require "delegate"
module ActionMailer
# The <tt>ActionMailer::MessageDelivery</tt> class is used by
# <tt>ActionMailer::Base</tt> when creating a new mailer.
# <tt>MessageDelivery</tt> is a wrapper (+Delegator+ subclass) around a lazy
# created <tt>Mail::Message</tt>. You can get direct access to the
# <tt>Mail::Message</tt>, 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)
#
# By default, the email will be enqueued using <tt>ActionMailer::DeliveryJob</tt>. Each
# <tt>ActionMailer::Base</tt> class can specify the job to use by setting the class variable
# +delivery_job+.
#
# class AccountRegistrationMailer < ApplicationMailer
# self.delivery_job = RegistrationDeliveryJob
# end
#
# Options:
#
# * <tt>:wait</tt> - Enqueue the email to be delivered with a delay
# * <tt>:wait_until</tt> - Enqueue the email to be delivered at (after) a specific date / time
# * <tt>:queue</tt> - 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)
#
# By default, the email will be enqueued using <tt>ActionMailer::DeliveryJob</tt>. Each
# <tt>ActionMailer::Base</tt> class can specify the job to use by setting the class variable
# +delivery_job+.
#
# class AccountRegistrationMailer < ApplicationMailer
# self.delivery_job = RegistrationDeliveryJob
# end
#
# Options:
#
# * <tt>:wait</tt> - Enqueue the email to be delivered with a delay.
# * <tt>:wait_until</tt> - Enqueue the email to be delivered at (after) a specific date / time.
# * <tt>:queue</tt> - 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
job = @mailer_class.delivery_job
job.set(options).perform_later(*args)
end
end
end
end