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).
Mongoid History supports the following dependency versions:
- Ruby 2.3+
- Mongoid 3.1+
- Recent JRuby versions
Earlier Ruby versions may work but are untested.
gem 'mongoid-history'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
endMongoid::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_trackerclass 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
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
endYou 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
endInclude 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" }], ... }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
endIt will now track only _id (Mandatory), title and content attributes for pages relation.
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) #=> falseclass Book
...
track_history :on => [:pages]
end
Book.tracked_relation?(:pages) #=> true
Book.tracked_embeds_many #=> ["pages"]
Book.tracked_embeds_many?(:pages) #=> trueDefault 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
endThis will skip the page documents with removed_at set to a non-blank value from nested tracking
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
endIn 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})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
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'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 }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
endExample 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
endFor more examples, check out spec/integration/integration_spec.rb.
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
endNote 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.
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.
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.
You're encouraged to contribute to Mongoid History. See CONTRIBUTING.md for details.
Copyright (c) 2011-2020 Aaron Qian and Contributors.
MIT License. See LICENSE.txt for further details.
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