Carrierwave AWS Storage

Use the officially supported AWS-SDK library for S3 storage rather than relying on fog. There are several things going for it:

Full featured, it supports more of the API than Fog
Significantly smaller footprint
Fewer dependencies
Clear documentation

Here is a simple comparison table [07/17/2013]

Library	Disk Space	Lines of Code	Boot Time	Runtime Deps	Develop Deps
fog	28.0M	133469	0.693	9	11
aws-sdk	5.4M	90290	0.098	3	8

Installation

Add this line to your application's Gemfile:

gem 'carrierwave-aws'

Run the bundle command from your shell to install it:

bundle install

Usage

Configure and use it just like you would Fog. The only notable difference is the use of aws_bucket instead of fog_directory, and aws_acl instead of fog_public.

CarrierWave.configure do |config|
  config.storage    = :aws
  config.aws_bucket = ENV.fetch('S3_BUCKET_NAME')
  config.aws_acl    = 'public-read'

  # Optionally define an asset host for configurations that are fronted by a
  # content host, such as CloudFront.
  config.asset_host = 'http://example.com'

  # The maximum period for authenticated_urls is only 7 days.
  config.aws_authenticated_url_expiration = 60 * 60 * 24 * 7

  # Set custom options such as cache control to leverage browser caching
  config.aws_attributes = {
    expires: 1.week.from_now.httpdate,
    cache_control: 'max-age=604800'
  }

  config.aws_credentials = {
    access_key_id:     ENV.fetch('AWS_ACCESS_KEY_ID'),
    secret_access_key: ENV.fetch('AWS_SECRET_ACCESS_KEY'),
    region:            ENV.fetch('AWS_REGION') # Required
  }

  # Optional: Signing of download urls, e.g. for serving private content through CloudFront.
  config.aws_signer = -> (unsigned_url, options) { Aws::CF::Signer.sign_url unsigned_url, options }
end

Custom options for AWS URLs

If you have a custom uploader that specifies additional headers for each URL, please try the following example:

class MyUploader < Carrierwave::Uploader::Base
  # Storage configuration within the uploader supercedes the global CarrierWave
  # config, so either comment out `storage :file`, or remove that line, otherwise
  # AWS will not be used.
  storage :aws

  # You can find a full list of custom headers in AWS SDK documentation on
  # AWS::S3::S3Object
  def download_url(filename)
    url(response_content_disposition: %Q{attachment; filename="#{filename}"})
  end
end

Migrating From Fog

If you migrate from fog your uploader may be configured as storage :fog, simply comment out that line, as in the following example, or remove that specific line.

class MyUploader < Carrierwave::Uploader::Base
  # Storage configuration within the uploader supercedes the global CarrierWave
  # config, so adjust accordingly...

  # Choose what kind of storage to use for this uploader:
  # storage :file
  # storage :fog
  storage :aws


  # More comments below in your file....
end

Another item particular to fog, you may have url(query: {'my-header': 'my-value'}). With carrierwave-aws the query part becomes obsolete, just use a hash of headers. If you skipped the section regarding Usage, you'll want to be sure everything is configured as it's explained in that section as well.

Contributing

In order to run the integration specs you will need to configure some environment variables. A sample file is provided as .env.sample. Copy it over and plug in the appropriate values.

cp .env.sample .env