Fix Fog's slow `public_url` access

lib/paperclip/storage/fog.rb

@@ -51,6 +51,8 @@ module Paperclip
         end
       end
 
+      AWS_BUCKET_SUBDOMAIN_RESTRICTON_REGEX = /^(?:[a-z]|\d(?!\d{0,2}(?:\.\d{1,3}){3}$))(?:[a-z0-9]|\.(?![\.\-])|\-(?![\.])){1,61}[a-z0-9]$/
+
       def exists?(style = default_style)
         if original_filename
           !!directory.files.head(path(style))
@@ -126,7 +128,16 @@ module Paperclip
           host = (@options[:fog_host] =~ /%d/) ? @options[:fog_host] % (path(style).hash % 4) : @options[:fog_host]
           "#{host}/#{path(style)}"
         else
-          directory.files.new(:key => path(style)).public_url
+          if fog_credentials[:provider] == 'AWS'
+            if @options[:fog_directory].to_s =~ Fog::AWS_BUCKET_SUBDOMAIN_RESTRICTON_REGEX
+              "https://#{@options[:fog_directory]}.s3.amazonaws.com/#{path(style)}"
+            else
+              # directory is not a valid subdomain, so use path style for access
+              "https://s3.amazonaws.com/#{@options[:fog_directory]}/#{path(style)}"
+            end
+          else
+            directory.files.new(:key => path(style)).public_url
+          end
         end
       end
 

test/storage/fog_test.rb

@@ -186,6 +186,33 @@ class FogTest < Test::Unit::TestCase
         end
       end
 
+      context "with a valid bucket name for a subdomain" do
+        should "provide an url in subdomain style" do
+          assert_match /^https:\/\/papercliptests.s3.amazonaws.com\/avatars\/5k.png\?\d*$/, @dummy.avatar.url
+        end
+      end
+
+      context "with an invalid bucket name for a subdomain" do
+        setup do
+          rebuild_model(@options.merge(:fog_directory => "this_is_invalid"))
+          @dummy = Dummy.new
+          @dummy.avatar = @file
+          @dummy.save
+        end
+
+        should "not match the bucket-subdomain restrictions" do
+          invalid_subdomains = %w(this_is_invalid in iamareallylongbucketnameiamareallylongbucketnameiamareallylongbu invalid- inval..id inval-.id inval.-id -invalid 192.168.10.2)
+          invalid_subdomains.each do |name|
+            assert_no_match Paperclip::Storage::Fog::AWS_BUCKET_SUBDOMAIN_RESTRICTON_REGEX, name
+          end
+        end
+
+        should "provide an url in folder style" do
+          assert_match /^https:\/\/s3.amazonaws.com\/this_is_invalid\/avatars\/5k.png\?\d*$/, @dummy.avatar.url
+        end
+
+      end
+
     end
 
   end