DROP YOUR app/services! Vladimir Dementyev Evil Martians 

! Find 2 hot takes on this slide 

! Find 2 hot takes on this slide " Rails' MVC is not MVC " You don't need a server to run a Rails app #WASM 

RAILS WAY Canonical examples tree -d -L 1 fizzy/app fizzy/app/ ├── assets ├── channels ├── controllers ├── helpers ├── javascript ├── jobs ├── mailers ├── models └── views 10 directories ➜ tree -d -L 1 writebook/app writebook/app/ ├── assets ├── channels ├── controllers ├── helpers ├── javascript ├── jobs ├── mailers ├── models └── views 10 directories ➜ tree -d -L 1 campfire/app campfire/app/ ├── assets ├── channels ├── controllers ├── helpers ├── javascript ├── jobs ├── models └── views 9 directories ➜ Folders are categories 

Where do I put this? app/models app/controllers 

➜tree -d -L 1 random-rails-app/app RAILS WAY Real life, though... 

➜ tree -d -L 1 random-rails-app/app random-rails-app/app/ ├── assets ├── controllers ├── ... ├── mailers ├── models ├── services ├── ... └── views 18 directories RAILS WAY Real life, though... ➜ tree -d -L 1 another-rails-app/app another-rails-app/app/ ├── controllers ├── graphql ├── ... ├── models ├── services ├── ... ├── views └── workers 14 directories ➜ tree -d -L 1 one-more-rails-app/app one-more-rails-app/app/ ├── assets ├── channels ├── controllers ├── javascript ├── jobs ├── models ├── services └── views 8 directories 

➜ tree -d -L 1 random-rails-app/app random-rails-app/app/ ├── assets ├── controllers ├── ... ├── mailers ├── models ├── services ├── ... └── views 18 directories RAILS WAY Real life, though... ➜ tree -d -L 1 another-rails-app/app another-rails-app/app/ ├── controllers ├── graphql ├── ... ├── models ├── services ├── ... ├── views └── workers 14 directories ➜ tree -d -L 1 one-more-rails-app/app one-more-rails-app/app/ ├── assets ├── channels ├── controllers ├── javascript ├── jobs ├── models ├── services └── views 8 directories 

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WHAT IS SERVICE OBJECT? 

“Service is a standalone operation within the context of your domain. Service Object collects one or more services into an object” –Eric Evans, DDD 

“A Service Layer defines an application's boundary and encapsulates the application's business logic, controlling transactions and coordinating responses in the implementation of its operations” –Martin Fowler 

–(Most) Rails devs “A callable PORO lying in between controllers and models.” 

“If it doesn't fit anywhere, put it into app/services.” –Also (most) Rails devs 

“If it doesn't fit anywhere, put it into app/services.” –Also (most) Rails devs Stop thinking in folders, think in abstractions! 

github.com/palkan 

evilmartians.com 

evilmartians.com/events 

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“The app/services folder could be seen as a waiting room for code.” 

THE WAITING ROOM From faceless objects to specialized abstractions 

THE WAITING ROOM Start with faceless service objects just for the sake of separation of concerns 

THE WAITING ROOM Start with faceless service objects just for the sake of separation of concerns Decompose app/services into specialized abstractions as the codebase evolves 

THE WAITING ROOM Start with faceless service objects just for the sake of separation of concerns Decompose app/services into specialized abstractions as the codebase evolves Most teams stop here 

DROP THEIR APP/SERVICES 

DROP THEIR APP/SERVICES 5 OSS Rails apps Different products, different generations, different patterns All with the app/services waiting rooms worth sorting out Examples of misused/overused/underused services 

RANDOM JUNK DROP CANDIDATES #1 

RANDOM JUNK Pure infra wrappers View helpers Useless extractions Developer tools Truly random stuff Objects not even pretending to be services 

# app/services/utils/pdf_attachment_service.rb module Utils class PdfAttachmentService < BaseService def initialize(file:, attachment:) @file = file @attachment = attachment super end def call return result.not_found_failure!(resource: "file") unl return result.not_allowed_failure!(code: "not_a_pdf_fi success = Kernel.system("pdfcpu", "attach", "add", fil if success result.file = file else result.third_party_failure!(third_party: "pdfcpu", e end result end private attr_reader :file, :attachment end end CLI wrapper No app-specific logic 

# app/services/utils/pdf_attachment_service.rb module Utils class PdfAttachmentService < BaseService def initialize(file:, attachment:) @file = file @attachment = attachment super end def call return result.not_found_failure!(resource: "file") unl return result.not_allowed_failure!(code: "not_a_pdf_fi success = Kernel.system("pdfcpu", "attach", "add", fil if success result.file = file else result.third_party_failure!(third_party: "pdfcpu", e end result end private attr_reader :file, :attachment end end CLI wrapper No app-specific logic Uses BaseService interface (result) → not used! 

