Back fetching modifier from controller

Author: melnikaite

Diff for: .rubocop_todo.yml

@@ -32,7 +32,7 @@ Metrics/MethodLength:
 # Offense count: 2
 # Configuration parameters: CountComments.
 Metrics/ModuleLength:
-  Max: 168
+  Max: 174
 
 # Offense count: 4
 Metrics/PerceivedComplexity:
@@ -42,6 +42,7 @@ Metrics/PerceivedComplexity:
 Style/Documentation:
   Exclude:
     - 'lib/mongoid/history.rb'
+    - 'lib/mongoid/history/hooks.rb'
     - 'lib/mongoid/history/trackable.rb'
     - 'lib/mongoid/history/tracker.rb'
     - 'lib/mongoid/history/version.rb'

Diff for: CHANGELOG.md

@@ -1,6 +1,7 @@
 0.5.1 (Next)
 ------------
 
+* [#149](https://github.com/aq1018/mongoid-history/pull/149): Back fetching modifier from controller - [@melnikaite](https://github.com/melnikaite).
 * Your contribution here.
 
 0.5.0 (2015/09/18)

Diff for: README.md

@@ -47,6 +47,40 @@ The following example sets the tracker class name using a Rails initializer.
 Mongoid::History.tracker_class_name = :history_tracker
 ```
 
+**Set controller**
+
+Add hooks to ApplicationController to fetch modifier automatically.
+
+```ruby
+# app/controllers/application_controller.rb
+class ApplicationController
+  include Mongoid::History::Hooks
+end
+```
+
+**Set `#current_user` method name**
+
+You can set the name of the method that returns currently logged in user if you don't want to set `modifier` explicitly on every update.
+
+The following example sets the `current_user_method` using a Rails initializer
+
+```ruby
+# config/initializers/mongoid-history.rb
+# initializer for mongoid-history
+# assuming you're using devise/authlogic
+Mongoid::History.current_user_method = :current_user
+```
+
+When `current_user_method` is set, mongoid-history will invoke this method on each update and set its result as the instance modifier.
+
+```ruby
+# assume that current_user return #<User _id: 1>
+post = Post.first
+post.update_attributes(:title => 'New title')
+
+post.history_tracks.last.modifier #=> #<User _id: 1>
+```
+
 **Create trackable classes and objects**
 
 ```ruby

Diff for: lib/mongoid/history.rb

@@ -3,6 +3,7 @@
 require 'mongoid/history/version'
 require 'mongoid/history/tracker'
 require 'mongoid/history/trackable'
+require 'mongoid/history/hooks'
 
 module Mongoid
   module History

Diff for: lib/mongoid/history/hooks.rb

@@ -0,0 +1,13 @@
+module Mongoid
+  module History
+    module Hooks
+      extend ActiveSupport::Concern
+
+      included do
+        before_action do |controller|
+          Thread.current[:mongoid_history_controller] = controller
+        end
+      end
+    end
+  end
+end

Diff for: lib/mongoid/history/trackable.rb

@@ -238,6 +238,13 @@ def history_tracker_attributes(action)
             modifier: send(history_trackable_options[:modifier_field])
           }
 
+          unless @history_tracker_attributes[:modifier]
+            controller = Thread.current[:mongoid_history_controller]
+            if controller && controller.respond_to?(Mongoid::History.current_user_method, true)
+              @history_tracker_attributes[:modifier] = controller.send(Mongoid::History.current_user_method)
+            end
+          end
+
           original, modified = transform_changes(modified_attributes_for_action(action))
 
           @history_tracker_attributes[:original] = original

Diff for: lib/mongoid/history/tracker.rb

@@ -14,7 +14,12 @@ module Tracker
         field :version,                 type: Integer
         field :action,                  type: String
         field :scope,                   type: String
-        belongs_to :modifier, class_name: Mongoid::History.modifier_class_name
+        if respond_to? :t_belongs_to
+          # Tenacity support https://github.com/jwood/tenacity
+          t_belongs_to :modifier, class_name: Mongoid::History.modifier_class_name
+        else
+          belongs_to :modifier, class_name: Mongoid::History.modifier_class_name
+        end
 
         index(scope: 1)
         index(association_chain: 1)

Diff for: spec/integration/integration_spec.rb

@@ -71,6 +71,9 @@ class Tag
     class Foo < Comment
     end
 
+    class Controller
+    end
+
     @persisted_history_options = Mongoid::History.trackable_class_options
   end
 
@@ -536,6 +539,14 @@ class Foo < Comment
         expect(tag_foo.history_tracks.last.association_chain.last['name']).to eq('tags')
         expect { tag_foo.history_tracks.last.trackable }.not_to raise_error
       end
+
+      it 'should save modifier' do
+        Thread.current[:mongoid_history_controller] = Controller.new
+        allow_any_instance_of(Controller).to receive(:current_user).and_return(user)
+        expect(Thread.current[:mongoid_history_controller].current_user).to eq user
+        expect(tag_foo.history_tracks.last.modifier).to eq user
+        expect(tag_bar.history_tracks.last.modifier).to eq user
+      end
     end
 
     describe 'non-embedded' do

Diff for: spec/support/mongoid_history.rb

@@ -9,5 +9,6 @@ class Tracker
   config.after :each do
     Mongoid::History.tracker_class_name = nil
     Mongoid::History.trackable_class_options = nil
+    Thread.current[:mongoid_history_controller] = nil
   end
 end