Flash

[jodosha]

Private mechanism to send data across requests.

Use case

require 'lotus/controller'

module Comments
  class Index
    include Lotus::Action
    include Lotus::Action::Session

    expose :comments

    def call(params)
      @comments = CommentRepository.all
    end
  end

  class Create
    include Lotus::Action
    include Lotus::Action::Session

    params do
      param :text, type: String, presence: true
    end

    def call(params)
      comment = Comment.new(params)
      CommentRepository.create(comment) if params.valid?

      redirect_to '/comments'
    end
  end
end

The validation errors caused by Comments::Create are available after the redirect in the context of Comments::Index.

Technical details

• It uses unique request ID to store the data that we set
• It's aware of the current request ID
• When finalized (at the end of the request), it removes all the data that doesn't belong to the current request
• If after the finalization, there is no data left, it removes the flash entirely from the session.
• It introduces Lotus::Action::Glue which was written initially for testing purposes, but then I decided to introduce it in favor of the monkey patching that we do in Lotus.
• This isn't a complete solution that we want to expose to developers, but at least it helps with the use case described.

Again, this is marked as private API.

Closes #10

[coveralls]

Coverage increased (+0.13%) when pulling 5322d63 on flash into 257459e on master.