CheckOut

Let users check out Active Record instances and then release them when they're done editing.

Using include CheckOut in a model's class definition provides the following features:

• Scopes:
  1. checked_out_to(user)
  2. checked_out
  3. released (inverse of checked_out)
  4. available_to(user)
• Collection / scope methods:
  1. check_out_all(user)
  2. release_all_checkouts(user) (user is optional)
• Instance methods:
  1. checked_out?
  2. checked_out_to?(user)
  3. check_out(user)
  4. release(user) (user is optional)
  5. update_attributes_and_release(attributes)

The model must have the following columns:

• checked_out_by_user_id (integer)
• checked_out_by_user_type (string)
• checked_out_at (datetime)

Requires Rails ~> 3 and Ruby 1.9.2.

Usage

create_table "jobs" do |t| t.integer :checked_out_by_user_id t.string :checked_out_by_user_type t.datetime :checked_out_at end

class Job < ActiveRecord::Base include CheckOut end

# in 'edit' action

job.checkout(user) # => job.checked_out_at = Time.now, etc.

# in 'update' action

job = Job.available_to(user).find(params[:id]) job.update_attributes_and_release(params[:job])

The challenging thing is knowing when to release the record if the user decides not to make any changes (i.e. cancels) or just closes their browser.

I've found that by including Job.release_all_checkouts(current_user) in the 'index' action, I can avoid almost all conflicts. I also add an "unlock" action for manually overriding an existing checkout. A link to 'unlock' appears in a flash message if a user tries to edit a record that is already checked out.