This class control the incoming mails, parse the information in it, extract the attached picture and upload it to amazon s3 using paperclip, A monkey patch hack is needed to solve a inconsistence between paperclip and heroku/cloudmailin

Incoming_mails_controller.rb

class IncomingMailsController < ApplicationController
  skip_before_filter :verify_authenticity_token 
  
  def create    
    message = Mail.new(params[:message])    
    user = User.where(:email=>message.from).first    

    if !message.attachments.first.nil?           
      post = Post.new(
        :title => message.subject, 
        :photo => parse_photo(message), 
        :user  => user)
      
      if post.save
        render :text => 'success', :status => 200 
      else
        render :text => 'The picture was to big!', :status => 404
      end
    else
      render :text => 'Ups, You forget to attach a picture to the mail', :status => 404
    end        
  end

  private
  # We need that the file-like object that we are going to use
  # for paperclip respond to original_filename and content_type
  # so we create then wiht class eval as attr_accessor.
  #
  # Due that we are deploying in heroku we can not write to disk.
  def parse_photo message
    attachment = message.attachments.first
    file = StringIO.new(attachment.decoded)
    file.class.class_eval { attr_accessor :original_filename, :content_type }
    file.original_filename = attachment.filename
    file.content_type = attachment.mime_type

    file
  end
  
end