Rails 5 manage result from monads - ruby-on-rails

Question

I've got Rails 5 app with dry-monads on board. Monads are used to create the Appointment object inside create action in AppointmentsController. They return Success or Failure in the last step with below structure:
# services/appointments/create.rb
(...)
def call
Success(appointment_params: appointment_params)
(...)
.bind(method(:save_appointment))
end
private
def save_appointment(appointment)
if appointment.save
Success(appointment)
else
Failure(failure_appointments: appointment, appointments_errors: appointment.errors.full_messages)
end
end
After each action (success or failure) I want to send an email and display the corresponding json in AppointmentsController:
class Api::AppointmentsController < ApplicationController
def create
succeeded_appointments = []
failure_appointments = []
appointments_errors = []
batch_create_appointments_params[:_json].each do |appointment_params|
appointment = ::Appointments::Create.new(appointment_params).call
if appointment.success?
succeeded_appointments << appointment.value!
else
failure_appointments << appointment.failure[:failure_appointments] &&
appointments_errors << appointment.failure[:appointments_errors]
end
end
if failure_appointments.any?
AppointmentMailer.failed_mail(email, failure_appointments.size, appointments_errors).deliver_now
render json: {
error: appointments_errors.join(', '),
}, status: :bad_request
elsif succeeded_appointments.any?
AppointmentMailer.success_mail(email, succeeded_appointments.size).deliver_now
render json: {
success: succeeded_appointments.map do |appointment|
appointment.as_json(include: %i[car customer work_orders])
end,
}
end
end
I wonder if there is a better, faster way to record these errors than declaring 3 different empty arrays (succeeded_appointments, failure_appointments, appointments_errors) like at the beginning of create action? so far the create action looks heavy.

Answer 1

Create a separate service object for bulk creation:
# services/appointments/bulk_create.rb
class Appointments::BulkCreate
def initialize(bulk_params)
#bulk_params = bulk_params
end
def call
if failed_results.any?
AppointmentMailer.failed_mail(email, failed_results_errors.size, failed_results_errors).deliver_now
Failure(failed_results_errors.join(', '))
else
AppointmentMailer.success_mail(email, success_appointments.size).deliver_now
Success(success_appointments)
end
end
private
attr_reader :bulk_params
def failed_results
results.select(&:failure?)
end
def success_results
results.select(&:success?)
end
def success_appointments
#success_appointments ||= success_results.map do |appointment|
appointment.as_json(include: %i[car customer work_orders])
end
end
def failed_results_errors
#failed_results_errors ||= failed_results.map do |failed_result|
failed_result.failure[:appointments_errors]
end
end
def results
#results ||= bulk_params.map do |appointment_params|
::Appointments::Create.new(appointment_params).call
end
end
end
Then your controller will look like this:
class Api::AppointmentsController < ApplicationController
def create
result = ::Appointments::BulkCreate.new(batch_create_appointments_params[:_json]).call
if result.success?
render json: { success: result.value! }, status: :ok
else
render json: { error: result.failure }, status: :bad_request
end
end
end