Ruby - Moving rails 'business logic' into service modules

Question

I want to move some rails business logic into a service, following correct OOP protocol. I'm following the method recommended here: Private module methods in Ruby

Ultimately, I want to move business logic out of models and controllers into services, which are Plain Old Ruby Objects. So, models will just be concerned with persistence, scoping, & validation.

Is this the correct way to make a service module?

Version 2:

module CategorizeJobs

  def self.fetch( location, category_name )
    c = Categorizer.new( location, category_name )
    c.get_jobs
  end

  class Categorizer

    def initialize(location, category_name)
      @location = location
      @category_name = category_name
    end

    def get_jobs
      job_ids = get_correct_jobs
      Category.includes(:jobs).where( jobs: { id:  job_ids } )
    end

    private

      def get_correct_jobs
        jobs = filter_by_location
        jobs = filter_by_category(jobs)

        jobs.collect(&:id)
      end

      def filter_by_category(jobs)
        return jobs unless @category_name.present?

        category = Category.where(name: @category_name).first
        if category
          jobs = jobs.where(category: category)
        end

        jobs
      end

      def filter_by_location
        if @location.present?
          jobs = get_jobs_at_location
        else
          jobs = Job.open
        end
      end

      def get_jobs_at_location(location)
        Job.joins(:location).within(20, origin: @location).open
      end

  end

end

Version 1:

 module CategorizeJobs

  def self.fetch( location, category_name )
    c = Categorizer.new
    c.perform( location, category_name )
  end


  class Categorizer

    def perform( location, category_name )
      job_ids = get_correct_jobs(location, category_name)
      Category.includes(:jobs).where( jobs: { id:  job_ids } )
    end

    private

      def get_correct_jobs(location, category_name)
        jobs = filter_by_location(location)
        jobs = filter_by_category(jobs, category_name)

        jobs.collect(&:id)
      end

      def filter_by_category(jobs, category_name)
        return jobs unless category_name

        category = Category.where(name: category_name).first
        if category
          jobs = jobs.where(category: category)
        end

        jobs
      end

      def filter_by_location(location)
        if location
          jobs = get_jobs_at_location(location)
        else
          jobs = Job.open
        end
      end

      def get_jobs_at_location(location)
        Job.joins(:location).within(20, origin: location).open
      end

  end

end

Oops - deleted it by accident! "Is this the correct way to make a service module?" — Will Taylor, May 14 '15 at 10:33
You're always passing around location and category name. Why not create an initializer and store them in variables so you don't need to pass them around? — j-dexx, May 14 '15 at 10:39

score 3 · Answer 1 · answered May 14 '15 at 11:22

3

There is a gem by the name of Aldous that helps you implement service objects based architecture into your Rails applications. Have a look at it.

If you need further help on how to use it and architect your application, you can look at this and this for more help.

answered May 14 '15 at 11:22

Noman Ur Rehman

6,707
3
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Thanks! Had a read through - good idea. I don't think I want to completely re-architect my app, I have no idea how this will work with other gems I'm using - and I'll have to train any developers I bring onto the project in Aldous – Will Taylor May 14 '15 at 11:33
@WillTaylor No need to re-architect your app or take the learning curve to implement the gem. Just understand how service objects are implemented through those resources and hack away your project. – Noman Ur Rehman May 14 '15 at 13:10

Ruby - Moving rails 'business logic' into service modules

1 Answers1