openproject/lib/api/v3/utilities/endpoints/bodied.rb

#-- copyright
# OpenProject is a project management system.
# Copyright (C) 2012-2018 the OpenProject Foundation (OPF)
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License version 3.
#
# OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
# Copyright (C) 2006-2017 Jean-Philippe Lang
# Copyright (C) 2010-2013 the ChiliProject Team
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
#
# See docs/COPYRIGHT.rdoc for more details.
#++

module API
  module V3
    module Utilities
      module Endpoints
        class Bodied
          def default_instance_generator(_model)
            raise NotImplementedError
          end

          def default_params_modifier
            ->(params) do
              params
            end
          end

          def initialize(model:,
                         instance_generator: default_instance_generator(model),
                         params_modifier: default_params_modifier,
                         process_service: nil,
                         parse_service: API::V3::ParseResourceParamsService)
            self.model = model
            self.instance_generator = instance_generator
            self.params_modifier = params_modifier
            self.parse_representer = deduce_parse_representer
            self.render_representer = deduce_render_representer
            self.process_contract = deduce_process_contract
            self.process_service = process_service || deduce_process_service
            self.parse_service = parse_service
          end

          def mount
            update = self

            -> do
              params = update.parse(current_user, request_body)

              params = instance_exec(params, &update.params_modifier)

              call = update.process(current_user,
                                    instance_exec(params, &update.instance_generator),
                                    params)

              update.render(current_user, call) do
                status update.success_status
              end
            end
          end

          def parse(current_user, request_body)
            parse_service
              .new(current_user,
                   model: model,
                   representer: parse_representer)
              .call(request_body)
              .result
          end

          def process(current_user, instance, params)
            args = { user: current_user,
                     contract_class: process_contract }

            args[demodulized_name.underscore.to_sym] = instance

            process_service
              .new(args.compact)
              .call(params)
          end

          def render(current_user, call)
            if success?(call)
              yield
              present_success(current_user, call)
            else
              present_error(call)
            end
          end

          def success_status
            :ok
          end

          attr_accessor :model,
                        :instance_generator,
                        :parse_representer,
                        :render_representer,
                        :params_modifier,
                        :process_contract,
                        :process_service,
                        :parse_service

          private

          def present_success(_current_user, _call)
            raise NotImplementedError
          end

          def present_error(_call)
            raise NotImplementedError
          end

          def success?(call)
            call.success?
          end

          def deduce_process_service
            "::#{deduce_namespace}::SetAttributesService".constantize
          end

          def deduce_process_contract
            "::#{deduce_namespace}::#{update_or_create}Contract".constantize
          end

          def deduce_parse_representer
            "::API::V3::#{deduce_namespace}::#{demodulized_name}PayloadRepresenter".constantize
          end

          def deduce_render_representer
            raise NotImplementedError
          end

          def deduce_namespace
            demodulized_name.pluralize
          end

          def demodulized_name
            model.name.demodulize
          end

          def update_or_create
            raise NotImplementedError
          end
        end
      end
    end
  end
end