Clean Paper Trail Versions

lib/paper_trail.rb

@@ -1,3 +1,4 @@
+require 'paper_trail/cleaner'
 require 'paper_trail/config'
 require 'paper_trail/controller'
 require 'paper_trail/has_paper_trail'
@@ -9,6 +10,7 @@
 # PaperTrail's module methods can be called in both models and controllers.
 module PaperTrail
 
+  extend PaperTrail::Cleaner
   # Switches PaperTrail on or off.
   def self.enabled=(value)
     PaperTrail.config.enabled = value

lib/paper_trail/cleaner.rb

@@ -0,0 +1,55 @@
+module PaperTrail
+  module Cleaner
+    def gather_all_versions
+      Version.all.group_by(&:item_id)
+    end
+
+    def get_all_keys
+      @versions.keys
+    end
+
+    def grouping_for_key(key)
+      @versions[key].group_by(&:grouping_by_date)
+    end
+
+    def sanitize(group)
+      group = keep_versions(group)
+      if group.size > 0
+        group.each do |member| 
+          member.destroy
+        end
+      end
+    end
+
+    def keep_versions(group)
+      @keeping_versions.times do
+        group.pop
+      end
+      group
+    end
+
+    def analyze_grouping(grouping)
+      grouping.each_value do |group|
+        sanitize(group)
+      end
+    end
+
+    def acquire_version_info
+      @versions = gather_all_versions
+      @keys = get_all_keys
+    end
+
+    def examine_and_clean_versions
+      @keys.each do |key|
+        grouping = grouping_for_key(key)
+        analyze_grouping(grouping)
+      end
+    end 
+
+    def clean_paper_trail_versions(keeping = 1)
+      @keeping_versions = keeping
+      acquire_version_info
+      examine_and_clean_versions
+    end
+  end
+end

lib/paper_trail/version.rb

@@ -139,6 +139,10 @@ def index
     sibling_versions.select(id_column).order("#{id_column} ASC").map(&id_column).index(self.send(id_column))
   end
 
+  def grouping_by_date
+    created_at.to_date.to_s(:db)
+  end
+
   private
 
   # In Rails 3.1+, calling reify on a previous version confuses the

test/unit/cleaner_test.rb

@@ -0,0 +1,61 @@
+require 'test_helper'
+
+class PaperTrailCleanerTest < ActiveSupport::TestCase
+
+  test 'Baseline' do
+    @animal = Animal.create :name => 'Animal'
+    @animal.update_attributes :name => 'Animal from the Muppets'
+    @animal.update_attributes :name => 'Animal Muppet'
+
+    @dog = Dog.create :name => 'Snoopy'
+    @dog.update_attributes :name => 'Scooby'
+    @dog.update_attributes :name => 'Scooby Doo'
+
+    @cat = Cat.create :name => 'Garfield'
+    @cat.update_attributes :name => 'Garfield (I hate Mondays)'
+    @cat.update_attributes :name => 'Garfield The Cat'
+    assert_equal 9, Version.count
+  end
+
+  test 'cleaner removes extra versions' do
+    @animal = Animal.create :name => 'Animal'
+    @animal.update_attributes :name => 'Animal from the Muppets'
+    @animal.update_attributes :name => 'Animal Muppet'
+    PaperTrail.clean_paper_trail_versions
+    assert_equal 1, Version.all.count
+  end
+
+  test 'cleaner removes versions' do
+    @animal = Animal.create :name => 'Animal'
+    @animal.update_attributes :name => 'Animal from the Muppets'
+    @animal.update_attributes :name => 'Animal Muppet'
+
+    @dog = Dog.create :name => 'Snoopy'
+    @dog.update_attributes :name => 'Scooby'
+    @dog.update_attributes :name => 'Scooby Doo'
+
+    @cat = Cat.create :name => 'Garfield'
+    @cat.update_attributes :name => 'Garfield (I hate Mondays)'
+    @cat.update_attributes :name => 'Garfield The Cat'
+    PaperTrail.clean_paper_trail_versions
+    assert_equal 3, Version.all.count
+  end
+
+  test 'cleaner keeps the correct (last) version' do
+    @animal = Animal.create :name => 'Animal'
+    @animal.update_attributes :name => 'Animal from the Muppets'
+    @animal.update_attributes :name => 'Animal Muppet'
+    PaperTrail.clean_paper_trail_versions
+    assert_equal 1, Version.all.count
+    assert_equal "Animal Muppet", @animal.name
+  end
+
+  test 'cleaner accepts variable arguments' do
+    @animal = Animal.create :name => 'Animal'
+    @animal.update_attributes :name => 'Animal from the Muppets'
+    @animal.update_attributes :name => 'Animal Muppet'
+    PaperTrail.clean_paper_trail_versions(2)
+    assert_equal 2, Version.all.count
+    assert_equal "Animal Muppet", @animal.name
+  end
+end