Active Webhook

gem 'active_webhook'

# in db/migrate/20210618023338_create_active_webhook_topics.rb

# This is just an example, you can define any topic keys that you want to define
class CreateActiveWebhookTopics < ActiveRecord::Migration[4.2]
  def change
    # If you do omit a value for`version` when creating a Topic, ActiveWebhook will autoincrement one for you.
    ActiveWebhook::Topic.create(key: "user/created")
  end
end

ActiveWebhook::Subscription.create(
  callback_url: 'http://myappdomain.com/webhooks',
  topic: ActiveWebhook::Topic.find_by_key('user/created')
)
# or
ActiveWebhook::Subscription.create(
  callback_url: 'http://myappdomain.com/webhooks',
  topic: ActiveWebhook::Topic.where(key: 'user/deleted', version: '1.1').first
)

ActiveWebhook.trigger(key: 'user/created')
ActiveWebhook.trigger(key: 'user/deleted', version: '1.1')
ActiveWebhook.trigger(key: 'user/deleted', data: { id: 1 }, my_option: 'random_value')

# app/models/application_record.rb

# note: trigger_webhooks is defined in ActiveWebhook::Callbacks, which is mixed into ActiveRecord::Base
class ApplicationRecord < ActiveRecord::Base
  # enable after_commit callbacks for created and deleted topic
  trigger_webhooks except: :updated

  # conditionally trigger the updated topic
  after_commit on: :updated do
    trigger_webhook :updated if state_changed?
  end
end

# app/models/invoice.rb

class Invoice < ApplicationRecord
  # override the default behavior to trigger an additional topic
  def trigger_updated_webhook
    trigger_webhook(:sent) if previous_changes.key?("sent_at")

    super
  end

# app/models/application_record.rb

class User < ApplicationRecord
  def send_reminder
    # this:
    trigger_webhook(:reminded)
    # is more-or-less equivalent to an optimized version of this:
    # ActiveWebhook.trigger(key: 'user/reminded', data: self.as_json, type: "resource")
  end
end

# in db/migrate/20210618023338_create_active_webhook_topics.rb

# This is just an example, you can define any topics that you want to define
class CreateActiveWebhookTopics < ActiveRecord::Migration[4.2]
  def change
    # define default callback topics for all models + a special topic
    ActiveRecord::Base.connection.tables.each do |table|
      %W(created updated deleted special).each do |event|
        ActiveWebhook::Topic.create(key: "#{table.singularize}/#{event}", version: "1.0")
      end
    end

    # define a second version of the user/created topic so we can conditionally deliver a different payload to subscribers
    ActiveWebhook::Topic.create(key: "user/created", version: "1.1")

    # define a custom topic
    ActiveWebhook::Topic.create(key: "invoice/sent")
  end
end

# in config/active_webhook.rb

require "active_webhook"

ActiveWebhook.configure do |config|
  config.adapters.queueing = :sidekiq
end

# in Gemfile

gem "sidekiq"

# db/migrate/20210618023339_add_company_to_active_webhook_subscriptions.rb

class AddCompanyToActiveWebhookSubscriptions < ActiveRecord::Migration[5.2]
  def change
    add_reference :active_webhook_subscriptions, :company
  end
end

# app/models/application_record.rb

# note: trigger_webhooks is defined in ActiveWebhook::Callbacks, which is mixed into ActiveRecord::Base
class ApplicationRecord < ActiveRecord::Base
  def trigger_webhook(key, version: nil, **context)
    context[:company_id] ||= company_id if respond_to?(:company_id)
    context[:company_id] ||= company&.id if respond_to?(:company)
    super
  end
end

# app/lib/webhook/queueing_adapter.rb

require "active_webhook/queueing/sidekiq_adapter"

module Webhook
  class QueueingAdapter < ActiveWebhook::Queueing::SidekiqAdapter
    # qualify subscriptions by tenant
    def subscriptions_scope
      scope = super
      scope = scope.where(company_id: company_id) if company_id.present?
      scope
    end

    def company_id
      context[:company_id]
    end
  end
end

# app/models/active_webhook/subscription.rb

# reopen class and add relation
class ActiveWebhook::Subscription
  belongs_to :company
end

# db/migrate/20210618023339_add_user_to_active_webhook_subscriptions.rb

class AddUserToActiveWebhookSubscriptions < ActiveRecord::Migration[4.2]
  def change
    add_reference :active_webhook_subscriptions, :user
  end
end

# app/models/company.rb

# note: trigger_webhooks is defined in ActiveWebhook::Callbacks, which is mixed into ActiveRecord::Base
class User < ApplicationRecord
  has_many :webhook_subscriptions
end

# app/models/webhook_subscription.rb

class WebhookSubscription < ApplicationRecord
  include ActiveWebhook::Models::SubscriptionAdditions
  belongs_to :user
end

# in config/active_webhook.rb

require "active_webhook"

ActiveWebhook.configure do |config|
  # use our custom Subscription class rather than the default
  config.models.subscription = WebhookSubscription
end

# in app/controllers/webhook_subscriptions
module Webhooks
  class SubscriptionsController < ApplicationController
    def create
      @user = User.find params.permit(:user_id)
      @user.webhook_subscriptions.build_webhook_subscription params.require(:webhook_subscription).permit(
        :callback_url,
        :topic_id
      )
      @user.save!
    end
  end
end

# in config/active_webhook.rb
ActiveWebhook.configure do |c|
  c.adapters.formatting = MySpecialFormatter
end

# in lib/webhooks/my_special_formatter.rb
# note: This is just an example. Custom formatters do not need to inherit from ActiveWebhook::Formatting::SimpleFormatting.
class Webhooks::MySpecialFormatter < ActiveWebhook::Formatting::JsonAdapter
  def self.call(subscription, **context)
    payload = super
    payload["type"] = "special" if subscription.topic_key.ends_with? "/special"
    payload.delete("something other key")
    payload
  end
end

# in config/active_webhook.rb
ActiveWebhook.configure do |c|
  c.adapters.formatting = Class.new(ActiveWebhook::Formatting::JsonAdapter) do
    def self.call(subscription, **context)
      payload = super
      payload["type"] = "special" if subscription.topic_key.ends_with? "/special"
      payload.delete("something other key")
      payload
    end
  end
end