Cachethod

With this Rails plugin you can cache your model methods and speed up obtaining results. This can be very useful when you are doing some expensive operations (eg. reading from file or doing some http request) in your model methods and you don't need fresh results every time you invoke the method or results just don't change so frequently.

Works out of box with Rails 3 and Rails 4.

About

It wraps Rails.cache.fetch method so it is completely without configuration and if you change cache configuration of your project it will be reflected also on Cachethod methods.

Install

In Gemfile

gem 'cachethod', '~> 0.2.0'

Then run

bundle install

Usage

First step is including Cachethod module to your class.

class User < ActiveRecord::Base
  include Cachethod

  ...
end

Next you can choose one of following methods:

cache_method :method_name, expires_in: 1.minutes
cachethod :method_name, expires_in: 2.days
cache_methods [:method1_name, :method2_name], expires_in: 3.weeks
cachethods [:method2_name, :method2_name], expires_in: 4.months

First argument is name of the method you want to cache and other arguments are the same that you are used to pass on Rails.cache.fetch method.

Just put it in your controller:

class User < ActiveRecord::Base
  include Cachethod

  cache_method :some_io_method, expires_in: 10.minutes

  def some_io_method arg1
    ...
  end
end

Then invoke cached method multiple times in the usual way and you will see the difference:

user.some_io_method(2) # this will take a long time
user.some_io_method(2) # you get cached result instantly
user.some_io_method(3) # this will take a long time again
user.some_io_method(3) # you get cached result instantly
user.some_io_method(2) # you get cached result instantly

Note that Cachethod takes method arguments into the account and when you change arguments it will need to cache method result also.

If you want to access uncached version of your method then you can do:

user.some_io_method!

Caching class methods

class Apple < ActiveRecord::Base
  include Cachethod

  class << self
    def kinds
      ...
    end
  end

  cache_class_method :kinds, expires_in: 10.minutes
end

Result

For example it translates following code:

class Stormtrooper
  include Cachethod

  cache_methods [:some_io_method, :another_io_method], expires_in: 10.minutes

  def some_io_method
    ...
  end

  def another_io_method
    ...
  end
end

into the equivalent of:

class Stormtrooper < ActiveRecord::Base
  def some_io_method *args
    Rails.cache.fetch(:some_key, expires_in: 10.minutes) do
      ...
    end
  end

  def another_io_method *args
    Rails.cache.fetch(:another_key, expires_in: 10.minutes) do
      ...
    end
  end
end

License

This library is distributed under the Beerware license.

cachethod

Development