Can CarrierWave upload to Amazon S3 but serve through CloudFront?

Question

I'm working on a small rails site which allows some users to upload images and others to see them. I started using CarrierWave with S3 as the storage medium and everything worked great but then I wanted to experiment with using CouldFront. I first added a distribution to my S3 bucket and then changed the CarrierWave configuration I was using to this:

CarrierWave.configure do |config|
  config.storage = :fog
  config.fog_credentials = {
    :provider               => 'AWS',                                         # required
    :aws_access_key_id      => ENV['S3_ACCESS_KEY_ID'],                       # required
    :aws_secret_access_key  => ENV['S3_SECRET_ACCESS_KEY'],                   # required
    :region                 => 'eu-west-1',
  }
  config.asset_host = 'http://static.my-domain.com/some-folder'
  config.fog_public     = true                                   # optional, defaults to    true
  config.fog_attributes = {'Cache-Control'=>'max-age=315576000'}  # optional, defaults to {}
end

I should mention that http://static.my-domain.com is a CNAME entry pointing to a CloudFront endpoint (some-id.cloudfront.net). The result is that the pictures are shown correctly, URLs look like this: http://static.my-domain.com/some-folder/uploads/gallery_image/attachment/161/large_image.jpg but whenever I try to upload a photo or for that matter get the size of the uploaded attachment I get the following exception:

Excon::Errors::MovedPermanently: Expected(200) <=> Actual(301 Moved Permanently)
  response => #<Excon::Response:0x007f61fc3d1548 @data={:body=>"", 
  :headers=>{"x-amz-request-id"=>"some-id", "x-amz-id-2"=>"some-id", 
  "Content-Type"=>"application/xml", "Transfer-Encoding"=>"chunked", 
  "Date"=>"Mon, 31 Mar 2014 21:16:45 GMT", "Connection"=>"close", "Server"=>"AmazonS3"}, 
  :status=>301, :remote_ip=>"some-ip"}, @body="", @headers={"x-amz-request-id"=>"some-id", 
  "x-amz-id-2"=>"some-id", "Content-Type"=>"application/xml", 
  "Transfer-Encoding"=>"chunked", "Date"=>"Mon, 31 Mar 2014 21:16:45 GMT", 
  "Connection"=>"close", "Server"=>"AmazonS3"}, @status=301, @remote_ip="some-ip"

Just to add some more info, I tried the following:

• removing the region entry
• using the CloudFront URL directly instead of the CNAME
• specifying the Amazon endpoint (https://s3-eu-west1.amazonaws.com)

but all of them had no effect.

Is there something I'm missing or is it that CarrierWave does not support this at this time?

Answer 1

The answer to the question is YES. The reason why it didn't work with my configuration is that I was missing the fog_directory entry. When I added my asset_host, I removed fog_directory since the CDN urls being generated where malformed. I later found out that this was due to having fog_public set to false. After getting the proper CDN urls, I forgot to add fog_directory back since I could see my images and thought everything was fine. Anyway the correct configuration is:

CarrierWave.configure do |config|
  config.storage = :fog
  config.fog_credentials = {
    :provider               => 'AWS',                                         # required
    :aws_access_key_id      => ENV['S3_ACCESS_KEY_ID'],                       # required
    :aws_secret_access_key  => ENV['S3_SECRET_ACCESS_KEY'],                   # required
    :region                 => 'eu-west-1'
  }

  config.fog_directory  = '-bucket-name-/-some-folder-'
  config.asset_host = 'https://static.my-domain.com/-some-folder-'
  config.fog_public     = true                                   # optional, defaults to true
  config.fog_attributes = {'Cache-Control'=>'max-age=315576000'}  # optional, defaults to {}
end

Answer 2

Try setting :asset_host in your Uploader like so:

class ScreenshotUploader < CarrierWave::Uploader::Base
  storage :fog 

  # Configure uploads to be stored in a public Cloud Files container
  def fog_directory
    'my_public_container'
  end

  # Configure uploads to be delivered over Rackspace CDN
  def asset_host
   "c000000.cdn.rackspacecloud.com"
  end
end

Inspired from https://github.com/carrierwaveuploader/carrierwave/wiki/How-to%3A-Store-private-public-uploads-in-different-Cloud-Files-Containers-with-Fog