Class: ActionMailer::Base

Inherits:
AbstractController::Base
  • Object
show all
Includes:
AbstractController::AssetPaths, AbstractController::Callbacks, AbstractController::Helpers, AbstractController::Layouts, AbstractController::Logger, AbstractController::Rendering, AbstractController::Translation, DeliveryMethods
Defined in:
lib/action_mailer/base.rb

Overview

Action Mailer allows you to send email from your application using a mailer model and views.

Mailer Models

To use Action Mailer, you need to create a mailer model.

$ rails generate mailer Notifier

The generated model inherits from ActionMailer::Base. A mailer model defines methods used to generate an email message. In these methods, you can setup variables to be used in the mailer views, options on the mail itself such as the :from address, and attachments.

class Notifier < ActionMailer::Base
  default from: '[email protected]',
          return_path: '[email protected]'

  def welcome(recipient)
    @account = recipient
    mail(to: recipient.email_address_with_name,
         bcc: ["[email protected]", "Order Watcher <[email protected]>"])
  end
end

Within the mailer method, you have access to the following methods:

  • attachments[]= - Allows you to add attachments to your email in an intuitive manner; attachments['filename.png'] = File.read('path/to/filename.png')

  • attachments.inline[]= - Allows you to add an inline attachment to your email in the same manner as attachments[]=

  • headers[]= - Allows you to specify any header field in your email such as headers['X-No-Spam'] = 'True'. Note, while most fields like To: From: can only appear once in an email header, other fields like X-Anything can appear multiple times. If you want to change a field that can appear multiple times, you need to set it to nil first so that Mail knows you are replacing it and not adding another field of the same name.

  • headers(hash) - Allows you to specify multiple headers in your email such as headers({'X-No-Spam' => 'True', 'In-Reply-To' => '[email protected]'})

  • mail - Allows you to specify email to be sent.

The hash passed to the mail method allows you to specify any header that a Mail::Message will accept (any valid Email header including optional fields).

The mail method, if not passed a block, will inspect your views and send all the views with the same name as the method, so the above action would send the welcome.text.erb view file as well as the welcome.text.html.erb view file in a multipart/alternative email.

If you want to explicitly render only certain templates, pass a block:

mail(to: user.email) do |format|
  format.text
  format.html
end

The block syntax is also useful in providing information specific to a part:

mail(to: user.email) do |format|
  format.text(content_transfer_encoding: "base64")
  format.html
end

Or even to render a special view:

mail(to: user.email) do |format|
  format.text
  format.html { render "some_other_template" }
end

Mailer views

Like Action Controller, each mailer class has a corresponding view directory in which each method of the class looks for a template with its name.

To define a template to be used with a mailing, create an .erb file with the same name as the method in your mailer model. For example, in the mailer defined above, the template at app/views/notifier/welcome.text.erb would be used to generate the email.

Variables defined in the model are accessible as instance variables in the view.

Emails by default are sent in plain text, so a sample view for our model example might look like this:

Hi <%= @account.name %>,
Thanks for joining our service! Please check back often.

You can even use Action Pack helpers in these views. For example:

You got a new note!
<%= truncate(@note.body, length: 25) %>

If you need to access the subject, from or the recipients in the view, you can do that through message object:

You got a new note from <%= message.from %>!
<%= truncate(@note.body, length: 25) %>

Generating URLs

URLs can be generated in mailer views using url_for or named routes. Unlike controllers from Action Pack, the mailer instance doesn’t have any context about the incoming request, so you’ll need to provide all of the details needed to generate a URL.

When using url_for you’ll need to provide the :host, :controller, and :action:

<%= url_for(host: "example.com", controller: "welcome", action: "greeting") %>

When using named routes you only need to supply the :host:

<%= users_url(host: "example.com") %>

You should use the named_route_url style (which generates absolute URLs) and avoid using the named_route_path style (which generates relative URLs), since clients reading the mail will have no concept of a current URL from which to determine a relative path.

It is also possible to set a default host that will be used in all mailers by setting the :host option as a configuration option in config/application.rb:

config.action_mailer.default_url_options = { host: "example.com" }

When you decide to set a default :host for your mailers, then you need to make sure to use the only_path: false option when using url_for. Since the url_for view helper will generate relative URLs by default when a :host option isn’t explicitly provided, passing only_path: false will ensure that absolute URLs are generated.

Sending mail

Once a mailer action and template are defined, you can deliver your message or create it and save it for delivery later:

Notifier.welcome(david).deliver # sends the email
mail = Notifier.welcome(david)  # => a Mail::Message object
mail.deliver                    # sends the email

You never instantiate your mailer class. Rather, you just call the method you defined on the class itself.

