Awesome
Mongoid History
Mongoid History tracks historical changes for any document, including embedded ones. It achieves this by storing all history tracks in a single collection that you define. Embedded documents are referenced by storing an association path, which is an array of document_name and document_id fields starting from the top most parent document and down to the embedded document that should track history.
This gem also implements multi-user undo, which allows users to undo any history change in any order. Undoing a document also creates a new history track. This is great for auditing and preventing vandalism, but is probably not suitable for use cases such as a wiki (but we won't stop you either).
Version Support
Mongoid History supports the following dependency versions:
- Ruby 2.3+
- Mongoid 3.1+
- Recent JRuby versions
Earlier Ruby versions may work but are untested.
Install
gem 'mongoid-history'
Usage
Create a history tracker
Create a new class to track histories. All histories are stored in this tracker. The name of the class can be anything you like. The only requirement is that it includes Mongoid::History::Tracker
# app/models/history_tracker.rb
class HistoryTracker
include Mongoid::History::Tracker
end
Set default tracker class name (optional)
Mongoid::History will use the first loaded class to include Mongoid::History::Tracker as the default history tracker. If you are using multiple Tracker classes, you should set a global default in a Rails initializer:
# config/initializers/mongoid_history.rb
# initializer for mongoid-history
# assuming HistoryTracker is your tracker class
Mongoid::History.tracker_class_name = :history_tracker
Create trackable classes and objects
class Post
include Mongoid::Document
include Mongoid::Timestamps
# history tracking all Post documents
# note: tracking will not work until #track_history is invoked
include Mongoid::History::Trackable
field :title
field :body
field :rating
embeds_many :comments
# telling Mongoid::History how you want to track changes
# dynamic fields will be tracked automatically (for MongoId 4.0+ you should include Mongoid::Attributes::Dynamic to your model)
track_history :on => [:title, :body], # track title and body fields only, default is :all
:modifier_field => :modifier, # adds "belongs_to :modifier" to track who made the change, default is :modifier, set to nil to not create modifier_field
:modifier_field_inverse_of => :nil, # adds an ":inverse_of" option to the "belongs_to :modifier" relation, default is not set
:modifier_field_optional => true, # marks the modifier relationship as optional (requires Mongoid 6 or higher)
:version_field => :version, # adds "field :version, :type => Integer" to track current version, default is :version
:track_create => true, # track document creation, default is true
:track_update => true, # track document updates, default is true
:track_destroy => true, # track document destruction, default is true
:track_blank_changes => false # track changes from blank? to blank?, default is false
end
class Comment
include Mongoid::Document
include Mongoid::Timestamps
# declare that we want to track comments
include Mongoid::History::Trackable
field :title
field :body
embedded_in :post, :inverse_of => :comments
# track title and body for all comments, scope it to post (the parent)
# also track creation and destruction
track_history :on => [:title, :body], :scope => :post, :track_create => true, :track_destroy => true
# For embedded polymorphic relations, specify an array of model names or its polymorphic name
# e.g. :scope => [:post, :image, :video]
# :scope => :commentable
end
# the modifier class
class User
include Mongoid::Document
include Mongoid::Timestamps
field :name
end
user = User.create(:name => "Aaron")
post = Post.create(:title => "Test", :body => "Post", :modifier => user)
comment = post.comments.create(:title => "test", :body => "comment", :modifier => user)
comment.history_tracks.count # should be 1
comment.update_attributes(:title => "Test 2")
comment.history_tracks.count # should be 2
track = comment.history_tracks.last
track.undo! user # comment title should be "Test"
track.redo! user # comment title should be "Test 2"
# undo comment to version 1 without save
comment.undo nil, from: 1, to: comment.version
# undo last change
comment.undo! user
# undo versions 1 - 4
comment.undo! user, :from => 4, :to => 1
# undo last 3 versions
comment.undo! user, :last => 3
# redo versions 1 - 4
comment.redo! user, :from => 1, :to => 4
# redo last 3 versions
comment.redo! user, :last => 3
# redo version 1
comment.redo! user, 1
# delete post
post.destroy
# undelete post
post.undo! user
# disable tracking for comments within a block
Comment.disable_tracking do
comment.update_attributes(:title => "Test 3")
end
# disable tracking for comments by default
Comment.disable_tracking!
# enable tracking for comments within a block
Comment.enable_tracking do
comment.update_attributes(:title => "Test 3")
end
# renable tracking for comments by default
Comment.enable_tracking!
# globally disable all history tracking within a block
Mongoid::History.disable do
comment.update_attributes(:title => "Test 3")
user.update_attributes(:name => "Eddie Van Halen")
end
# globally disable all history tracking by default
Mongoid::History.disable!
# globally enable all history tracking within a block
Mongoid::History.enable do
comment.update_attributes(:title => "Test 3")
user.update_attributes(:name => "Eddie Van Halen")
end
# globally renable all history tracking by default
Mongoid::History.enable!
