Cloudfront + Carrierwave - ruby-on-rails

Question

So this seems like it should be quite easy... everyone is saying just to use config.asset_host. When I set that though, all the links inside my app still point to S3.
CarrierWave.configure do |config|
config.storage = :fog
config.fog_credentials = {
:provider => 'AWS',
:aws_access_key_id => AWS_ACCESS_KEY_ID,
:aws_secret_access_key => AWS_SECRET_ACCESS_KEY,
:region => 'us-east-1'
}
config.fog_authenticated_url_expiration = 3.hours
config.asset_host = "http://xyz123.cloudfront.net"
config.fog_directory = S3_BUCKET_NAME
config.fog_public = false
config.fog_attributes = {
'Cache-Control' => "max-age=#{1.year.to_i}"
}
end
here is how I call my files...
image_tag book.attachments.first.filename.file.authenticated_url(:thumb175)
It looks to me like public_url prepends the proper host, but it takes 0 arguments... so how am I supposed to pass the proper response-content-disposition and response-content-type and the link expire time?

Answer 1

I had the same problem and spent far too long figuring out the answer! It turns out that when you set fog_public = false CarrierWave will ignore config.asset_host. You can demo this by setting config.fog_public = true: your URLs will now be CloudFront URLs rather than S3 URLs. This issue has been raised previously:
https://github.com/carrierwaveuploader/carrierwave/issues/1158
https://github.com/carrierwaveuploader/carrierwave/issues/1215
In a recent project I was happy using CarrierWave to handle uploads to S3, but wanted it to return a signed CloudFront URL when using Model.attribute_url. I came up with the following (admittedly ugly) workaround that I hope others can benefit from or improve upon:
Add the 'cloudfront-signer' gem to your project and configure it per the instructions. Then add the following override of /lib/carrierwave/uploader/url.rb in a new file in config/initializers (note the multiple insertions of AWS::CF::Signer.sign_url):
module CarrierWave
module Uploader
module Url
extend ActiveSupport::Concern
include CarrierWave::Uploader::Configuration
include CarrierWave::Utilities::Uri
##
# === Parameters
#
# [Hash] optional, the query params (only AWS)
#
# === Returns
#
# [String] the location where this file is accessible via a url
#
def url(options = {})
if file.respond_to?(:url) and not file.url.blank?
file.method(:url).arity == 0 ? AWS::CF::Signer.sign_url(file.url) : AWS::CF::Signer.sign_url(file.url(options))
elsif file.respond_to?(:path)
path = encode_path(file.path.gsub(File.expand_path(root), ''))
if host = asset_host
if host.respond_to? :call
AWS::CF::Signer.sign_url("#{host.call(file)}#{path}")
else
AWS::CF::Signer.sign_url("#{host}#{path}")
end
else
AWS::CF::Signer.sign_url((base_path || "") + path)
end
end
end
end # Url
end # Uploader
end # CarrierWave
Then override /lib/carrierwave/storage/fog.rb by adding the following to the bottom of the same file:
require "fog"
module CarrierWave
module Storage
class Fog < Abstract
class File
include CarrierWave::Utilities::Uri
def url
# Delete 'if statement' related to fog_public
public_url
end
end
end
end
end
Lastly, in config/initializers/carrierwave.rb:
config.asset_host = "http://d12345678.cloudfront.net"
config.fog_public = false
That's it. You can now use Model.attribute_url and it will return a signed CloudFront URL to a private file uploaded by CarrierWave to your S3 bucket.

Answer 2

I think you found this for yourself, but public urls will not expire. If you want that you'll need to use authenticated urls. For public urls I think you can simply get the url and append whatever query params you would like, at least for now. If that works well for you, we can certainly see about patching things to do the right thing.