Multipart Emails

Multipart messages can also be used implicitly because Action Mailer will automatically detect and use multipart templates, where each template is named after the name of the action, followed by the content type. Each such detected template will be added as a separate part to the message.

For example, if the following templates exist:

  • signup_notification.text.erb

  • signup_notification.text.html.erb

  • signup_notification.text.xml.builder

  • signup_notification.text.yaml.erb

Each would be rendered and added as a separate part to the message, with the corresponding content type. The content type for the entire message is automatically set to multipart/alternative, which indicates that the email contains multiple different representations of the same email body. The same instance variables defined in the action are passed to all email templates.

Implicit template rendering is not performed if any attachments or parts have been added to the email. This means that you’ll have to manually add each part to the email and set the content type of the email to multipart/alternative.

Attachments

Sending attachment in emails is easy:

class ApplicationMailer < ActionMailer::Base
  def welcome(recipient)
    attachments['free_book.pdf'] = File.read('path/to/file.pdf')
    mail(to: recipient, subject: "New account information")
  end
end

Which will (if it had both a welcome.text.erb and welcome.text.html.erb template in the view directory), send a complete multipart/mixed email with two parts, the first part being a multipart/alternative with the text and HTML email parts inside, and the second being a application/pdf with a Base64 encoded copy of the file.pdf book with the filename free_book.pdf.

If you need to send attachments with no content, you need to create an empty view for it, or add an empty body parameter like this:

class ApplicationMailer < ActionMailer::Base
  def welcome(recipient)
    attachments['free_book.pdf'] = File.read('path/to/file.pdf')
    mail(to: recipient, subject: "New account information", body: "")
  end
end

Inline Attachments

You can also specify that a file should be displayed inline with other HTML. This is useful if you want to display a corporate logo or a photo.

class ApplicationMailer < ActionMailer::Base
  def welcome(recipient)
    attachments.inline['photo.png'] = File.read('path/to/photo.png')
    mail(to: recipient, subject: "Here is what we look like")
  end
end

And then to reference the image in the view, you create a welcome.html.erb file and make a call to image_tag passing in the attachment you want to display and then call url on the attachment to get the relative content id path for the image source:

<h1>Please Don't Cringe</h1>

<%= image_tag attachments['photo.png'].url -%>

As we are using Action View’s image_tag method, you can pass in any other options you want:

<h1>Please Don't Cringe</h1>

<%= image_tag attachments['photo.png'].url, alt: 'Our Photo', class: 'photo' -%>

Observing and Intercepting Mails

Action Mailer provides hooks into the Mail observer and interceptor methods. These allow you to register classes that are called during the mail delivery life cycle.

An observer class must implement the :delivered_email(message) method which will be called once for every email sent after the email has been sent.

An interceptor class must implement the :delivering_email(message) method which will be called before the email is sent, allowing you to make modifications to the email before it hits the delivery agents. Your class should make any needed modifications directly to the passed in Mail::Message instance.

Default Hash

Action Mailer provides some intelligent defaults for your emails, these are usually specified in a default method inside the class definition:

class Notifier < ActionMailer::Base
  default sender: '[email protected]'
end

You can pass in any header value that a Mail::Message accepts. Out of the box, ActionMailer::Base sets the following:

  • mime_version: "1.0"

  • charset: "UTF-8",

  • content_type: "text/plain",

  • parts_order: [ "text/plain", "text/enriched", "text/html" ]

parts_order and charset are not actually valid Mail::Message header fields, but Action Mailer translates them appropriately and sets the correct values.

As you can pass in any header, you need to either quote the header as a string, or pass it in as an underscored symbol, so the following will work:

class Notifier < ActionMailer::Base
  default 'Content-Transfer-Encoding' => '7bit',
          content_description: 'This is a description'
end

Finally, Action Mailer also supports passing Proc objects into the default hash, so you can define methods that evaluate as the message is being generated:

class Notifier < ActionMailer::Base
  default 'X-Special-Header' => Proc.new { my_method }

  private

    def my_method
      'some complex call'
    end
end

Note that the proc is evaluated right at the start of the mail message generation, so if you set something in the defaults using a proc, and then set the same thing inside of your mailer method, it will get over written by the mailer method.

