devise-activejob.rb

# Dequeueing ActiveJob tasks in the context of your Rails application?  

# An alternative is to run a standalone ActiveJob process.  
# But making it dequeue and send devise emails isn't so simple.
# Devise is designed to be integrated into a Rails application, not a standalone ActiveJob process.

# Before we address configuring the standalone ActiveJob process, 
# there's some code that needs to go into your Rails app.
# Put this in each model in your Rails application:
#
#  def send_devise_notification(notification, *args)
#    devise_mailer.send(notification, self, *args).deliver_later
#  end
#
# Now, here's what it takes to get the standalone ActiveJob process working:

# 1. Configure your Queue Adapter.  This examples uses Delayed Job.
# See ActiveJob documentation for alternatives.  
# Make sure you pick a Queue Adapter that queues jobs using the database.
# Sidekiq, for instance, will not work for this.
require "delayed_job_active_record"

class Delayed::Worker
  self.sleep_delay = 20
  self.max_attempts = 11
end

# 2. Configure devise
# devise.rb requires a few files that we don't want to load, such as Rails.
# So we need to preempt it on the load path.
# See further instructions in rails.rb below.
$LOAD_PATH.unshift(File.expand_path(File.dirname(__FILE__)))

# There are a few methods that don't make sense outside of the Rails application,
# making it difficult to load devise.
# So we override them with empty implementation.
require "devise"

module Devise
  class << self
    def configure_warden!
    end
  end
  class Mapping
    def default_failure_app(arg)
    end
  end
end

Devise.setup do |config|
  require 'devise/orm/active_record'
  
  # This means that all the url helper methods will be delegated to a method called `routes`
  # See #7 below, where we define this method
  config.router_name = :routes
end

# Since we're not using a Railtie, devise's app folder won't be added to the LOAD_PATH.
# So we need to used some Bundler internals to get there.
require "action_mailer"
require File.join(
  Bundler.load.specs["devise"].first.full_gem_path, 
  "app", 
  "mailers",
  "devise",
  "mailer"
)

# 3. Configure ActionMailer
class ActionMailer::Base
  default 
    from: "me@mydomain.com", 
    protocol: "https", 
    host: "mydomain.com",
    smtp_settings: { address: "localhost", port: 25, enable_starttls_auto: false }

  self.raise_delivery_errors = true
  self.view_paths << File.join(Bundler.load.specs["devise"].first.full_gem_path, "app", "views")
end

# 4. Configure ActiveRecord to support ActiveJob serialization
require "global_id"
GlobalID.app = "MyApp"

class ActiveRecord::Base
  include GlobalID::Identification
end

# 5. Define your routes
ROUTES = begin
  require "action_dispatch/routing"
  require "devise/rails/routes"
  ActionDispatch::Routing::Mapper.send(:define_method, :raise_no_secret_key) {}
  route_set = ::ActionDispatch::Routing::RouteSet.new
  route_set.draw do
    default_url_options(
      host: "#{ActionMailer::Base.default_params[:protocol]}://#{ActionMailer::Base.default_params[:host]}"
    )
      
    devise_for :users, skip: :sessions
  end
  route_set.url_helpers(false)
end

# 6. Load all your models:
class User < ActiveRecord::Base
  devise :confirmable, :recoverable, :database_authenticatable, :lockable
end

# 7. Make all the routes into helper methods in your mailer views:
require "action_view"

class ActionView::Base
  include Devise::Controllers::UrlHelpers

  def routes
    @routes ||= ROUTES
  end
end

# 8. Load ActiveJob
require "active_job"

# 9. Configure the loggers:
ActiveJob::Base.logger = 
  ActionMailer::Base.logger = 
  ActiveRecord::Base.logger = 
  Delayed::Worker.logger = 
  ::Logger.new("/path/to/log.log")
  
# 10. Connect to the database
ActiveRecord::Base.establish_connection(ENV['DATABASE_URL'])

# 11. Make ActionView use the correct content type by default
# This is necessary so that we automatically set the Content Type based on the template's file extension.
# See https://github.com/rails/rails/issues/11157
autoload :Mime, 'action_dispatch/http/mime_type'
ActionView::Base.default_formats ||= Mime::SET.symbols
ActionView::Template::Types.delegate_to Mime

# 12. Run your delayed job worker
Delayed::Worker.new(queues: [:mailers]).start

rails.rb

# This file prevents devise from loading another file with the same name by pre-empting it on the load path
# Similar files must be created called responders.rb and devise/rails.rb