ActiveModel::WithConditions

Adds with_conditions to Rails apps, or other projects using Active Model or Active Record.

with_conditions is like Active Support's with_options, but only supports :if and :unless, and it merges these.

So you can do:

with_conditions(if: :feature_x_is_on?) do
  validate :free_plans_must_have_x, if: :free_plan?
end

It supports all forms of :if and :unless – symbols, lambdas (with or without a block argument), and arrays of the same.

This improves on Active Support's with_options, where the inner :if would overwrite the outer one, and you'd need to work around it with something like:

with_options(unless: -> { !feature_x_is_on? }) do
  validate :free_plans_must_have_x, if: :free_plan?
end

You can still use with_options for other things (though this gem's author only ever uses it for validation and callback conditions). You could even combine them:

with_conditions(if: :feature_x_is_on?) do
  with_options(presence: true) do
    validates :x
  end
end

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

$ bundle add activemodel-with_conditions

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

$ gem install activemodel-with_conditions

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome at https://github.com/henrik/activemodel-with_conditions.

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