It is also possible to set these default options that will be used in all mailers through the default_options= configuration in config/application.rb:

config.action_mailer.default_options = { from: "[email protected]" }

Callbacks

You can specify callbacks using before_action and after_action for configuring your messages. This may be useful, for example, when you want to add default inline attachments for all messages sent out by a certain mailer class:

class Notifier < ActionMailer::Base
  before_action :add_inline_attachment!

  def welcome
    mail
  end

  private

    def add_inline_attachment!
      attachments.inline["footer.jpg"] = File.read('/path/to/filename.jpg')
    end
end

Callbacks in ActionMailer are implemented using AbstractController::Callbacks, so you can define and configure callbacks in the same manner that you would use callbacks in classes that inherit from ActionController::Base.

Note that unless you have a specific reason to do so, you should prefer using before_action rather than after_action in your ActionMailer classes so that headers are parsed properly.

Configuration options

These options are specified on the class level, like ActionMailer::Base.raise_delivery_errors = true

  • default_options - You can pass this in at a class level as well as within the class itself as per the above section.

  • logger - the logger is used for generating information on the mailing run if available. Can be set to nil for no logging. Compatible with both Ruby’s own Logger and Log4r loggers.

  • smtp_settings - Allows detailed configuration for :smtp delivery method:

    • :address - Allows you to use a remote mail server. Just change it from its default “localhost” setting.

    • :port - On the off chance that your mail server doesn’t run on port 25, you can change it.

    • :domain - If you need to specify a HELO domain, you can do it here.

    • :user_name - If your mail server requires authentication, set the username in this setting.

    • :password - If your mail server requires authentication, set the password in this setting.

    • :authentication - If your mail server requires authentication, you need to specify the authentication type here. This is a symbol and one of :plain (will send the password in the clear), :login (will send password Base64 encoded) or :cram_md5 (combines a Challenge/Response mechanism to exchange information and a cryptographic Message Digest 5 algorithm to hash important information)

    • :enable_starttls_auto - When set to true, detects if STARTTLS is enabled in your SMTP server and starts to use it.

    • :openssl_verify_mode - When using TLS, you can set how OpenSSL checks the certificate. This is really useful if you need to validate a self-signed and/or a wildcard certificate. You can use the name of an OpenSSL verify constant (‘none’, ‘peer’, ‘client_once’, ‘fail_if_no_peer_cert’) or directly the constant (OpenSSL::SSL::VERIFY_NONE, OpenSSL::SSL::VERIFY_PEER, …).

  • sendmail_settings - Allows you to override options for the :sendmail delivery method.

    • :location - The location of the sendmail executable. Defaults to /usr/sbin/sendmail.

    • :arguments - The command line arguments. Defaults to -i -t with -f sender@address added automatically before the message is sent.

  • file_settings - Allows you to override options for the :file delivery method.

    • :location - The directory into which emails will be written. Defaults to the application tmp/mails.

  • raise_delivery_errors - Whether or not errors should be raised if the email fails to be delivered.

  • delivery_method - Defines a delivery method. Possible values are :smtp (default), :sendmail, :test, and :file. Or you may provide a custom delivery method object e.g. MyOwnDeliveryMethodClass. See the Mail gem documentation on the interface you need to implement for a custom delivery agent.

  • perform_deliveries - Determines whether emails are actually sent from Action Mailer when you call .deliver on an mail message or on an Action Mailer method. This is on by default but can be turned off to aid in functional testing.

  • deliveries - Keeps an array of all the emails sent out through the Action Mailer with delivery_method :test. Most useful for unit and functional testing.

Defined Under Namespace

Classes: NullMail

Class Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from DeliveryMethods

#wrap_delivery_behavior!

Constructor Details

#initialize(method_name = nil, *args) ⇒ Base

Instantiate a new mailer object. If method_name is not nil, the mailer will be initialized according to the named method. If not, the mailer will remain uninitialized (useful when you only need to invoke the “receive” method, for instance).



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# File 'lib/action_mailer/base.rb', line 493

def initialize(method_name=nil, *args)
  super()
  @_mail_was_called = false
  @_message = Mail.new
  process(method_name, *args) if method_name
end

Class Attribute Details

.mailer_name ⇒ Object 



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# File 'lib/action_mailer/base.rb', line 415

def mailer_name
  @mailer_name ||= anonymous? ? "anonymous" : name.underscore
end

Class Method Details

.controller_path ⇒ Object 



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# File 'lib/action_mailer/base.rb', line 419

def mailer_name
  @mailer_name ||= anonymous? ? "anonymous" : name.underscore
end

.default(value = nil) ⇒ Object Also known as: default_options= 



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# File 'lib/action_mailer/base.rb', line 421

def default(value = nil)
  self.default_params = default_params.merge(value).freeze if value
  default_params
end

.deliver_mail(mail) ⇒ Object

Wraps an email delivery inside of Active Support Notifications instrumentation. This method is actually called by the Mail::Message object itself through a callback when you call :deliver on the Mail::Message, calling deliver_mail directly and passing a Mail::Message will do nothing except tell the logger you sent the email.



