ruby 50 lines · 1 tab

Service objects for complex business logic

Alex Kumar Jan 2026

1 tab

class CreatePostService
  def initialize(author:, params:)
    @author = author
    @params = params
  end

  def call
    post = nil

    ActiveRecord::Base.transaction do
      post = @author.posts.create!(@params)

      # Notify followers in background
      NotifyFollowersWorker.perform_async(post.id) if post.published?

      # Update author stats
      @author.increment!(:posts_count)
    end

    Result.success(post: post)
  rescue ActiveRecord::RecordInvalid => e
    Result.failure(errors: e.record.errors)
  rescue StandardError => e
    Rails.logger.error("CreatePostService failed: #{e.message}")
    Result.failure(error: 'INTERNAL_ERROR')
  end

  class Result
    attr_reader :post, :errors, :error

    def initialize(success:, post: nil, errors: nil, error: nil)
      @success = success
      @post = post
      @errors = errors
      @error = error
    end

    def success?
      @success
    end

    def self.success(post:)
      new(success: true, post: post)
    end

    def self.failure(errors: nil, error: nil)
      new(success: false, errors: errors, error: error)
    end
  end
end

1 file · ruby Explain with highlit

As business logic grows, controllers become bloated with transaction management, error handling, and cross-model orchestration. Service objects extract this complexity into dedicated classes with a single public method (usually call), keeping controllers thin and focused on HTTP concerns. Each service object represents one business operation like CreateOrder or ProcessRefund. I pass dependencies explicitly rather than hiding them in class methods, which makes testing straightforward—I can stub external services without touching global state. Service objects also centralize logging and metrics collection for business-critical operations. The pattern works best when each service has a clear input contract and returns a result object indicating success or failure with relevant data.

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