require 'active_support/descendants_tracker' module ActionMailer module Previews #:nodoc: extend ActiveSupport::Concern included do # Set the location of mailer previews through app configuration: # # config.action_mailer.preview_path = "#{Rails.root}/lib/mailer_previews" # class_attribute :preview_path, instance_writer: false end end class Preview extend ActiveSupport::DescendantsTracker class << self # Returns all mailer preview classes def all load_previews if descendants.empty? descendants end # Returns the mail object for the given email name def call(email) preview = self.new preview.public_send(email) end # Returns all of the available email previews def emails public_instance_methods(false).map(&:to_s).sort end # Returns true if the email exists def email_exists?(email) emails.include?(email) end # Returns true if the preview exists def exists?(preview) all.any?{ |p| p.preview_name == preview } end # Find a mailer preview by its underscored class name def find(preview) all.find{ |p| p.preview_name == preview } end # Returns the underscored name of the mailer preview without the suffix def preview_name name.sub(/Preview$/, '').underscore end protected def load_previews #:nodoc: Dir["#{preview_path}/**/*_preview.rb"].each{ |file| require_dependency file } end def preview_path #:nodoc: Base.preview_path end end end end