Simple template for migrating your rails ActiveRecord::Store's from YAML to JSON

migrate-yaml-store-to-json.rb

# Override your existing class with a simple replacement class
class Token < ActiveRecord::Base
end

class ConvertStoresToJson < ActiveRecord::Migration
  def process(value)
    if value && !value.starts_with?("{")
      result = YAML.load(value).to_json
    else
      result = value
    end

    say "\t#{value} => #{result}"

    result
  end

  def up
    # Only select what we need to avoid any additional complications
    Token.select([:id, :permissions, :options]).find_each do |token|
      say "Converting #{token.id}..."
      token.permissions = process(token.permissions_before_type_cast)
      token.options = process(token.options_before_type_cast)
      token.save!
    end
  end

  def down
  end
end

# Run `bundle exec rake db:migrate` and update your stores `store :settings, :coder => JSON`