# app/services/utils/pdf_attachment_service.rb module Utils class PdfAttachmentService < BaseService def initialize(file:, attachment:) @file = file @attachment = attachment super end def call return result.not_found_failure!(resource: "file") unl return result.not_allowed_failure!(code: "not_a_pdf_fi success = Kernel.system("pdfcpu", "attach", "add", fil if success result.file = file else result.third_party_failure!(third_party: "pdfcpu", e end result end private attr_reader :file, :attachment end end CLI wrapper No app-specific logic Uses BaseService interface (result) → not used! ↳ Demote to app/lib 

# app/services/utils/pdf_attachment_service.rb module Utils class PdfAttachmentService < BaseService def initialize(file:, attachment:) @file = file @attachment = attachment super end def call return result.not_found_failure!(resource: "file") unl return result.not_allowed_failure!(code: "not_a_pdf_fi success = Kernel.system("pdfcpu", "attach", "add", fil if success result.file = file else result.third_party_failure!(third_party: "pdfcpu", e end result end private attr_reader :file, :attachment end end CLI wrapper No app-specific logic Uses BaseService interface (result) → not used! ↳ Demote to app/lib A typical junk drawer 

# app/services/flavor_text_service.rb class FlavorTextService include ActionView::Helpers::NumberHelper def initialize(user: nil, env: Rails.env, deterministic: true) # ... end def generate = sample def development_flavor_texts [ "Hack the Bank Mode", # ~50 phrases ] end def birthday_flavor_texts = [...] # ~50 phrases def holiday_flavor_texts = [...] # ~50 phrases def spooky_flavor_texts = [...] # ~100 phrases def flavor_texts = [...] # ~200 phrases private def sample return development_flavor_texts.sample(random: @random) if dev? return holiday_flavor_texts.sample(random: @random) if winter? return @random.rand > 0.5 ? spooky_flavor_texts.sample(random: @random) : flavor_texts.sample(random: @random) if fall? return birthday_flavor_texts.sample(random: @random) if @user&.birthday? flavor_texts.sample(random: @random) end end Random phrase generator Corpus is embedded into code Knows a bit about a user ↳ app/helpers + config/ locales/flavor.yml 

# app/services/wildcard_url_checker.rb module WildcardUrlChecker def self.check_url(url, url_to_check) return false if !valid_url?(url_to_check) escaped_url = Regexp.escape(url).sub("\\*", ' url_regex = Regexp.new("\\A#{escaped_url}\\z" url_to_check.match?(url_regex) end private def self.valid_url?(url) uri = URI.parse(url) uri&.scheme.present? && uri&.host.present? rescue URI::InvalidURIError false end end Just a predicate method 

# app/services/wildcard_url_checker.rb module WildcardUrlChecker def self.check_url(url, url_to_check) return false if !valid_url?(url_to_check) escaped_url = Regexp.escape(url).sub("\\*", ' url_regex = Regexp.new("\\A#{escaped_url}\\z" url_to_check.match?(url_regex) end private def self.valid_url?(url) uri = URI.parse(url) uri&.scheme.present? && uri&.host.present? rescue URI::InvalidURIError false end end # app/models/user_api_client.rb class UserApiKeyClient < ActiveRecord::Base # ... def self.invalid_auth_redirect?(auth_redirect, clie return false if client&.auth_redirect == auth_red SiteSetting .allowed_user_api_auth_redirects .split("|") .none? { |u| WildcardUrlChecker.check_url(u, au end end Just a predicate method Used in a single model 

# app/services/wildcard_url_checker.rb module WildcardUrlChecker def self.check_url(url, url_to_check) return false if !valid_url?(url_to_check) escaped_url = Regexp.escape(url).sub("\\*", ' url_regex = Regexp.new("\\A#{escaped_url}\\z" url_to_check.match?(url_regex) end private def self.valid_url?(url) uri = URI.parse(url) uri&.scheme.present? && uri&.host.present? rescue URI::InvalidURIError false end end # app/models/user_api_client.rb class UserApiKeyClient < ActiveRecord::Base # ... def self.invalid_auth_redirect?(auth_redirect, clie return false if client&.auth_redirect == auth_red SiteSetting .allowed_user_api_auth_redirects .split("|") .none? { |u| WildcardUrlChecker.check_url(u, au end end Just a predicate method Used in a single model ↳ Demote to a model method 

And more random stuff... 

