[RUBY] Return the execution result of Service class in ServiceResponse class

Introduction

Until now, the execution result of the service class has been fairly appropriate.

For example, it returned the number of updates, and whether it was successful or not, with true and false, and so on.

In GitLab, I created a class called ServiceResponse and used it to return the response of the execution result, and I thought it was very good, so I will summarize it.

contents

In GitLab, it was as follows.

https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/services/service_response.rb

# frozen_string_literal: true

class ServiceResponse
  def self.success(message: nil, payload: {}, http_status: :ok)
    new(status: :success, message: message, payload: payload, http_status: http_status)
  end

  def self.error(message:, payload: {}, http_status: nil)
    new(status: :error, message: message, payload: payload, http_status: http_status)
  end

  attr_reader :status, :message, :http_status, :payload

  def initialize(status:, message: nil, payload: {}, http_status: nil)
    self.status = status
    self.message = message
    self.payload = payload
    self.http_status = http_status
  end

  def success?
    status == :success
  end

  def error?
    status == :error
  end

  def errors
    return [] unless error?

    Array.wrap(message)
  end

  private

  attr_writer :status, :message, :http_status, :payload
end

How to use

If successful

ServiceResponse.success(message: 'success!')

Is set as the return value when the service class is executed,

If it fails

ServiceResponse.error(message: 'failed')

Is set as the return value when the service class is executed.

You can check the status as shown below.

response = ServiceResponse.success(message: 'success!')

response.success? #=> true
response.error? #=> false
response.status #=> :success
response.message #=> 'success!'

On the controller side

result = ArticleUpdateService.new(@article, params).call

if result.success?
  redirect_to article_path(@article), notice: result.message
elsif result.error?
  render :new, alert: result.message
end

You can divide the process depending on whether it succeeds or fails.