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# File 'lib/action_mailer/base.rb', line 453

def deliver_mail(mail) #:nodoc:
  ActiveSupport::Notifications.instrument("deliver.action_mailer") do |payload|
    set_payload_for_mail(payload, mail)
    yield # Let Mail do the delivery actions
  end
end

.receive(raw_mail) ⇒ Object

Receives a raw email, parses it into an email object, decodes it, instantiates a new mailer, and passes the email object to the mailer object’s receive method. If you want your mailer to be able to process incoming messages, you’ll need to implement a receive method that accepts the raw email string as a parameter:

class MyMailer < ActionMailer::Base
  def receive(mail)
    ...
  end
end



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# File 'lib/action_mailer/base.rb', line 441

def receive(raw_mail)
  ActiveSupport::Notifications.instrument("receive.action_mailer") do |payload|
    mail = Mail.new(raw_mail)
    set_payload_for_mail(payload, mail)
    new.receive(mail)
  end
end

.register_interceptor(interceptor) ⇒ Object

Register an Interceptor which will be called before mail is sent. Either a class or a string can be passed in as the Interceptor. If a string is passed in it will be constantized.



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# File 'lib/action_mailer/base.rb', line 410

def register_interceptor(interceptor)
  delivery_interceptor = (interceptor.is_a?(String) ? interceptor.constantize : interceptor)
  Mail.register_interceptor(delivery_interceptor)
end

.register_interceptors(*interceptors) ⇒ Object

Register one or more Interceptors which will be called before mail is sent.



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# File 'lib/action_mailer/base.rb', line 395

def register_interceptors(*interceptors)
  interceptors.flatten.compact.each { |interceptor| register_interceptor(interceptor) }
end

.register_observer(observer) ⇒ Object

Register an Observer which will be notified when mail is delivered. Either a class or a string can be passed in as the Observer. If a string is passed in it will be constantized.



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# File 'lib/action_mailer/base.rb', line 402

def register_observer(observer)
  delivery_observer = (observer.is_a?(String) ? observer.constantize : observer)
  Mail.register_observer(delivery_observer)
end

.register_observers(*observers) ⇒ Object

Register one or more Observers which will be notified when mail is delivered.



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# File 'lib/action_mailer/base.rb', line 390

def register_observers(*observers)
  observers.flatten.compact.each { |observer| register_observer(observer) }
end

.respond_to?(method, include_private = false) ⇒ Boolean

:nodoc:

Returns:

  • (Boolean) 


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# File 'lib/action_mailer/base.rb', line 460

def respond_to?(method, include_private = false) #:nodoc:
  super || action_methods.include?(method.to_s)
end

Instance Method Details

#attachments ⇒ Object

Allows you to add attachments to an email, like so:

mail.attachments['filename.jpg'] = File.read('/path/to/filename.jpg')

If you do this, then Mail will take the file name and work out the mime type set the Content-Type, Content-Disposition, Content-Transfer-Encoding and base64 encode the contents of the attachment all for you.

You can also specify overrides if you want by passing a hash instead of a string:

mail.attachments['filename.jpg'] = {mime_type: 'application/x-gzip',
                                    content: File.read('/path/to/filename.jpg')}

If you want to use a different encoding than Base64, you can pass an encoding in, but then it is up to you to pass in the content pre-encoded, and don’t expect Mail to know how to decode this data:

file_content = SpecialEncode(File.read('/path/to/filename.jpg'))
mail.attachments['filename.jpg'] = {mime_type: 'application/x-gzip',
                                    encoding: 'SpecialEncoding',
                                    content: file_content }

You can also search for specific attachments:

# By Filename
mail.attachments['filename.jpg']   # => Mail::Part object or nil

# or by index
mail.attachments[0]                # => Mail::Part (first attachment)



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# File 'lib/action_mailer/base.rb', line 571

def attachments
  @_message.attachments
end

#headers(args = nil) ⇒ Object

Allows you to pass random and unusual headers to the new Mail::Message object which will add them to itself.

headers['X-Special-Domain-Specific-Header'] = "SecretValue"

You can also pass a hash into headers of header field names and values, which will then be set on the Mail::Message object:

headers 'X-Special-Domain-Specific-Header' => "SecretValue",
        'In-Reply-To' => incoming.message_id

The resulting Mail::Message will have the following in its header:

X-Special-Domain-Specific-Header: SecretValue



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# File 'lib/action_mailer/base.rb', line 533

def headers(args = nil)
  if args
    @_message.headers(args)
  else
    @_message
  end
end

#mail(headers = {}, &block) ⇒ Object

The main method that creates the message and renders the email templates. There are two ways to call this method, with a block, or without a block.