You may want to track changes on all fields.
class Post
include Mongoid::Document
include Mongoid::History::Trackable
field :title
field :body
field :rating
track_history :on => [:fields] # all fields will be tracked
end
You can also track changes on all embedded relations.
class Post
include Mongoid::Document
include Mongoid::History::Trackable
embeds_many :comments
embeds_one :content
track_history :on => [:embedded_relations] # all embedded relations will be tracked
end
Include embedded objects attributes in parent audit
Modify above Post and Comment classes as below:
class Post
include Mongoid::Document
include Mongoid::Timestamps
include Mongoid::History::Trackable
field :title
field :body
field :rating
embeds_many :comments
track_history :on => [:title, :body, :comments],
:modifier_field => :modifier,
:modifier_field_inverse_of => :nil,
:version_field => :version,
:track_create => true, # track create on Post
:track_update => true,
:track_destroy => false
end
class Comment
include Mongoid::Document
include Mongoid::Timestamps
field :title
field :body
embedded_in :post, :inverse_of => :comments
end
user = User.create(:name => "Aaron")
post = Post.create(:title => "Test", :body => "Post", :modifier => user)
comment = post.comments.build(:title => "test", :body => "comment", :modifier => user)
post.save
post.history_tracks.count # should be 1
comment.respond_to?(:history_tracks) # should be false
track = post.history_tracks.first
track.original # {}
track.modified # { "title" => "Test", "body" => "Post", "comments" => [{ "_id" => "575fa9e667d827e5ed00000d", "title" => "test", "body" => "comment" }], ... }
Whitelist the tracked attributes of embedded relations
If you don't want to track all the attributes of embedded relations in parent audit history, you can whitelist the attributes as below:
class Book
include Mongoid::Document
...
embeds_many :pages
track_history :on => { :pages => [:title, :content] }
end
class Page
include Mongoid::Document
...
field :number
field :title
field :subtitle
field :content
embedded_in :book
end
It will now track only _id (Mandatory), title and content attributes for pages relation.
Track all blank changes
Normally changes where both the original and modified values respond with true to blank? (for example nil to false) aren't tracked. However, there may be cases where it's important to track such changes, for example when a field isn't present (so appears to be nil) then is set to false. To track such changes, set the track_blank_changes option to true (it defaults to false) when turning on history tracking:
class Book
include Mongoid::Document
...
field :summary
track_history # Use default of false for track_blank_changes
end
# summary change not tracked if summary hasn't been set (or has been set to something that responds true to blank?)
Book.find(id).update_attributes(:summary => '')
class Chapter
include Mongoid::Document
...
field :title
track_history :track_blank_changes => true
end
# title change tracked even if title hasn't been set
Chapter.find(id).update_attributes(:title => '')
Retrieving the list of tracked static and dynamic fields
class Book
...
field :title
field :author
field :price
track_history :on => [:title, :price]
end
Book.tracked_fields #=> ["title", "price"]
Book.tracked_field?(:title) #=> true
Book.tracked_field?(:author) #=> false
Retrieving the list of tracked relations
class Book
...
track_history :on => [:pages]
end
Book.tracked_relation?(:pages) #=> true
Book.tracked_embeds_many #=> ["pages"]
Book.tracked_embeds_many?(:pages) #=> true
Skip soft-deleted embedded objects with nested tracking
Default paranoia field is deleted_at. You can use custom field for each class as below:
class Book
include Mongoid::Document
include Mongoid::History::Trackable
embeds_many :pages
track_history on: :pages
end
class Page
include Mongoid::Document
include Mongoid::History::Trackable
...
embedded_in :book
history_settings paranoia_field: :removed_at
end
This will skip the page documents with removed_at set to a non-blank value from nested tracking
Formatting fields
You can opt to use a proc or string interpolation to alter attributes being stored on a history record.
class Post
include Mongoid::Document
include Mongoid::History::Trackable
field :title
track_history on: :title,
format: { title: ->(t){ t[0..3] } }
This also works for fields on an embedded relations.
class Book
include Mongoid::Document
include Mongoid::History::Trackable
embeds_many :pages
track_history on: :pages,
format: { pages: { number: 'pg. %d' } }
end
class Page
include Mongoid::Document
include Mongoid::History::Trackable
field :number, type: Integer
embedded_in :book
end
Displaying history trackers as an audit trail
In your Controller:
# Fetch history trackers
@trackers = HistoryTracker.limit(25)
# get change set for the first tracker
@changes = @trackers.first.tracked_changes
#=> {field: {to: val1, from: val2}}
# get edit set for the first tracker
@edits = @trackers.first.tracked_edits
#=> { add: {field: val},
# remove: {field: val},
# modify: { to: val1, from: val2 },
# array: { add: [val2], remove: [val1] } }
In your View, you might do something like (example in HAML format):
%ul.changes
- (@edits[:add]||[]).each do |k,v|
%li.remove Added field #{k} value #{v}
- (@edits[:modify]||[]).each do |k,v|
%li.modify Changed field #{k} from #{v[:from]} to #{v[:to]}
- (@edits[:array]||[]).each do |k,v|
%li.modify
- if v[:remove].nil?
