Overview.

A plugin for the Merb framework that allows you to send email from Merb application.
It separates email composition and sending into micro MVC: you may have mail controllers
that compose complex emails, emails have their own views and models (models use MailFactory
library and non-persistable).

Installation.

(sudo) gem install merb-mailer

It will install mailfactory gem and mime-types that mailfactory depends on.

Configuration.

In init.rb, include a dependency on ‘merb-mailer’.With versions of Merb earlier than 0.9.3 Merb::Mailer may raise a NameError when configuration is put into
after_app_loads block. Put it to the very end of your init file and it should work. This problem does not exist in Git HEAD.

Using SMTP.

  Merb::Mailer.config = {
    :host   => 'smtp.yourserver.com',
    :port   => '25',
    :user   => 'user',
    :pass   => 'pass',
    :auth   => :plain # :plain, :login, :cram_md5, the default is no auth
    :domain => "localhost.localdomain" # the HELO domain provided by the client to the server
  }

Using Gmail SMTP.

Configuration example for Gmail SMTP:

Merb::Mailer.config = {
  :host   => 'smtp.gmail.com',
  :port   => '587',
  :user   => 'user@gmail.com',
  :pass   => 'pass',
  :auth   => :plain
}

• require smtp_tls
• Use :text option instead of :body when deliver.

m = Merb::Mailer.new :to      => 'foo@bar.com',
                     :from    => 'bar@foo.com',
                     :subject => 'Welcome to whatever!',
                     :text    => partial(:sometemplate)
m.deliver!

Using Sendmail.

Sending mail from controllers.

Merb mailer plugin has idea of separation of mailer logic from mailer templates
to the point mailers in Merb have own tiny MVC architecture for emails.
Your application controllers usually delegate email sending to mail controllers
instead of doing it on their own.

To send your mail using mail controller you use send_mail method that
takes mail controller class, action name, mail parameters and action parameters.
params hash with action parameters mentioned above is accessible in mail controller’s
action.

def send_activation_email(person)
	send_mail PeopleMailer, :activation, {
		:from => "no-reply@example.com",
		:to => person.email,
		:subject => "Please activate your account"
	}, {
		:name => person.name
	}
end

Mail parameters you can specify:

• :to
• :from
• :replyto
• :subject
• :body
• :cc

Example of Merb controller:

class ProductDeliveryMailer < Merb::MailController
  def notify_on_delivery
	  @delivery_info = params[:details]
		# you can access @delivery_info in rendered template
    render_mail
  end  
end

Mail templates are kept under app/views/mail controller name/template name just like with regular controllers.
Content types in template name may be either text or html, like in
app/mailers/views/user_mailer/hello.text.erb for the mailer controller above:

Hello <%= params[:name] %>

render_mail works similarly to render method. It takes either action as Symbol or Hash of
template paths. Most of the times naming templates the same as your actions works so you
can just use

class ResourceShortageMailer < Merb::MailController
  def notify_on_disk_space_shortage
    render_mail
  end  
end

and it will render app/mailers/views/resource_shortage_mailer/notify_on_disk_space_shortage.text.erb.

If you need to specify template path explicitly, you can do it for both text and html:

class ResourceShortageMailer < Merb::MailController
  def notify_on_disk_space_shortage
    render_mail :action => { :html => :hdd_space_shortage_detailed, :text => :hdd_space_shortage }
  end  
end

This will look for app/mailers/views/resource_shortage_mailer/hdd_space_shortage_detailed.html.erb for
html and app/mailers/views/resource_shortage_mailer/hdd_space_shortage.text.erb for text.

See render_mail documentation
for more examples, this method has a lot of options how you can use it.

Using Merb mailer to send emails outside of controllers.

There are two ways of sending email with merb-mailer: using mail controllers and using just Merb::Mailer.
Here is example of using Merb::Mailer to deliver emails from model hook.

class Person
include DataMapper::Resource

after :create, :deliver_activation_notification

body_string = <<-EOS
Please activate your account…
EOS

Merb::Mailer.new(
:from => “no-reply@webapp.com”,
:to => self.email,
:subject => “Activate your account”,
:body => body_string
).deliver!
end
end

In this example we deliver signup activation email from model hook.
Keep in mind that Merb::Mailer is a thin wrapper around MailFactory that
provides several ways of sending emails. You can access plain text email body
with text method of mailer and html body with html method, respectively.

Testing mailers.

A word of warning: merb-mailer does not raise exceptions when your template is not found.
So if nothing gets rendered, check merb test environment log to make sure you have no
warnings. If it is considered a bug, file a ticket to LightHouse.

Make sure you use test sending method so emails won’t be sent on each tests run.
Add this line to your test file:

Merb::Mailer.delivery_method = :test_send

Here is an example of helper to test mailers themselves:

def describe_mail(mailer, template, &block)
  describe "/#{mailer.to_s.downcase}/#{template}" do
    before :each do
      @mailer_class, @template = mailer, template
      @assigns = {}
    end

def deliver(send_params={}, mail_params={})
mail_params = {:from => “from@example.com”, :to => “to@example.com”, :subject => “Please activate your account”}.merge(mail_params)
@mailer_class.new(send_params).dispatch_and_deliver @template.to_sym, mail_params
@mail = Merb::Mailer.deliveries.last
end
instance_eval &block
end
end

Mailer controller specs may look like this then:

require File.join(File.dirname(__FILE__),'..','spec_helper')

describe_mail UserMailer, :hello do

  it “sends activation” do

    deliver :name => “Jamie”

    @mail.text.should == “Please activate your account, Jamie”

  end

end

Most of mail controller specs verify delivered email headers like
to, subject or body. To access deliveries you use Merb::Mailer.deliveries
array.

It is recommended to clear it on test setup first:

require File.join(File.dirname(__FILE__),'..','spec_helper')

describe_mail UserMailer, :hello do
  before :each do
    Merb::Mailer.deliveries.clear
	end
end

To do actual matching you can create a helper like this:

def last_delivered_email
  Merb::Mailer.deliveries.last
end

and use it like this:

last_delivered_email.from.first.should == "no-reply@webapp.com"

Note that MailFactory that is used by merb-mailer under the covers returns headers
as Arrays. This is why we used from.first in example above.