Added :rails_env as a path/url interpolation variable. Useful for networked storage.

lib/paperclip/attachment.rb

@@ -161,6 +161,7 @@ module Paperclip
     def self.interpolations
       @interpolations ||= {
         :rails_root   => lambda{|attachment,style| RAILS_ROOT },
+        :rails_env    => lambda{|attachment,style| RAILS_ENV },
         :class        => lambda do |attachment,style|
                            attachment.instance.class.name.underscore.pluralize
                          end,

test/attachment_test.rb

@@ -86,6 +86,26 @@ class AttachmentTest < Test::Unit::TestCase
     end
   end
 
+  context "An attachment with a :rails_env interpolation" do
+    setup do
+      @rails_env = "blah"
+      @id = 1024
+      rebuild_model :path => ":rails_env/:id.png"
+      @dummy = Dummy.new
+      @dummy.stubs(:id).returns(@id)
+      @file = File.new(File.join(File.dirname(__FILE__),
+                                 "fixtures",
+                                 "5k.png"))
+      @dummy.avatar = @file
+    end
+
+    should "return the proper path" do
+      temporary_rails_env(@rails_env) {
+        assert_equal "#{@rails_env}/#{@id}.png", @dummy.avatar.path
+      }
+    end
+  end
+
   context "Assigning an attachment" do
     setup do
       rebuild_model

test/helper.rb

@@ -5,6 +5,7 @@ require 'mocha'
 require 'tempfile'
 
 require 'active_record'
+require 'active_support'
 begin
   require 'ruby-debug'
 rescue LoadError
@@ -43,3 +44,14 @@ def rebuild_model options = {}
     has_attached_file :avatar, options
   end
 end
+
+def temporary_rails_env(new_env)
+  old_env = defined?(RAILS_ENV) ? RAILS_ENV : nil
+  silence_warnings do
+    Object.const_set("RAILS_ENV", new_env)
+  end
+  yield
+  silence_warnings do
+    Object.const_set("RAILS_ENV", old_env)
+  end
+end