AttrTracker

Allows tracking of changes to an attribute.

Suppose you need to track the changes to the price of a product. Each update to the price (or any tracked attribute) creates a new instance of AttrTracker::Changes. Calling product.price_changes returns all of the price changes for the product.

Getting Started

Add AttrTracker to your Gemfile:

gem 'attr_tracker', github: 'iamkevinlowe/attr_tracker'

Run bundle install to download and install the gem, then rake db:migrate to set up AttrTracker's tables.

Note: Reset your server if your application is currently running.

Usage

To start tracking an attribute, add the following to your model's class:

class Product
  tracks :price # accepts any number of valid attributes
end

Class Methods

AttrTracker adds a class method to return all attributes of the class that are currently tracked.

• ::tracked - Returns an array of the tracked attributes.

  Product.tracked => [:price]

Instance Methods

AttrTracker adds methods to an instance of a class to retrieve its changes.

• #{attribute}_changes - Returns all AttrTracker::Changes of an attribute

  eggs.price_changes => [{before: 2.50, after: 2.75, created_at: 2014-10-15},
                         {before: 2.75, after: 2.99, created_at: 2014-10-31},
                         {before: 2.99, after: 3.25, created_at: 2014-11-01},
                         {before: 3.25, after: 3.50, created_at: 2014-11-15}]

• #{attribute}_at(date) - Returns the most recent AttrTracker::Change before the given date.

  eggs.price_at("2014-10-31") => {before: 2.75, after: 2.99, created_at: 2014-10-31}

• #{attribute}_between(start_date, end_date) - Returns the AttrTracker::Changes between the given dates

  eggs.price_between("2014-10-30", "2014-11-02") => [{before: 2.75, after: 2.99, created_at: 2014-10-31},
                                                     {before: 2.99, after: 3.25, created_at: 2014-11-01}]