Most of the Rails sites I have been developing lately have been using a plugin called attachment_fu by Rick Olson - one of the core developers of Rails. attachment_fu is easily and effortless - allowing me to add the ability to add "attachments" or uploads to any model within my application. After reading the excellent tutorial by Mike Clark, I was up and running in no time.

class Download < ActiveRecord::Base
  has_attachment :storage => :file_system,
    :path_prefix => "/public/downloads/",
    :max_size => 30.megabytes
end

And in my view(s):

 
<td class="input_field">
  < %= f.file_field :uploaded_data %>
</td>
 

But after a while, downloads started to build up in size consumed, and backups were using valuable bandwidth (since backups moved the files off the server). I remember reading on the excellent tutorial by Mike Clark how easy it looked to change the storage to use Amazon's Simple Storage Service (S3). I installed the AWS::S3 Ruby library, and even played around with s3sh - the interactive shell utility that comes with the AWS::S3 library.

Revisiting the tutorial, I changed my Download model to:

class Download < ActiveRecord::Base
  has_attachment :storage => :s3, :max_size => 30.megabytes
end

And created my config/amazon_s3.yml configuration file:

 
production:
  bucket_name: my_bucket
  access_key_id: XXXXXX
  secret_access_key: XXXXXX
 

After a few quick tests, everything was working perfectly. Now the only problem I had was moving the existing downloads into the S3 account. I figured the best way to go was to integrate a rake task to help me out.

desc "Move all downloads to Amazon's S3"
task :move_to_s3 => [:environment] do |e|
  require 'rubygems'
  require 'aws/s3'

  AWS::S3::Base.establish_connection!(
    :access_key_id     => 'XXXXXX',
    :secret_access_key => 'XXXXXXX'
  )

  Download.find(:all).each do |d|
    AWS::S3::S3Object.store("/path_on_s3/to_new/download",
      open("/path/to/where/current/file/is_located"),
      'my_bucket',
      :access => :public_read)
  end
end

All done. Total cost to move all this stuff over to S3 was about $.10 .

Also, if you're interested, check out S3Fox - a plugin for Mozilla Firefox that allows you to browse, organize, and store your files into your S3 account - all through Firefox.