Rails ActionMailer with multiple SMTP servers

Question

I have a need to use two different smtp servers in a Rails application. It appears that the way ActionMailer is constructed, it is not possible to have different smtp_settin

Answer 1

I'm afraid it's not doable natively.
But you can trick it a bit by modifying the @@smtp_settings variable in the model.

There's an article on Oreilly which explains it pretty well even though they code is not clean at all. http://broadcast.oreilly.com/2009/03/using-multiple-smtp-accounts-w.html

Answer 2

When I wanted a quick test in the console (Rails 5) I did the following:

settings = { username: "" } # etc
mailer = MyMailer.some_method
mailer.delivery_method.settings.merge!(settings)
mailer.deliver

Answer 3

Tried to use jkrall's option with Rails 3.2.1 but for some reason it wouldn't override default configuration, but doing:

MyMailer.my_email.delivery_method.settings.merge!(SMTP_SETTINGS).deliver

Similar to http://www.scottw.com/multiple-smtp-servers-with-action-mailer, made it work.

Answer 4

Rails-2.3.*

# app/models/user_mailer.rb
class UserMailer < ActionMailer::Base
  def self.smtp_settings
    USER_MAILER_SMTP_SETTINGS
  end

  def spam(user)
    recipients user.mail
    from 'spam@example.com'
    subject 'Enlarge whatever!'
    body :user => user
    content_type 'text/html'
  end
end

# config/environment.rb
ActionMailer::Base.smtp_settings = standard_smtp_settings
USER_MAILER_SMTP_SETTINGS = user_smtp_settings

# From console or whatever...
UserMailer.deliver_spam(user)

Answer 5

Solution for Rails 3.2:

class SomeMailer < ActionMailer::Base

  include AbstractController::Callbacks
  after_filter :set_delivery_options

  private
  def set_delivery_options
    settings = {
      :address => 'smtp.server',
      :port => 587,
      :domain => 'your_domain',
      :user_name => 'smtp_username',
      :password => 'smtp_password',
      :authentication => 'PLAIN' # or something
    }

    message.delivery_method.settings.merge!(settings)
  end
end

Solution inspired by How to send emails with multiple, dynamic smtp using Actionmailer/Ruby on Rails

Answer 6

class UserMailer < ActionMailer::Base
  def welcome_email(user, company)
    @user = user
    @url  = user_url(@user)
    delivery_options = { user_name: company.smtp_user,
                         password: company.smtp_password,
                         address: company.smtp_host }
    mail(to: @user.email,
         subject: "Please see the Terms and Conditions attached",
         delivery_method_options: delivery_options)
  end
end

Rails 4 allows for dynamic delivery options. The above code is straight from the action mailer basics guide, which you can find here: http://guides.rubyonrails.org/v4.0/action_mailer_basics.html#sending-emails-with-dynamic-delivery-options

With this, it is possible to have different smtp settings for every email you send, or, like in your use case for different sub classes like UserMailer, OtherMailer etc.