Allow custom expires-at when building an authenticated-url

lib/carrierwave/storage/fog.rb

@@ -190,7 +190,7 @@ def authenticated_url(options = {})
             # avoid a get by using local references
             local_directory = connection.directories.new(:key => @uploader.fog_directory)
             local_file = local_directory.files.new(:key => path)
-            expire_at = ::Fog::Time.now + @uploader.fog_authenticated_url_expiration
+            expire_at = options[:expire_at] || ::Fog::Time.now + @uploader.fog_authenticated_url_expiration
             case @uploader.fog_credentials[:provider]
               when 'AWS', 'Google'
                 # Older versions of fog-google do not support options as a parameter

spec/storage/fog_helper.rb

@@ -443,6 +443,17 @@ class FogSpec#{fog_credentials[:provider]}Uploader < CarrierWave::Uploader::Base
             end
           end
 
+          it "should have an custom authenticated_url" do
+            if ['AWS', 'Rackspace', 'Google', 'OpenStack', 'AzureRM'].include?(@provider)
+              timestamp = ::Fog::Time.now + 999
+              if @provider == "AWS"
+                expect(@fog_file.authenticated_url({expire_at: timestamp })).to include("Expires=999&")
+              elsif @provider == "Google"
+                expect(@fog_file.authenticated_url({expire_at: timestamp })).to include("Expires=#{timestamp.to_i}")
+              end
+            end
+          end
+
           it 'should generate correct filename' do
             expect(@fog_file.filename).to eq('private.txt')
           end