Updated attachment_fu to add CloudFront support.

amazon_s3.yml.tpl

@@ -2,13 +2,16 @@ development:
   bucket_name: appname_development
   access_key_id: 
   secret_access_key: 
+  distribution_domain: XXXX.cloudfront.net
 
 test:
   bucket_name: appname_test
   access_key_id: 
   secret_access_key: 
+  distribution_domain: XXXX.cloudfront.net
 
 production:
   bucket_name: appname
   access_key_id: 
   secret_access_key: 
+  distribution_domain: XXXX.cloudfront.net

lib/technoweenie/attachment_fu.rb

@@ -52,6 +52,8 @@ module ActMethods
       #      for the S3 backend.  Setting this sets the :storage to :file_system.
 
       # *  <tt>:storage</tt> - Use :file_system to specify the attachment data is stored with the file system.  Defaults to :db_system.
+      # *  <tt>:cloundfront</tt> - Set to true if you are using S3 storage and want to serve the files through CloudFront.  You will need to
+      #      set a distribution domain in the amazon_s3.yml config file. Defaults to false
       # *  <tt>:bucket_key</tt> - Use this to specify a different bucket key other than :bucket_name in the amazon_s3.yml file.  This allows you to use
       #      different buckets for different models. An example setting would be :image_bucket and the you would need to define the name of the corresponding
       #      bucket in the amazon_s3.yml file.
@@ -80,6 +82,7 @@ def has_attachment(options = {})
         options[:thumbnails]       ||= {}
         options[:thumbnail_class]  ||= self
         options[:s3_access]        ||= :public_read
+        options[:cloudfront]       ||= false
         options[:content_type] = [options[:content_type]].flatten.collect! { |t| t == :image ? Technoweenie::AttachmentFu.content_types : t }.flatten unless options[:content_type].nil?
 
         unless options[:thumbnails].is_a?(Hash)

lib/technoweenie/attachment_fu/backends/s3_backend.rb

@@ -17,22 +17,28 @@ module Backends
       # If you don't already have your access keys, all you need to sign up for the S3 service is an account at Amazon.
       # You can sign up for S3 and get access keys by visiting http://aws.amazon.com/s3.
       #
+      # If you wish to use Amazon CloudFront to serve the files, you can also specify a distibution domain for the bucket.
+      # To read more about CloudFront, visit http://aws.amazon.com/cloudfront
+      #
       # Example configuration (RAILS_ROOT/config/amazon_s3.yml)
       #
       #   development:
       #     bucket_name: appname_development
       #     access_key_id: <your key>
       #     secret_access_key: <your key>
+      #     distribution_domain: XXXX.cloudfront.net
       #
       #   test:
       #     bucket_name: appname_test
       #     access_key_id: <your key>
       #     secret_access_key: <your key>
+      #     distribution_domain: XXXX.cloudfront.net
       #
       #   production:
       #     bucket_name: appname
       #     access_key_id: <your key>
       #     secret_access_key: <your key>
+      #     distribution_domain: XXXX.cloudfront.net
       #
       # You can change the location of the config path by passing a full path to the :s3_config_path option.
       #
@@ -59,6 +65,8 @@ module Backends
       # * <tt>:server</tt> - The server to make requests to. Defaults to <tt>s3.amazonaws.com</tt>.
       # * <tt>:port</tt> - The port to the requests should be made on. Defaults to 80 or 443 if <tt>:use_ssl</tt> is set.
       # * <tt>:use_ssl</tt> - If set to true, <tt>:port</tt> will be implicitly set to 443, unless specified otherwise. Defaults to false.
+      # * <tt>:distribution_domain</tt> - The CloudFront distribution domain for the bucket.  This can either be the assigned
+      #     distribution domain (ie. XXX.cloudfront.net) or a chosen domain using a CNAME. See CloudFront for more details.
       #
       # == Usage
       #
@@ -150,6 +158,16 @@ module Backends
       #
       # Niether <tt>base_path</tt> or <tt>full_filename</tt> include the bucket name as part of the path.
       # You can retrieve the bucket name using the <tt>bucket_name</tt> method.
+      # 
+      # === Accessing CloudFront URLs
+      # 
+      # You can get an object's CloudFront URL using the cloudfront_url accessor.  Using the example from above:
+      # @postcard.cloudfront_url # => http://XXXX.cloudfront.net/photos/1/mexico.jpg
+      #
+      # The resulting url is in the form: http://:distribution_domain/:table_name/:id/:file
+      #
+      # If you set :cloudfront to true in your model, the public_filename will be the CloudFront
+      # URL, not the S3 URL.
       module S3Backend
         class RequiredLibraryNotFoundError < StandardError; end
         class ConfigFileNotFoundError < StandardError; end
@@ -198,6 +216,10 @@ def self.hostname
         def self.port_string
           @port_string ||= (s3_config[:port].nil? || s3_config[:port] == (s3_config[:use_ssl] ? 443 : 80)) ? '' : ":#{s3_config[:port]}"
         end
+
+        def self.distribution_domain
+          @distribution_domain = s3_config[:distribution_domain]
+        end
 
         module ClassMethods
           def s3_protocol
@@ -211,6 +233,10 @@ def s3_hostname
           def s3_port_string
             Technoweenie::AttachmentFu::Backends::S3Backend.port_string
           end
+
+          def cloudfront_distribution_domain
+            Technoweenie::AttachmentFu::Backends::S3Backend.distribution_domain
+          end
         end
 
         # Overwrites the base filename writer in order to store the old filename
@@ -249,7 +275,27 @@ def full_filename(thumbnail = nil)
         def s3_url(thumbnail = nil)
           File.join(s3_protocol + s3_hostname + s3_port_string, bucket_name, full_filename(thumbnail))
         end
-        alias :public_filename :s3_url
+
+        # All public objects are accessible via a GET request to CloudFront. You can generate a
+        # url for an object using the cloudfront_url method.
+        #
+        #   @photo.cloudfront_url
+        #
+        # The resulting url is in the form: <tt>http://:distribution_domain/:table_name/:id/:file</tt> using
+        # the <tt>:distribution_domain</tt> variable set in the configuration parameters in <tt>RAILS_ROOT/config/amazon_s3.yml</tt>.
+        #
+        # The optional thumbnail argument will output the thumbnail's filename (if any).
+        def cloudfront_url(thumbnail = nil)
+          "http://" + cloudfront_distribution_domain + "/" + full_filename(thumbnail)
+        end
+
+        def public_filename(*args)
+          if attachment_options[:cloudfront]
+            cloudfront_url(args)
+          else
+            s3_url(args)
+          end
+        end
 
         # All private objects are accessible via an authenticated GET request to the S3 servers. You can generate an
         # authenticated url for an object like this:
@@ -301,6 +347,10 @@ def s3_hostname
         def s3_port_string
           Technoweenie::AttachmentFu::Backends::S3Backend.port_string
         end
+
+        def cloudfront_distribution_domain
+          Technoweenie::AttachmentFu::Backends::S3Backend.distribution_domain
+        end
 
         protected
           # Called in the after_destroy callback