Both methods accept a headers hash. This hash allows you to specify the most used headers in an email message, these are:

  • :subject - The subject of the message, if this is omitted, Action Mailer will ask the Rails I18n class for a translated :subject in the scope of [mailer_scope, action_name] or if this is missing, will translate the humanized version of the action_name

  • :to - Who the message is destined for, can be a string of addresses, or an array of addresses.

  • :from - Who the message is from

  • :cc - Who you would like to Carbon-Copy on this email, can be a string of addresses, or an array of addresses.

  • :bcc - Who you would like to Blind-Carbon-Copy on this email, can be a string of addresses, or an array of addresses.

  • :reply_to - Who to set the Reply-To header of the email to.

  • :date - The date to say the email was sent on.

You can set default values for any of the above headers (except :date) by using the default class method:

class Notifier < ActionMailer::Base
  default from: '[email protected]',
          bcc: '[email protected]',
          reply_to: '[email protected]'
end

If you need other headers not listed above, you can either pass them in as part of the headers hash or use the headers['name'] = value method.

When a :return_path is specified as header, that value will be used as the ‘envelope from’ address for the Mail message. Setting this is useful when you want delivery notifications sent to a different address than the one in :from. Mail will actually use the :return_path in preference to the :sender in preference to the :from field for the ‘envelope from’ value.

If you do not pass a block to the mail method, it will find all templates in the view paths using by default the mailer name and the method name that it is being called from, it will then create parts for each of these templates intelligently, making educated guesses on correct content type and sequence, and return a fully prepared Mail::Message ready to call :deliver on to send.

For example:

class Notifier < ActionMailer::Base
  default from: '[email protected]',

  def welcome
    mail(to: '[email protected]')
  end
end

Will look for all templates at “app/views/notifier” with name “welcome”. If no welcome template exists, it will raise an ActionView::MissingTemplate error.

However, those can be customized:

mail(template_path: 'notifications', template_name: 'another')

And now it will look for all templates at “app/views/notifications” with name “another”.

If you do pass a block, you can render specific templates of your choice:

mail(to: '[email protected]') do |format|
  format.text
  format.html
end

You can even render text directly without using a template:

mail(to: '[email protected]') do |format|
  format.text { render text: "Hello Mikel!" }
  format.html { render text: "<h1>Hello Mikel!</h1>" }
end

Which will render a multipart/alternative email with text/plain and text/html parts.

The block syntax also allows you to customize the part headers if desired:

mail(to: '[email protected]') do |format|
  format.text(content_transfer_encoding: "base64")
  format.html
end



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# File 'lib/action_mailer/base.rb', line 663

def mail(headers = {}, &block)
  @_mail_was_called = true
  m = @_message

  # At the beginning, do not consider class default for content_type
  content_type = headers[:content_type]

  # Call all the procs (if any)
  class_default = self.class.default
  default_values = class_default.merge(class_default) do |k,v|
    v.respond_to?(:to_proc) ? instance_eval(&v) : v
  end

  # Handle defaults
  headers = headers.reverse_merge(default_values)
  headers[:subject] ||= default_i18n_subject

  # Apply charset at the beginning so all fields are properly quoted
  m.charset = charset = headers[:charset]

  # Set configure delivery behavior
  wrap_delivery_behavior!(headers.delete(:delivery_method),headers.delete(:delivery_method_options))

  # Assign all headers except parts_order, content_type and body
  assignable = headers.except(:parts_order, :content_type, :body, :template_name, :template_path)
  assignable.each { |k, v| m[k] = v }

  # Render the templates and blocks
  responses = collect_responses(headers, &block)
  create_parts_from_responses(m, responses)

  # Setup content type, reapply charset and handle parts order
  m.content_type = set_content_type(m, content_type, headers[:content_type])
  m.charset      = charset

  if m.multipart?
    m.body.set_sort_order(headers[:parts_order])
    m.body.sort_parts!
  end

  m
end

#mailer_name ⇒ Object 



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# File 'lib/action_mailer/base.rb', line 515

def mailer_name
  self.class.mailer_name
end

#process(*args) ⇒ Object

:nodoc:



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# File 'lib/action_mailer/base.rb', line 500

def process(*args) #:nodoc:
  lookup_context.skip_default_locale!

  super
  @_message = NullMail.new unless @_mail_was_called
end