store_method

This gem offers very simple approach to cache heavy ActiveRecord instance methods in the database. You just add corresponding field to the database, add store_method line and then just drink your coffee, no other changes needed!

Heavy methods are methods which consume some time and resources to compute their returned value. If that value does not change over time, storing it to the database is a good idea. Actually this functionality is very similar to existing cachethod, cache_method and method_cacheable gems, but all those gems are using Rails.cache to store computed values. In case if you don't want to bother with Rails.cache, use store_method to store computed values right in the database, it's clean and simple!

In Gemfile

gem 'store_method', github: 'fomichov/store_method'

Then run

bundle install

Consider gravatar_url instance method which fetches corresponding Gravatar URL for User. This method always takes some time to request www.gravatar.com API so let's store its returned value in the corresponding database field.

class User < ActiveRecord::Base
  def gravatar_url
    ...
  end
end

First create corresponding database field

rails g migration AddGravatarURLToUsers gravatar_url:string

Notice 1: Database column type should match the type that our method returns, any valid column type is supported Notice 2: Assigning default value for the database field will break the logic of this gem because we assume that initial value of every database record is NULL.

Then add store_method call with a method name

class User < ActiveRecord::Base
  store_method :gravatar_url

  def gravatar_url
    ...
  end
end

Passing multiple method names is also supported:

store_methods :gravatar_url, :friends_count

In case if you need to refresh stored value, call stored method with "refresh_" prefix like this:

user = User.first
user.refresh_gravatar_url
SQL (5.7ms)  UPDATE `users` SET `users`.`gravatar_url` = 'http://www.gravatar.com/avatar/fc383b8294226d72f3a7828eeef86987?d=https%3A%2F%2Fidenticons.github.com%2Ffc383b8294226d72f3a7828eeef86987.png&s=42' WHERE `users`.`id` = 1
 => "http://www.gravatar.com/avatar/fc383b8294226d72f3a7828eeef86987?d=https%3A%2F%2Fidenticons.github.com%2Ffc383b8294226d72f3a7828eeef86987.png&s=42" 

Calling stored method with arguments passes these arguments to original method:

class Item < ActiveRecord::Base
  store_method :friends_count

  def friends_count(degree = 1)
    ...
  end
end

This call returns default (stored) value:

user.friends_count
 => 
 100

This call returns new value calculated using degree argument:

user.friends_count(5)
 => 
 100500

Notice that passing argument won't update stored value.

• Implement some checks to ensure that method names match DB columns
• Implement some automation for adding new DB fields

• Check out the latest master to make sure the feature hasn't been implemented or the bug hasn't been fixed yet.
• Check out the issue tracker to make sure someone already hasn't requested it and/or contributed it.
• Fork the project
• Implement your fix or feature
• Add tests for your changes and make sure that all tests are passing
• Post a pull request

This library is distributed under the Beerware license.