Amazon SES raise SMTP Error `Net::SMTPFatalError (554 Transaction failed: Empty address)`

[ippachi]

When using hanami/mailer with Amazon SES, this raises Net::SMTPFatalError (554 Transaction failed: Empty address) because of the empty Return-Path header.

Hanami::Mailer.new seems to set nil to Return-Path and send an email with empty Return-Path finally.
I think Hanami::Mailer shouldn't send Return-Path if that is nil.

I don't know that point out is correct because I'm not familiar with mail protocol.
What do you think about that?

[Luca Guidi]

@ippachi Do you have an example of the failing Mailer? I can't reproduce the problem with unit tests.

[ippachi]

require 'hanami/mailer'

Hanami::Mailer.configure do
  delivery_method :smtp,
    address:              "email-smtp.ap-northeast-1.amazonaws.com",
    port:                 587,
    user_name:            ENV['AWS_SES_USERNAME'],
    password:             ENV['AWS_SES_PASSWORD'],
    authentication:       "plain",
    enable_starttls_auto: true
end.load!

class WelcomeMailer
  include Hanami::Mailer

  from '[e-mail]'
  to '[e-mail]'
  template 'test'

  subject 'Welcome'

  def self.templates(*); end
end

WelcomeMailer.deliver

This code raises 554 Transaction failed: Empty address (Net::SMTPFatalError).
But I have been able to confirm in Aws SES only. I don't know that problem has occurred on other mail servers.

[ippachi]

module Hanami
  module Mailer
    def build
      Mail.new.tap do |m|
        # m.return_path = __dsl(:return_path)
        m.from     = __dsl(:from)
        m.to       = __dsl(:to)
        m.cc       = __dsl(:cc)
        m.bcc      = __dsl(:bcc)
        m.reply_to = __dsl(:reply_to)
        m.subject  = __dsl(:subject)

        m.charset   = charset
        m.html_part = __part(:html)
        m.text_part = __part(:txt)

        m.delivery_method(*Hanami::Mailer.configuration.delivery_method)
      end
    end
  end
end

This is my hotfix code. This hotfix works well. (I don't need to specify return-path)
My idea is that checking is return-path nil before assigned m.return_path like below code.

def build
      Mail.new.tap do |m|
        unless __dsl(:return_path).nil?
          m.return_path = __dsl(:return_path)
        end
        m.from     = __dsl(:from)
        m.to       = __dsl(:to)
        m.cc       = __dsl(:cc)
        m.bcc      = __dsl(:bcc)
        m.reply_to = __dsl(:reply_to)
        m.subject  = __dsl(:subject)

        m.charset   = charset
        m.html_part = __part(:html)
        m.text_part = __part(:txt)

        m.delivery_method(*Hanami::Mailer.configuration.delivery_method)
      end