Changed field #{k} by adding #{v[:add]}
- elsif v[:add].nil?
Changed field #{k} by removing #{v[:remove]}
- else
Changed field #{k} by adding #{v[:add]} and removing #{v[:remove]}
- (@edits[:remove]||[]).each do |k,v|
%li.remove Removed field #{k} (was previously #{v})
Adding Userstamp on History Trackers
To track the User in the application who created the HistoryTracker, add the
Mongoid::Userstamp gem to your HistoryTracker class.
This will add a field called created_by and an accessor creator to the model (you can rename these via gem config).
class MyHistoryTracker
include Mongoid::History::Tracker
include Mongoid::Userstamp
end
Setting Modifier Class Name
If your app will track history changes to a user, Mongoid History looks for these modifiers in the User class by default. If you have named your 'user' accounts differently, you will need to add that to your Mongoid History config:
The following examples set the modifier class name using a Rails initializer:
If your app uses a class Author:
# config/initializers/mongoid-history.rb
# initializer for mongoid-history
Mongoid::History.modifier_class_name = 'Author'
Or perhaps you are namespacing to a module:
Mongoid::History.modifier_class_name = 'CMS::Author'
Conditional :if and :unless options
The track_history method supports :if and :unless options which will skip generating
the history tracker unless they are satisfied. These options can take either a method
Symbol or a Proc. They behave identical to how :if and :unless behave in Rails model callbacks.
track_history on: [:ip],
if: :should_i_track_history?,
unless: ->(obj){ obj.method_to_skip_history }
Using an alternate changes method
Sometimes you may wish to provide an alternate method for determining which changes should be tracked. For example, if you are using embedded documents and nested attributes, you may wish to write your own changes method that includes changes from the embedded documents.
Mongoid::History provides an option named :changes_method which allows you to do this. It defaults to :changes, which is the standard changes method.
Note: Specify additional fields that are provided with a custom changes_method with the :on option.. To specify current fields and additional fields, use fields.keys + [:custom]
Example:
class Foo
include Mongoid::Document
include Mongoid::History::Trackable
attr_accessor :ip
track_history on: [:ip], changes_method: :my_changes
def my_changes
unless ip.nil?
changes.merge(ip: [nil, ip])
else
changes
end
end
end
Example with embedded & nested attributes:
class Foo
include Mongoid::Document
include Mongoid::Timestamps
include Mongoid::History::Trackable
field :bar
embeds_one :baz
accepts_nested_attributes_for :baz
# use changes_with_baz to include baz's changes in this document's
# history.
track_history on: fields.keys + [:baz], changes_method: :changes_with_baz
def changes_with_baz
if baz.changed?
changes.merge(baz: summarized_changes(baz))
else
changes
end
end
private
# This method takes the changes from an embedded doc and formats them
# in a summarized way, similar to how the embedded doc appears in the
# parent document's attributes
def summarized_changes obj
obj.changes.keys.map do |field|
next unless obj.respond_to?("#{field}_change")
[ { field => obj.send("#{field}_change")[0] },
{ field => obj.send("#{field}_change")[1] } ]
end.compact.transpose.map do |fields|
fields.inject({}) {|map,f| map.merge(f)}
end
end
end
class Baz
include Mongoid::Document
include Mongoid::Timestamps
embedded_in :foo
field :value
end
For more examples, check out spec/integration/integration_spec.rb.
Multiple Trackers
You can have different trackers for different classes like so.
class First
include Mongoid::Document
include Mongoid::History::Trackable
field :text, type: String
track_history on: [:text],
tracker_class_name: :first_history_tracker
end
class Second
include Mongoid::Document
include Mongoid::History::Trackable
field :text, type: String
track_history on: [:text],
tracker_class_name: :second_history_tracker
end
class FirstHistoryTracker
include Mongoid::History::Tracker
end
class SecondHistoryTracker
include Mongoid::History::Tracker
end
Note that if you are using a tracker for an embedded object that is different from the parent's tracker, redos and undos will not work. You have to use the same tracker for these to work across embedded relationships.
If you are using multiple trackers and the tracker_class_name parameter is
not specified, Mongoid::History will use the default tracker configured in the
initializer file or whatever the first tracker was loaded.
Dependent Restrict Associations
When dependent: :restrict is used on an association, a call to destroy on
the model will raise Mongoid::Errors::DeleteRestriction when the dependency
is violated. Just be aware that this gem will create a history track document
before the destroy call and then remove if an error is raised. This applies
to all persistence calls: create, update and destroy.
See spec/integration/validation_failure_spec.rb for examples.
Thread Safety
Mongoid::History stores the tracking enable/disable flag in Thread.current.
If the RequestStore gem is installed, Mongoid::History
will automatically store variables in the RequestStore.store instead. RequestStore is recommended
for threaded web servers like Thin or Puma.
Contributing
You're encouraged to contribute to Mongoid History. See CONTRIBUTING.md for details.
Copyright
Copyright (c) 2011-2024 Aaron Qian and Contributors.
MIT License. See LICENSE.txt for further details.