The Blame Game

January 5th, 2009

In just about every Rails project I’ve worked on over the last several years we’ve needed track the user who creates and updates database records. The most popular solution seems to be DeLynn Berry’s userstamp plugin and, until recently, that’s what we’ve always chosen to use too. But after fighting incompatibility with newer versions of Rails I decided to write my own plugin. Enter Blame.

Blame automatically userstamps create and update operations if the table has columns named created_by and/or updated_by.

Installation:

ruby script/plugin install git://github.com/infused/blame.git

Blame assumes that you are using restful-authentication and expects User.current_user to return the current user. You can override this behavior by overriding the default userstamp_object method in ActiveRecord::Base or in any of your models. For example, maybe you just want to find the current user bases on the a session variable:

:::ruby
# In environment.rb
class ActiveRecord::Base
  def userstamp_object
    User.find(session[:user_id])
  end
end

Maybe you don’t like the default column names of created_by/updated_by. You can customize the column names globally or for individual models:

:::ruby
# Globally in environment.rb
ActiveRecord::Base.created_userstamp_column = :creator_id

# In a model definition
class Subscription
  self.created_userstamp_column = :creator_id
  self.updated_userstamp_column = :updater_id
end

Automatic userstamping can be turned off by setting record_userstamps:

:::ruby
# Globally in environment.rb
ActiveRecord::Base.record_userstamps = false

# In a model definition
class Subscription
  self.record_userstamps = false
end

Blame also adds a migration helper which will add the created_by and updated_by columns (or your custom column names) to your table:

:::ruby
create_table :widgets do |t|
  t.string :name
  t.timestamps
  t.userstamps
end