Why doesn't Rails pick up my custom mail delivery method? - ruby-on-rails-3

Question

I defined a custom delivery method, and load it in an initializer:
ActionMailer::Base.add_delivery_method :custom, CustomDelivery
I then added config.action_mailer.delivery_method = :custom to both development.rb and production.rb.
But when I want to send an e-mail
UserMailer.authorize(user).deliver
It fails with something related to SMTP (ArgumentError: A sender (Return-Path, Sender or From) required to send a message
from /Users/me/.rbenv/versions/1.9.3-p0/lib/ruby/gems/1.9.1/gems/mail-2.4.4/lib/mail/network/delivery_methods/smtp.rb:99:in deliver!') – which I don't want to use.
Why is it not picking up the custom delivery method?
UPDATE:
When I try from the console, I notice the following:
irb(main):019:0> UserMailer.delivery_method
=> :custom
irb(main):020:0> UserMailer.authorize(user).delivery_method
=> #<Mail::SMTP:0x00000100bdc738 #settings={:address=>"localhost", :port=>25, :domain=>"localhost.localdomain", :user_name=>nil, :password=>nil, :authentication=>nil, :enable_starttls_auto=>true, :openssl_verify_mode=>nil, :ssl=>nil, :tls=>nil}>
(Btw I searched for "SMTP" in my project and there are 0 occurrences)

Answer 1

Configure the action_mailer delivery_method with your custom delivery class:
config.action_mailer.delivery_method = MyCustomDelivery
That class should implement a deliver! instance method that takes an instance of the Mail gem. Something like this:
class MyCustomDelivery
def deliver!(mail)
puts "MAIL FROM: #{mail.from}"
puts "RCPT TO: #{mail.to}"
puts "DATA: #{mail.to_s}"
end
end

Answer 2

Have you configured SMTP via environment.rb ? Here is how mine looks like.
ActionMailer::Base.smtp_settings = {
:domain => 'gmail.com',
:address => 'smtp.gmail.com',
:port => 587,
:tls => true,
:authentication => :plain,
:charset => 'utf-8',
:user_name => ENV['GMAIL_USERNAME'],
:password => ENV['GMAIL_PASSWORD'],
:enable_starttls_auto => true
}