Use CDN with carrierwave + fog in s3 + cloudfront with rails 3.1

I'm using fog with carrierwave in my website. But the images load very very slowly.

Then I want to speed up loading of images with a CDN.

I have followed this tutorial for create the CDN for images:

http://maketecheasier.com/configure-amazon-s3-as-a-content-delivery-network/2011/06/25

I have now my distribution deployed for images but I don't know how works fine the cdn. I have in initializers/fog.rb the next configuration:

CarrierWave.configure do |config|
  config.fog_credentials = {
    :provider               => 'AWS',
    :aws_access_key_id      => 'key',
    :aws_secret_access_key  => 'key',
    :region                 => 'eu-west-1'
  }
  config.fog_host = "http://da33ii2cvf53u.cloudfront.net" #config.asset_host instead of config.fog_host for new fog gem versions
  config.fog_directory  = 'pin-pro'
  config.fog_public     = false
  #config.fog_attributes = {'Cache-Control' => 'max-age=315576000'} 
end

I dont know if this is correct, but in my local machine it does not works fine for me. I see the image location, is the same route as before:

https://s3-eu-west-1.amazonaws.com/pin-pro/uploads/pins/medium_610cafbe-5d43-4223-ab0e-daa4990863c4.jpg?AWSAccessKeyId=AKIAIDX34WHYKB3ZKFVA&Signature=RwQriNpiRXaTxyfYVvYjsvclUa8%3D&Expires=1333203059

How can I add a CDN to fog file in carrierwave with s3 and cloudfront?

Solution

It looks like you haven't added the line below to your config. You will need to replace the sample address below with your cloudfront address from Amazon.

From the github README: https://github.com/jnicklas/carrierwave

"You can optionally include your CDN host name in the configuration. This is highly recommended, as without it every request requires a lookup of this information"

config.asset_host = "http://c000000.cdn.rackspacecloud.com"