Cloudmailin Rails 3 Mongoid CarrierWave GridFS

carrierwave.rb

# config/initializers/carrierwave.rb
CarrierWave.configure do |config|

  config.storage              = :grid_fs
  config.grid_fs_access_url   = "/files"
  config.grid_fs_database     = Mongoid.database.name

  if Rails.env.production?
    config.grid_fs_database   = ENV['MONGOID_DATABASE'] || Mongoid.database.name
    config.grid_fs_host       = ENV['MONGOID_HOST']
    config.grid_fs_port       = ENV['MONGOID_PORT']
    config.grid_fs_username   = ENV['MONGOID_USERNAME']
    config.grid_fs_password   = ENV['MONGOID_PASSWORD']
  end

end

Gemfile

source :rubygems

gem 'rails',      '3.0.3'

gem 'mongo',      '1.1.5'
gem 'bson',       '1.1.5'
gem 'bson_ext',   '1.1.5'
gem 'mongoid',    '2.0.0.beta.20'
gem 'carrierwave'

incoming_mail.rb

# app/models/incoming_mail.rb
require 'mail'

class IncomingMail
  include Mongoid::Document
  include Mongoid::Timestamps

  # allowed Mail object methods on IncomingMail instance
  ALLOWED_METHODS = %w([] from to cc subject text_part html_part multipart? parts)

  mount_uploader  :raw_mail, RawMailUploader

  def self.new_from_cloudmailin(args)
    raw_mail_file                   = StringIO.new(args[:message])
    raw_mail_file.class.class_eval  { attr_accessor :original_filename, :content_type }
    raw_mail_file.original_filename = args[:subject].present? ? "#{args[:subject].parameterize}.eml" : "untitled.eml"
    raw_mail_file.content_type      = "message/rfc822"

    new(:raw_mail => raw_mail_file)
  end

  ALLOWED_METHODS.each do |method|
    define_method(method) do |args|
      mail.send(method, args)
    end
  end

  private

  def mail
    @mail ||= Mail.new(raw_mail.read)
  end

end

incoming_mails_controller.rb

# app/controllers/incoming_mails_controller.rb
class IncomingMailsController < ApplicationController

  skip_before_filter  :verify_authenticity_token
  before_filter       :verify_signature

  SECRET = ENV['CLOUDMAILIN_SECRET'] || ''

  def create
    message = IncomingMail.new_from_cloudmailin(params)
    if message.save
      render :text => 'success',  :status => 200
    else
      render :text => 'error',    :status => 404
    end
  end

  protected

  def verify_signature
    provided = request.request_parameters.delete(:signature)
    signature = Digest::MD5.hexdigest(request.request_parameters.sort.map{|k,v| v}.join + SECRET)

    if provided != signature
      render :text => "Message signature fail #{provided} != #{signature}", :status => 403, :content_type => Mime::TEXT.to_s
      return false
    end
  end

end

raw_mail_uploader.rb

# app/uploaders/raw_mail_uploader.rb
# encoding: utf-8

class RawMailUploader < CarrierWave::Uploader::Base

  def store_dir
    "raw_mails/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
  end

  # heroku tmp folder
  def cache_dir
    "#{Rails.root}/tmp/raw_mails"
  end

end

routes.rb

# config/routes.rb

# add this to your routes
resources :incoming_mails