Change the default :url and :path to avoid conflicts. Closes #727.

The new default :path and :include include the name of the model and
also nests the model ID under a series of subdirectories, improving
filesystem access speed when more than 1024 models have saved
attachments.

The easiest way to upgrade is to add an explicit :url and :path to your
has_attached_file calls:

    has_attached_file :avatar,
      :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
      :url => "/system/:attachment/:id/:style/:filename"

NEWS

+* API CHANGE: The default :url and :path have changed. The new scheme avoids
+  filesystem conflicts and scales to handle larger numbers of uploads.
+
+  The easiest way to upgrade is to add an explicit :url and :path to your
+  has_attached_file calls:
+  
+      has_attached_file :avatar,
+        :path => ":rails_root/public/system/:attachment/:id/:style/:filename",
+        :url => "/system/:attachment/:id/:style/:filename"
+
 New in 2.7.0:
 
 * Bug fix: Checking the existence of a file on S3 handles all AWS errors.

features/basic_integration.feature

@@ -19,8 +19,8 @@ Feature: Rails integration
     And I attach the file "test/fixtures/5k.png" to "Attachment"
     And I press "Submit"
     Then I should see "Name: something"
-    And I should see an image with a path of "/system/attachments/1/original/5k.png"
-    And the file at "/system/attachments/1/original/5k.png" should be the same as "test/fixtures/5k.png"
+    And I should see an image with a path of "/system/users/attachments/000/000/001/original/5k.png"
+    And the file at "/system/users/attachments/000/000/001/original/5k.png" should be the same as "test/fixtures/5k.png"
 
   Scenario: S3 Integration test
     Given I add this snippet to the User model:

lib/paperclip/attachment.rb

@@ -25,7 +25,7 @@ module Paperclip
         :source_file_options   => {},
         :storage               => :filesystem,
         :styles                => {},
-        :url                   => "/system/:attachment/:id/:style/:filename",
+        :url                   => "/system/:class/:attachment/:id_partition/:style/:filename",
         :url_generator         => Paperclip::UrlGenerator,
         :use_default_time_zone => true,
         :use_timestamp         => true,

test/attachment_test.rb

@@ -103,6 +103,15 @@ class AttachmentTest < Test::Unit::TestCase
     assert_equal "#{Rails.root}/public/fake_models/1234/fake", @attachment.path
   end
 
+  should "default to a path that scales" do
+    avatar_attachment = attachment
+    model = avatar_attachment.instance
+    model.id = 1234
+    model.avatar_file_name = "fake.jpg"
+    expected_path = "#{Rails.root}/public/system/fake_models/avatars/000/001/234/original/fake.jpg"
+    assert_equal expected_path, avatar_attachment.path
+  end
+
   context "Attachment default_options" do
     setup do
       rebuild_model

test/helper.rb

@@ -121,7 +121,7 @@ class FakeModel
 
 end
 
-def attachment options
+def attachment(options={})
   Paperclip::Attachment.new(:avatar, FakeModel.new, options)
 end
 

test/integration_test.rb

@@ -90,7 +90,7 @@ class IntegrationTest < Test::Unit::TestCase
 
   context "Attachment" do
     setup do
-      @thumb_path = "./test/../public/system/avatars/1/thumb/5k.png"
+      @thumb_path = "./test/../public/system/dummies/avatars/000/000/001/thumb/5k.png"
       File.delete(@thumb_path) if File.exists?(@thumb_path)
       rebuild_model :styles => { :thumb => "50x50#" }
       @dummy = Dummy.new
@@ -119,8 +119,8 @@ class IntegrationTest < Test::Unit::TestCase
 
   context "Attachment with no generated thumbnails" do
     setup do
-      @thumb_small_path = "./test/../public/system/avatars/1/thumb_small/5k.png"
-      @thumb_large_path = "./test/../public/system/avatars/1/thumb_large/5k.png"
+      @thumb_small_path = "./test/../public/system/dummies/avatars/000/000/001/thumb_small/5k.png"
+      @thumb_large_path = "./test/../public/system/dummies/avatars/000/000/001/thumb_large/5k.png"
       File.delete(@thumb_small_path) if File.exists?(@thumb_small_path)
       File.delete(@thumb_large_path) if File.exists?(@thumb_large_path)
       rebuild_model :styles => { :thumb_small => "50x50#", :thumb_large => "60x60#" }

test/paperclip_test.rb

@@ -87,12 +87,13 @@ class PaperclipTest < Test::Unit::TestCase
     end
 
     should "generate warning if attachment is redefined with the same url string" do
-      Paperclip.expects(:log).with("Duplicate URL for blah with /system/:attachment/:id/:style/:filename. This will clash with attachment defined in Dummy class")
+      expected_log_msg = "Duplicate URL for blah with /system/:id/:style/:filename. This will clash with attachment defined in Dummy class"
+      Paperclip.expects(:log).with(expected_log_msg)
       Dummy.class_eval do
-        has_attached_file :blah
+        has_attached_file :blah, :url => '/system/:id/:style/:filename'
       end
       Dummy2.class_eval do
-        has_attached_file :blah
+        has_attached_file :blah, :url => '/system/:id/:style/:filename'
       end
     end