Ability to set permissions on a per style bases.

Example:
  has_attached_file :image,
    :bucket => "testing",
    :path => ":attachment/:style/:basename.:extension"
    :s3_permissions => {
      :original => :private
    },
    :styles => {
      :thumb => '80x80>'
    }

The above will allow public read access on :thumb but require credentials for :original.

Example of setting default to private:
  has_attached_file :image,
    :bucket => "testing",
    :path => ":attachment/:style/:basename.:extension"
    :s3_permissions => :private
    :styles => {
      :thumb => '80x80>'
    }

The above will set all to private

Closes #398

lib/paperclip/storage/s3.rb

@@ -27,6 +27,14 @@ module Paperclip
     #   policies that S3 provides (more information can be found here:
     #   http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?RESTAccessPolicy.html)
     #   The default for Paperclip is :public_read.
+    #
+    #   You can set permission on a per style bases by doing the following:
+    #     :s3_permissions => {
+    #       :original => :private
+    #     }
+    #   Or globaly:
+    #     :s3_permissions => :private
+    #
     # * +s3_protocol+: The protocol for the URLs generated to your S3 assets. Can be either
     #   'http' or 'https'. Defaults to 'http' when your :s3_permissions are :public_read (the
     #   default), and 'https' when your :s3_permissions are anything else.
@@ -72,8 +80,11 @@ module Paperclip
           @bucket         = @options[:bucket]         || @s3_credentials[:bucket]
           @bucket         = @bucket.call(self) if @bucket.is_a?(Proc)
           @s3_options     = @options[:s3_options]     || {}
-          @s3_permissions = @options[:s3_permissions] || :public_read
-          @s3_protocol    = @options[:s3_protocol]    || (@s3_permissions == :public_read ? 'http' : 'https')
+          @s3_permissions = set_permissions(@options[:s3_permissions])
+          @s3_protocol    = @options[:s3_protocol]    ||
+            Proc.new do |style|
+              (@s3_permissions[style.to_sym] || @s3_permissions[:default]) == :public_read ? 'http' : 'https'
+            end
           @s3_headers     = @options[:s3_headers]     || {}
           @s3_host_alias  = @options[:s3_host_alias]
           @s3_host_alias  = @s3_host_alias.call(self) if @s3_host_alias.is_a?(Proc)
@@ -88,13 +99,13 @@ module Paperclip
           ))
         end
         Paperclip.interpolates(:s3_alias_url) do |attachment, style|
-          "#{attachment.s3_protocol}://#{attachment.s3_host_alias}/#{attachment.path(style).gsub(%r{^/}, "")}"
+          "#{attachment.s3_protocol(style)}://#{attachment.s3_host_alias}/#{attachment.path(style).gsub(%r{^/}, "")}"
         end unless Paperclip::Interpolations.respond_to? :s3_alias_url
         Paperclip.interpolates(:s3_path_url) do |attachment, style|
-          "#{attachment.s3_protocol}://s3.amazonaws.com/#{attachment.bucket_name}/#{attachment.path(style).gsub(%r{^/}, "")}"
+          "#{attachment.s3_protocol(style)}://s3.amazonaws.com/#{attachment.bucket_name}/#{attachment.path(style).gsub(%r{^/}, "")}"
         end unless Paperclip::Interpolations.respond_to? :s3_path_url
         Paperclip.interpolates(:s3_domain_url) do |attachment, style|
-          "#{attachment.s3_protocol}://#{attachment.bucket_name}.s3.amazonaws.com/#{attachment.path(style).gsub(%r{^/}, "")}"
+          "#{attachment.s3_protocol(style)}://#{attachment.bucket_name}.s3.amazonaws.com/#{attachment.path(style).gsub(%r{^/}, "")}"
         end unless Paperclip::Interpolations.respond_to? :s3_domain_url
         Paperclip.interpolates(:asset_host) do |attachment, style|
           "#{attachment.path(style).gsub(%r{^/}, "")}"
@@ -102,13 +113,22 @@ module Paperclip
       end
 
       def expiring_url(time = 3600, style_name = default_style)
-        AWS::S3::S3Object.url_for(path(style_name), bucket_name, :expires_in => time, :use_ssl => (s3_protocol == 'https'))
+        AWS::S3::S3Object.url_for(path(style_name), bucket_name, :expires_in => time, :use_ssl => (s3_protocol(style_name) == 'https'))
       end
 
       def bucket_name
         @bucket
       end
 
+      def set_permissions permissions
+        if permissions.is_a?(Hash)
+          permissions[:default] = permissions[:default] || :public_read
+        else
+          permissions = { :default => permissions || :public_read }
+        end
+        permissions
+      end
+
       def s3_host_alias
         @s3_host_alias
       end
@@ -126,9 +146,13 @@ module Paperclip
         end
       end
 
-      def s3_protocol
+      def s3_protocol(style)
+        if @s3_protocol.is_a?(Proc)
+          @s3_protocol.call(style)
+        else
           @s3_protocol
         end
+      end
 
       # Returns representation of the data of the file assigned to the given
       # style, in the format most representative of the current storage.
@@ -156,7 +180,7 @@ module Paperclip
                                     file,
                                     bucket_name,
                                     {:content_type => file.content_type.to_s.strip,
-                                     :access => @s3_permissions,
+                                     :access => (@s3_permissions[style] || @s3_permissions[:default]),
                                     }.merge(@s3_headers))
           rescue AWS::S3::NoSuchBucket => e
             create_bucket

test/storage_test.rb

@@ -216,6 +216,7 @@ class StorageTest < Test::Unit::TestCase
                       :production   => { :bucket => "prod_bucket" },
                       :development  => { :bucket => "dev_bucket" }
                     },
+                    :s3_permissions => :private,
                     :s3_host_alias => "something.something.com",
                     :path => ":attachment/:style/:basename.:extension",
                     :url => ":s3_alias_url"
@@ -225,10 +226,10 @@ class StorageTest < Test::Unit::TestCase
       @dummy = Dummy.new
       @dummy.avatar = StringIO.new(".")
 
