175 lines
5.5 KiB
Text
175 lines
5.5 KiB
Text
= Action Mailer -- Easy email delivery and testing
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Action Mailer is a framework for designing email service layers. These layers
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are used to consolidate code for sending out forgotten passwords, welcome
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wishes on signup, invoices for billing, and any other use case that requires
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a written notification to either a person or another system.
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Action Mailer is in essence a wrapper around Action Controller and the
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Mail gem. It provides a way to make emails using templates in the same
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way that Action Controller renders views using templates.
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Additionally, an Action Mailer class can be used to process incoming email,
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such as allowing a blog to accept new posts from an email (which could even
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have been sent from a phone).
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== Sending emails
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The framework works by initializing any instance variables you want to be
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available in the email template, followed by a call to +mail+ to deliver
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the email.
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This can be as simple as:
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class Notifier < ActionMailer::Base
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default from: 'system@loudthinking.com'
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def welcome(recipient)
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@recipient = recipient
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mail(to: recipient,
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subject: "[Signed up] Welcome #{recipient}")
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end
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end
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The body of the email is created by using an Action View template (regular
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ERB) that has the instance variables that are declared in the mailer action.
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So the corresponding body template for the method above could look like this:
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Hello there,
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Mr. <%= @recipient %>
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Thank you for signing up!
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If the recipient was given as "david@loudthinking.com", the email
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generated would look like this:
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Date: Mon, 25 Jan 2010 22:48:09 +1100
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From: system@loudthinking.com
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To: david@loudthinking.com
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Message-ID: <4b5d84f9dd6a5_7380800b81ac29578@void.loudthinking.com.mail>
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Subject: [Signed up] Welcome david@loudthinking.com
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Mime-Version: 1.0
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Content-Type: text/plain;
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charset="US-ASCII";
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Content-Transfer-Encoding: 7bit
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Hello there,
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Mr. david@loudthinking.com
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Thank you for signing up!
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In order to send mails, you simply call the method and then call +deliver_now+ on the return value.
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Calling the method returns a Mail Message object:
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message = Notifier.welcome("david@loudthinking.com") # => Returns a Mail::Message object
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message.deliver_now # => delivers the email
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Or you can just chain the methods together like:
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Notifier.welcome("david@loudthinking.com").deliver_now # Creates the email and sends it immediately
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== Setting defaults
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It is possible to set default values that will be used in every method in your
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Action Mailer class. To implement this functionality, you just call the public
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class method +default+ which you get for free from <tt>ActionMailer::Base</tt>.
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This method accepts a Hash as the parameter. You can use any of the headers,
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email messages have, like +:from+ as the key. You can also pass in a string as
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the key, like "Content-Type", but Action Mailer does this out of the box for you,
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so you won't need to worry about that. Finally, it is also possible to pass in a
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Proc that will get evaluated when it is needed.
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Note that every value you set with this method will get overwritten if you use the
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same key in your mailer method.
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Example:
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class AuthenticationMailer < ActionMailer::Base
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default from: "awesome@application.com", subject: Proc.new { "E-mail was generated at #{Time.now}" }
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.....
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end
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== Receiving emails
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To receive emails, you need to implement a public instance method called
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+receive+ that takes an email object as its single parameter. The Action Mailer
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framework has a corresponding class method, which is also called +receive+, that
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accepts a raw, unprocessed email as a string, which it then turns into the email
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object and calls the receive instance method.
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Example:
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class Mailman < ActionMailer::Base
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def receive(email)
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page = Page.find_by(address: email.to.first)
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page.emails.create(
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subject: email.subject, body: email.body
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)
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if email.has_attachments?
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email.attachments.each do |attachment|
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page.attachments.create({
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file: attachment, description: email.subject
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})
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end
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end
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end
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end
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This Mailman can be the target for Postfix or other MTAs. In Rails, you would use
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the runner in the trivial case like this:
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rails runner 'Mailman.receive(STDIN.read)'
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However, invoking Rails in the runner for each mail to be received is very
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resource intensive. A single instance of Rails should be run within a daemon, if
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it is going to process more than just a limited amount of email.
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== Configuration
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The Base class has the full list of configuration options. Here's an example:
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ActionMailer::Base.smtp_settings = {
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address: 'smtp.yourserver.com', # default: localhost
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port: '25', # default: 25
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user_name: 'user',
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password: 'pass',
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authentication: :plain # :plain, :login or :cram_md5
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}
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== Download and installation
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The latest version of Action Mailer can be installed with RubyGems:
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$ gem install actionmailer
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Source code can be downloaded as part of the Rails project on GitHub
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* https://github.com/rails/rails/tree/master/actionmailer
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== License
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Action Mailer is released under the MIT license:
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* http://www.opensource.org/licenses/MIT
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== Support
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API documentation is at
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* http://api.rubyonrails.org
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Bug reports can be filed for the Ruby on Rails project here:
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* https://github.com/rails/rails/issues
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Feature requests should be discussed on the rails-core mailing list here:
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* https://groups.google.com/forum/?fromgroups#!forum/rubyonrails-core
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