMS, Whatsapp
- Vonage SMS
- Test
Bulk 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.
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.
If you want to build your own delivery method to deliver notifications to a specific service or medium that Noticed doesn’t (or doesn’t yet) support, you’re welcome to do so! To generate a custom delivery method, simply run
rails generate noticed:delivery_method Discord
This will generate a new DeliveryMethods::Discord
class inside the app/notifiers/delivery_methods
folder, which can be used to deliver notifications to Discord.
class DeliveryMethods::Discord < ApplicationDeliveryMethod
# Specify the config options your delivery method requires in its config block
required_options # :foo, :bar
def deliver
# Logic for sending the notification
end
end
You can use the custom delivery method thus created by adding a deliver_by
line with a unique name and class
option in your notification class.
class MyNotifier < Noticed::Event
deliver_by :discord, class: "DeliveryMethods::Discord"
end
Turbo Stream Custom Delivery Method Example
A common custom delivery method in the Rails world might be to Delivery to the web via turbo stream.
Note: This example users custom methods that extend the Noticed::Notification
class.
See the Custom Noticed Model Methods section for more information.
# 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
# app/models/concerns/noticed/notification_extensions.rb
module Noticed::NotificationExtensions
extend ActiveSupport::Concern
def broadcast_update_to_bell
broadcast_update_to(
"notifications_#{recipient.id}",
target: "notification_bell",
partial: "navbar/notifications/bell",
locals: { user: recipient }
)
end
def broadcast_replace_to_index_count
broadcast_replace_to(
"notifications_index_#{recipient.id}",
target: "notification_index_count",
partial: "notifications/notifications_count",
locals: { count: recipient.reload.notifications_count, unread: recipient.reload.unread_notifications_count }
)
end
def broadcast_prepend_to_index_list
broadcast_prepend_to(
"notifications_index_list_#{recipient.id}",
target: "notifications",
partial: "notifications/notification",
locals: { notification: self }
)
end
end
Delivery methods have access to the following methods and attributes:
event
— TheNoticed::Event
record that spawned the notification object currently being deliveredrecord
— The object originally passed into the Notifier as therecord:
param (see the ✨ note above)notification
— TheNoticed::Notification
instance being delivered. All notification helper methods are available on this objectrecipient
— The individual recipient object being delivered to for this notification (remember that each recipient gets their own instance of the Delivery Method#deliver
)config
— The hash of configuration options declared by the Notifier that generated this notification and deliveryparams
— The parameters given to the Notifier in the invocation (via.with()
)
The presence of delivery method config options are automatically validated when declaring them with the required_options
method. In the following example, Noticed will ensure that any Notifier using deliver_by :email
will specify the mailer
and method
config keys:
class DeliveryMethods::Email < Noticed::DeliveryMethod
required_options :mailer, :method
def deliver
# ...
method = config.method
end
end
If you’d like your config options to support dynamic resolution (set config.foo
to a lambda or symbol of a method name etc.), you can use evaluate_option
:
class NewSaleNotifier < Noticed::Event
deliver_by :whats_app do |config|
config.day = -> { is_tuesday? "Tuesday" : "Not Tuesday" }
end
end
class DeliveryMethods::WhatsApp < Noticed::DeliveryMethod
required_options :day
def deliver
# ...
config.day #=> #<Proc:0x000f7c8 (lambda)>
evaluate_option(config.day) #=> "Tuesday"
end
end
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.
class DeliveryMethods::Discord < Noticed::DeliveryMethod
after_deliver do
# Do whatever you want
end
end
The Noticed database models include several helpful features to make working with notifications easier.
(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
Convert back into a Noticed notifier object:
@notification.to_notifier
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?
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 therecord
(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 record
s 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
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"
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
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 :organisation_id, type: :uuid, as: "((params ->> 'organisation_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.
This project uses Standard for formatting Ruby code. Please make sure to run standardrb
before submitting pull requests.
Running tests against multiple databases locally:
DATABASE_URL=sqlite3:noticed_test rails test
DATABASE_URL=trilogy://root:@127.0.0.1/noticed_test rails test
DATABASE_URL=postgres://127.0.0.1/noticed_test rails test
The gem is available as open source under the terms of the MIT License.