-      AWS::S3::S3Object.expects(:url_for).with("avatars/original/stringio.txt", "prod_bucket", { :expires_in => 3600, :use_ssl => false })
+      AWS::S3::S3Object.expects(:url_for).with("avatars/original/stringio.txt", "prod_bucket", { :expires_in => 3600, :use_ssl => true })
       @dummy.avatar.expiring_url
 
-      AWS::S3::S3Object.expects(:url_for).with("avatars/thumb/stringio.txt", "prod_bucket", { :expires_in => 1800, :use_ssl => false })
+      AWS::S3::S3Object.expects(:url_for).with("avatars/thumb/stringio.txt", "prod_bucket", { :expires_in => 1800, :use_ssl => true })
       @dummy.avatar.expiring_url(1800, :thumb)
     end
 
@@ -433,6 +434,132 @@ class StorageTest < Test::Unit::TestCase
     end
   end
   
+  context "S3 Permissions" do
+    context "defaults to public-read" do
+      setup do
+        rebuild_model :storage => :s3,
+                      :bucket => "testing",
+                      :path => ":attachment/:style/:basename.:extension",
+                      :s3_credentials => {
+                        'access_key_id' => "12345",
+                        'secret_access_key' => "54321"
+                      }
+      end
+
+      context "when assigned" do
+        setup do
+          @file = File.new(File.join(File.dirname(__FILE__), 'fixtures', '5k.png'), 'rb')
+          @dummy = Dummy.new
+          @dummy.avatar = @file
+        end
+
+        teardown { @file.close }
+
+        context "and saved" do
+          setup do
+            AWS::S3::Base.stubs(:establish_connection!)
+            AWS::S3::S3Object.expects(:store).with(@dummy.avatar.path,
+                                                 anything,
+                                                 'testing',
+                                                 :content_type => 'image/png',
+                                                 :access => :public_read)
+            @dummy.save
+          end
+
+          should "succeed" do
+            assert true
+          end
+        end
+      end
+    end
+
+    context "string permissions set" do
+      setup do
+        rebuild_model :storage => :s3,
+                      :bucket => "testing",
+                      :path => ":attachment/:style/:basename.:extension",
+                      :s3_credentials => {
+                        'access_key_id' => "12345",
+                        'secret_access_key' => "54321"
+                      },
+                      :s3_permissions => 'private'
+      end
+    
+      context "when assigned" do
+        setup do
+          @file = File.new(File.join(File.dirname(__FILE__), 'fixtures', '5k.png'), 'rb')
+          @dummy = Dummy.new
+          @dummy.avatar = @file
+        end
+    
+        teardown { @file.close }
+    
+        context "and saved" do
+          setup do
+            AWS::S3::Base.stubs(:establish_connection!)
+            AWS::S3::S3Object.expects(:store).with(@dummy.avatar.path,
+                                                   anything,
+                                                   'testing',
+                                                   :content_type => 'image/png',
+                                                   :access => 'private')
+            @dummy.save
+          end
+    
+          should "succeed" do
+            assert true
+          end
+        end
+      end
+    end
+    
+    context "hash permissions set" do
+      setup do
+        rebuild_model :storage => :s3,
+                      :bucket => "testing",
+                      :path => ":attachment/:style/:basename.:extension",
+                      :styles => {
+                         :thumb => "80x80>"
+                      },
+                      :s3_credentials => {
+                        'access_key_id' => "12345",
+                        'secret_access_key' => "54321"
+                      },
+                      :s3_permissions => {
+                        :original => 'private',
+                        :thumb => 'public-read'
+                      }
+      end
+    
+      context "when assigned" do
+        setup do
+          @file = File.new(File.join(File.dirname(__FILE__), 'fixtures', '5k.png'), 'rb')
+          @dummy = Dummy.new
+          @dummy.avatar = @file
+        end
+    
+        teardown { @file.close }
+    
+        context "and saved" do
+          setup do
+            AWS::S3::Base.stubs(:establish_connection!)
+            [:thumb, :original].each do |style|
+              AWS::S3::S3Object.expects(:store).with("avatars/#{style}/5k.png",
+                                                    anything,
+                                                    'testing',
+                                                    :content_type => 'image/png',
+                                                    :access => style == :thumb ? 'public-read' : 'private')
+            end
+            @dummy.save
+          end
+    
+          should "succeed" do
+            assert true
+          end
+        end
+      end
+    end
+  end
+
   unless ENV["S3_TEST_BUCKET"].blank?
     context "Using S3 for real, an attachment with S3 storage" do
       setup do