Make PaperTrail threadsafe.

README.md

@@ -18,6 +18,7 @@ PaperTrail lets you track changes to your models' data.  It's good for auditing
 * No configuration necessary.
 * Stores everything in a single database table (generates migration for you).
 * Thoroughly tested.
+* Threadsafe.
 
 
 ## Rails Version
@@ -206,7 +207,7 @@ And on again like this:
 
 ## Testing
 
-PaperTrail has a thorough suite of tests.  Thanks to [Zachery Hostens](http://github.com/zacheryph) for making them able to run standalone, i.e. without needing PaperTrail to be sitting in a Rails app.
+PaperTrail has a thorough suite of tests.
 
 
 ## Articles
@@ -225,6 +226,8 @@ Many thanks to:
 
 * [Zachery Hostens](http://github.com/zacheryph)
 * [Jeremy Weiskotten](http://github.com/jeremyw)
+* [Phan Le](http://github.com/revo)
+* [jdrucza](http://github.com/jdrucza)
 
 
 ## Inspirations

lib/paper_trail.rb

@@ -3,26 +3,29 @@ require 'paper_trail/has_paper_trail'
 require 'paper_trail/version'
 
 module PaperTrail
-  @@whodunnit = nil
 
   def self.included(base)
     base.before_filter :set_whodunnit
   end
 
   def self.whodunnit
-    @@whodunnit.respond_to?(:call) ? @@whodunnit.call : @@whodunnit
+    Thread.current[:whodunnit]
   end
 
+  # Sets who is responsible for any changes that occur.
+  # You would normally use this in a migration or on the console,
+  # when working with models directly.  In a controller it is set
+  # automatically to the `current_user`.
   def self.whodunnit=(value)
-    @@whodunnit = value
+    Thread.current[:whodunnit] = value
   end
 
-  private
+  protected
 
+  # Sets who is responsible for any changes that occur: the controller's
+  # `current_user`.
   def set_whodunnit
-    @@whodunnit = lambda {
-      self.send :current_user rescue nil
-    }
+    Thread.current[:whodunnit] = self.send :current_user rescue nil
   end
 end
 

test/thread_safe_test.rb

@@ -1,34 +1,32 @@
-require File.dirname(__FILE__) + '/test_helper.rb'
+require 'test_helper'
 
 class TestController < ActionController::Base
-  
   def current_user
-    @current_user ||= ActiveSupport::SecureRandom.hex(32)
+    Thread.current.object_id
   end
-
 end
 
 class ThreadSafeTest < Test::Unit::TestCase
-  
-  should "is thread safe when dealing with audit logging" do
+  should "be thread safe" do
     blocked = true
-    
-    blocked_thread = Thread.new do 
+
+    slow_thread = Thread.new do
       controller = TestController.new
-      controller.send(:set_whodunnit)
+      controller.send :set_whodunnit
       begin
-        puts "sleep for .001 sec"
-        sleep(0.001)
+        sleep 0.001
       end while blocked
       PaperTrail.whodunnit
     end
 
-    fast_running_thread = Thread.new do 
+    fast_thread = Thread.new do
       controller = TestController.new
-      controller.send(:set_whodunnit)
+      controller.send :set_whodunnit
+      who = PaperTrail.whodunnit
       blocked = false
-      PaperTrail.whodunnit
+      who
     end
-    assert_not_equal blocked_thread.value, fast_running_thread.value
+
+    assert_not_equal slow_thread.value, fast_thread.value
   end
-end
+end