require "delegate" module ActionMailer # The ActionMailer::MessageDelivery class is used by # ActionMailer::Base when creating a new mailer. # MessageDelivery is a wrapper (+Delegator+ subclass) around a lazy # created Mail::Message. You can get direct access to the # Mail::Message, deliver the email or schedule the email to be sent # through Active Job. # # Notifier.welcome(User.first) # an ActionMailer::MessageDelivery object # Notifier.welcome(User.first).deliver_now # sends the email # Notifier.welcome(User.first).deliver_later # enqueue email delivery as a job through Active Job # Notifier.welcome(User.first).message # a Mail::Message object class MessageDelivery < Delegator def initialize(mailer_class, action, *args) #:nodoc: @mailer_class, @action, @args = mailer_class, action, args # The mail is only processed if we try to call any methods on it. # Typical usage will leave it unloaded and call deliver_later. @processed_mailer = nil @mail_message = nil end # Method calls are delegated to the Mail::Message that's ready to deliver. def __getobj__ #:nodoc: @mail_message ||= processed_mailer.message end # Unused except for delegator internals (dup, marshaling). def __setobj__(mail_message) #:nodoc: @mail_message = mail_message end # Returns the resulting Mail::Message def message __getobj__ end # Was the delegate loaded, causing the mailer action to be processed? def processed? @processed_mailer || @mail_message end # Enqueues the email to be delivered through Active Job. When the # job runs it will send the email using +deliver_now!+. That means # that the message will be sent bypassing checking +perform_deliveries+ # and +raise_delivery_errors+, so use with caution. # # Notifier.welcome(User.first).deliver_later! # Notifier.welcome(User.first).deliver_later!(wait: 1.hour) # Notifier.welcome(User.first).deliver_later!(wait_until: 10.hours.from_now) # # Options: # # * :wait - Enqueue the email to be delivered with a delay # * :wait_until - Enqueue the email to be delivered at (after) a specific date / time # * :queue - Enqueue the email on the specified queue def deliver_later!(options = {}) enqueue_delivery :deliver_now!, options end # Enqueues the email to be delivered through Active Job. When the # job runs it will send the email using +deliver_now+. # # Notifier.welcome(User.first).deliver_later # Notifier.welcome(User.first).deliver_later(wait: 1.hour) # Notifier.welcome(User.first).deliver_later(wait_until: 10.hours.from_now) # # Options: # # * :wait - Enqueue the email to be delivered with a delay. # * :wait_until - Enqueue the email to be delivered at (after) a specific date / time. # * :queue - Enqueue the email on the specified queue. def deliver_later(options = {}) enqueue_delivery :deliver_now, options end # Delivers an email without checking +perform_deliveries+ and +raise_delivery_errors+, # so use with caution. # # Notifier.welcome(User.first).deliver_now! # def deliver_now! processed_mailer.handle_exceptions do message.deliver! end end # Delivers an email: # # Notifier.welcome(User.first).deliver_now # def deliver_now processed_mailer.handle_exceptions do message.deliver end end private # Returns the processed Mailer instance. We keep this instance # on hand so we can delegate exception handling to it. def processed_mailer @processed_mailer ||= @mailer_class.new.tap do |mailer| mailer.process @action, *@args end end def enqueue_delivery(delivery_method, options = {}) if processed? ::Kernel.raise "You've accessed the message before asking to " \ "deliver it later, so you may have made local changes that would " \ "be silently lost if we enqueued a job to deliver it. Why? Only " \ "the mailer method *arguments* are passed with the delivery job! " \ "Do not access the message in any way if you mean to deliver it " \ "later. Workarounds: 1. don't touch the message before calling " \ "#deliver_later, 2. only touch the message *within your mailer " \ "method*, or 3. use a custom Active Job instead of #deliver_later." else args = @mailer_class.name, @action.to_s, delivery_method.to_s, *@args ::ActionMailer::DeliveryJob.set(options).perform_later(*args) end end end end