You shouldn't have to re-deploy your application in order to switch SMTP servers, which you may want to do if your provider goes down or starts acting funny, or if you start bumping up against usage limits. This plugin allows you to switch your SMTP settings on the fly. You can even specify them on a per-mail basis if you need that kind of control.

script/plugin install git://github.com/tfe/switchable_smtp.git

The plugin adds a custom_smtp instance variable and method to ActionMailer::Base (to support the old and new way of configuring ActionMailer). To specify different SMTP settings for a mailing, just call this when setting up the mail:

class ApplicationMailer < ActionMailer::Base
  def message(message)
    @recipients = "[email protected]"
    @subject    = "Test"
    @from       = "[email protected]"

    @body[:message] = message

    @custom_smtp = {
      :address => "smtp.sendgrid.net",
      :user_name => "[email protected]",
      :password => "secret",
      :domain=>"example.com",
      :port => "25",
      :authentication => :plain
    }
  end
end

Of course, you'll probably be fetching your custom SMTP settings hash out of the database or something, otherwise there's not much point in using this plugin. On my apps, I'm using the rails-settings gem to keep my settings in the database, then I just do

@custom_smtp = Settings.active_smtp

swapping the active SMTP settings back and forth as necessary.

This is pretty much straight out of this blog post by Jake Varghese. I've just pluginized it and provided some guidelines for using it within your app.

Problems, comments, and pull requests all welcome. Find me on GitHub.

The MIT License

Copyright © 2010 Todd Eichel for Fooala, Inc..

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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