ActiveRecord::EjectionSeat

Sometimes, you want to convert from an ActiveRecord model to something more akin to a simple data class. Enter Sorbet's T::Struct. This gem helps to eject out of bulky ActiveRecord models (or buckle into them) and work with simple T::Struct's in the rest of your app.

For more information about the "why" behind this gem, check out this post.

Install the gem and add to the application's Gemfile by executing:

$ bundle add activerecord-ejection_seat

If bundler is not being used to manage dependencies, install the gem by executing:

$ gem install activerecord-ejection_seat

Let's say you have an ActiveRecord model for a User with a string name column, an integer age column, a role enum column and a belongs to association with a Location model. Another way to express this would be a User type that is a simple, typed struct with other supporting structs.

module Types
  class UserRoles < T::Enum
    enums do
      Admin = new("admin")
      Member = new("member")
    end
  end

  class Location < T::Struct
    const :name, String
  end

  class User < T::Struct
    const :name, String
    const :age, Integer
    const :role, UserRoles
    const :location, Location
  end
end

In our model, we can specify an ejection to this type.

class User
  belongs_to :location
  enum :role, { admin: "admin", member: "member" }

  ejects_to Types::User
end

Now, we have two new methods available on User. First, we can eject from a User instance to a Types::User.

location = Location.new(name: "Florida")
User.new(name: "Max", age: 28, role: "admin", location: location).eject
# => Types::User(name: "Max", age: 28, role: Types::UserRoles::Admin, location: Types::Location.new(name: "Florida))
User.new(name: "Max", age: 28, role: "admin", location: location).to_struct # alias

Second, we can buckle into the User model with a Types::User.

user_struct = Types::User.new(name: "Max", age: 28, role: Types::UserRoles::Admin, location: Types::Location.new(name: "Florida"))
User.buckle(user_struct)
# => User(name: "Max", age: 28, role: "admin", location: Location(name: "Florida"))
User.from_struct(user_struct) # alias

After checking out the repo, run bin/setup to install dependencies. Then, run rake to run Rubocop and the tests. You can also run bin/console for an interactive prompt that will allow you to experiment. You'll need a schema to test ActiveRecord against. Check out spec/spec_helper.rb for an example setup.

To install this gem onto your local machine, run bundle exec rake install.

Bug reports and pull requests are welcome on GitHub at https://github.com/maxveldink/activerecord-ejection_seat. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

The gem is available as open source under the terms of the MIT License.

Everyone interacting in this project's codebase, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

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