hanami 2 action with dry-validation

create.rb

module MySlice
  module Actions
    module Thing
      class CreateContract < Dry::Validation::Contract
        params do
          required(:name).filled(:str?)
          optional(:email).maybe(:str?)
        end

        rule(:email) do
          # custom logic here e.g.
          # key.failure("must be a valid email") unless value.match?(/@/)
        end
      end

      class Create < Action
        include Deps[repo: "repositories.thing"]

        before :validate

        params do
          required(:thing).schema do
            required(:name).filled(:str?)
            optional(:email).maybe(:str?)
          end
        end

        def handle(request, response)
          case repo.create(response[:contract].to_h)
          in {id: Integer} => thing
            response.redirect_to routes.path(
              :next_step,
              id: thing.id
            )
          else
            failure(request, response)
          end
        end

        private def failure(request, response)
          halt 422, response.render(
            view,
            thing: request.params[:thing],
            errors: response[:contract].errors.to_h
          )
        end

        private def validate(request, response)
          response[:contract] = CreateContract.new.call(request.params[:thing])

          failure(request, response) unless response[:contract].success?
        end
      end
    end
  end
end