version_fu
version_fu is a ActveRecord versioning plugin that takes advantage of the new dirty attribute checking available in Rails 2.1. Previous solutions like Rick Olson’s acts_as_versioned are no long compatible with Rails.
nbudin-version_fu is Nat Budin’s attempt to merge revo’s Gemified version with jmckible’s latest additions and fixes. Nat hopes to have these changes merged into mainline version_fu eventually so that it can be released as a gem.
Installation
gem install nbudin-version_fu
Installation in a Rails application
In your config/environment.rb, or in an initializer, add the line:
config.gem "nbudin-version_fu", :lib => "version_fu", :source => "http://gemcutter.org"
Then run:
sudo rake gems:install
Usage
Let’s say I have a pages table:
class Page < ActiveRecord::Base
# attributes: id, type, title, body, created_at, updated_at, creator_id, author_id
end
I want to track any changes made. First step will be to make a new page_versions table:
class CreatePageVersions < ActiveRecord::Migration
def self.up
create_table :page_versions do |t|
t.integer :page_id, :version, :author_id
t.string :title
t.text :body
t.
end
end
def self.down
drop_table :page_versions
end
end
In this case, the author_id column represents the last person to edit the page. We want to track this attribute with every version. However, the creator_id is the person who created the page. The will never change, so it’s not part of the versioned table.
Don’t forget to add a version column to your pages table. Have it default to 1 just to be safe (although the plugin should account for this):
class AddVersionToPages < ActiveRecord::Migration
def self.up
add_column :pages, :version, :integer, :default=>1
end
def self.down
remove_column :pages, :version
end
end
Of course if you’re adding this plugin to a table with existing data, you’ll probably want to instantiate some initial versions to start with.
Alright, so now that the database tables are in place, we can fire up version_fu. It’s quite simple:
class Page < ActiveRecord::Base
version_fu
end
Thats it.
Configuration
You can pass a few configuration options if need be. If you stick with the defaults above, you can skip all this.
class Page < ActiveRecord::Base
version_fu :class_name=>'Version', :foreign_key=>'page_id', :table_name=>'page_versions', :version_column=>'version'
end
-
:class_name - The name of the versioned class. It will be a submodule of the versioning class - e.g. Page::Version
-
:foreign_key - The column in the versioned table associated with the versioning class
-
:table_name - The name of the versioned table
-
:version_column - The name of the version column
Extensions
Now that you’ve got some versions, it would be nice to use ActiveRecord associations on it. For example, Page.first.versions.latest.author wouldn’t currently work because the Page::Version class doesn’t know about the author method. The version_fu call does all you to pass a block which is executed by the versioned class. There is just one gotcha for associations:
class Page < ActiveRecord::Base
version_fu do
belongs_to :author, :class_name=>'::Author'
end
end
Don’t forget the class name, or you’ll get a warning
When to Version
By default a new version will be saved whenever a versioned column is changed. However, you can control this at a more fine grained level. Just override the create_new_version? method. For example, let’s say you only want to save a new version if both the page title and body changed. Taking advantage of the dirty attribute methods, you could do something like this:
class Page < ActiveRecord::Base
version_fu do
belongs_to :author, :class_name=>'::Author'
end
def create_new_version?
title_changed? && body_changed?
end
end
Author
-
version_fu was created by Jordan McKible jordan.mckible.com
-
Available on GitHub at github.com/jmckible/version_fu/tree/master
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Hosted on Gemcutter, at least for now, at gemcutter.org/gems/nbudin-version_fu
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acts_as_versioned by Rick Olson github.com/technoweenie/acts_as_versioned/tree/master