This gem provides a shorthand DSL for including re-usable sets of mixin modules across a large set of STI models. If you find yourself with a folder of subclasses full of boilerplate and shared functionality, this gem will let you replace those files with one or a few small files that read more descriptively, like so:
MySuperClass.describe_descendants_with(MySuperClassMixins) do type :some_type type :another_subtype do email_addressable end type :some_domain_event do email_addressable payment_validatable end end
TL;DR imagine the example in the usage section with a marketplace's domain described therein.
Add this line to your application's Gemfile:
And then execute:
Or install it yourself as:
$ gem install descendants_describable
Here's the real-world example that gave life to this gem:
# config/initializers/activities.rb Activity.describe_descendants_with(Activity::Descriptors) do type :completed_survey do user_required end type :bid_on_developer do approved_employers_only target_required end type :auction_membership_confirmed do approved_developers_only actor_unique_to_auction target_required end # ... others omitted for brevity ... end
Given this example, one is describing the descendants of an Activity class (that also live on the activities table with a type column for STI), the following is happening.
- Each "type" declaration instantiates a new subclass by that name camelized.
- Each method called inside the block provided to a "type" declaration will include into that new subclass a module by that method name camelized in the provided descriptor namespace.
So the above is basically shorthand for this:
# in models/completed_survey.rb class CompletedSurvey < Activity include Activity::Descriptors::UserRequired end # in models/bid_on_developer.rb class BidOnDeveloper < Activity include Activity::Descriptors::ApprovedEmployersOnly include Activity::Descriptors::TargetRequired end # in models/auction_membership_confirmed.rb class AuctionMembershipConfirmed < Activity include Activity::Descriptors::ApprovedEmployersOnly include Activity::Descriptors::ActorUniqueToAuction include Activity::Descriptors::TargetRequired end
You should put any calls to
describe_descendants_with somewhere where it will only be executed
once per boot of your app (including code reloading), such as an initializer(s). This is because
each time you call
describe_descendants_with, a hook is registered with Rails via
ActiveSupport::Reloader.to_run; you don't want to register duplicate reload hooks.
- Fork it
- Create your feature branch (
git checkout -b my-new-feature)
- Commit your changes (
git commit -am 'Add some feature')
- Push to the branch (
git push origin my-new-feature)
- Create new Pull Request