# app/services/destroy_task.rb require "highline" require "io/console" class DestroyTask def initialize(io = STDOUT) @io = io @tty = IO.console @hl = HighLine.new(@tty, @io) end def destroy_topics(category, parent_category = nil, delete_system_topics = fal # ... end end And more random stuff... A Rake task handler 

# app/services/destroy_task.rb require "highline" require "io/console" class DestroyTask def initialize(io = STDOUT) @io = io @tty = IO.console @hl = HighLine.new(@tty, @io) end def destroy_topics(category, parent_category = nil, delete_system_topics = fal # ... end end # app/utils/timezone.rb module Utils class Timezone def self.at_time_zone_sql(customer: "customers", billing_entity: "billing_en <<-SQL ::timestamptz AT TIME ZONE COALESCE(#{customer}.timezone, #{billing_enti SQL end end end And more random stuff... A Rake task handler... A SQL fragment generator??? 

# app/services/destroy_task.rb require "highline" require "io/console" class DestroyTask def initialize(io = STDOUT) @io = io @tty = IO.console @hl = HighLine.new(@tty, @io) end def destroy_topics(category, parent_category = nil, delete_system_topics = fal # ... end end # app/utils/timezone.rb module Utils class Timezone def self.at_time_zone_sql(customer: "customers", billing_entity: "billing_en <<-SQL ::timestamptz AT TIME ZONE COALESCE(#{customer}.timezone, #{billing_enti SQL end end end # app/services/markdown_scrubber.rb class MarkdownScrubber < Rails::HTML::PermitScrubber def initialize super self.tags = %w(a abbr b blockquote br code dd del div dl dt em h1 h2 h3 h4 h strike strong sub summary sup table tbody td tfoot th thead tr tt ul var) self.attributes = %w(class style href src target alt aria-label) end end And more random stuff... A Rake task handler... A SQL fragment generator??? Custom HTML sanitizer 

# app/services/destroy_task.rb require "highline" require "io/console" class DestroyTask def initialize(io = STDOUT) @io = io @tty = IO.console @hl = HighLine.new(@tty, @io) end def destroy_topics(category, parent_category = nil, delete_system_topics = fal # ... end end # app/utils/timezone.rb module Utils class Timezone def self.at_time_zone_sql(customer: "customers", billing_entity: "billing_en <<-SQL ::timestamptz AT TIME ZONE COALESCE(#{customer}.timezone, #{billing_enti SQL end end end # app/services/markdown_scrubber.rb class MarkdownScrubber < Rails::HTML::PermitScrubber def initialize super self.tags = %w(a abbr b blockquote br code dd del div dl dt em h1 h2 h3 h4 h strike strong sub summary sup table tbody td tfoot th thead tr tt ul var) self.attributes = %w(class style href src target alt aria-label) end end And more random stuff... A Rake task handler... A SQL fragment generator??? Custom HTML sanitizer ↳ not in app/services 

DON'T KEEP JUNK AROUND Improve signal-to-noise ratio / discoverability Ensure dependency direction (presentation → business logic → infra) Avoid false consistency tax Move your codebase to a healthy livable place 

FALSE CONSISTENCY DROP CANDIDATES #2 

FALSE CONSISTENCY A uniform interface across fundamentally different responsibilities SearchService::Parser.new(...).run # parse a query HcbCodeService::CanDispute.new(...).run # a system constraint predicate Decline::OutgoingCheck.new(...).run # reject a payment FlavorTextService.new.run # return a random phrase StripeCardService::Nightly.new.run # update_all on one column SendCardLockingNotification.new(...).run # orchestrate notifications Everything is #run, and #run means nothing 

FALSE CONSISTENCY A uniform interface across fundamentally different responsibilities BillMetrics::EvaluateExpressionService.call(...) # parse + evaluate a DSL expr Analytics::MrrsService.call(...) # license check, simple query AppliedCoupons::LockService.call(...) { ... } # wrap a Postgres advisory lock Auth::SupersetService.call(...) # 200 LOC: auth, CSRF, etc Utils::PdfGenerator.call(...) # render PDF via Gotenberg PDF .call # pure math Everything is .call, and .call means nothing 

# app/services/charge_models/amount_details/range_graduated_service. class < ::BaseService def initialize(range:, total_units:, adjacent_model: false) # ... end def call { from_value:, to_value:, flat_unit_amount:, per_unit_amount:, units: BigDecimal(units).to_s, per_unit_total_amount:, total_with_flat_amount: } end # ... end Just a calculator Uses BaseService (because lives in app/services) 

# app/services/charge_models/amount_details/range_graduated_service. class < ::BaseService def initialize(range:, total_units:, adjacent_model: false) # ... end def call { from_value:, to_value:, flat_unit_amount:, per_unit_amount:, units: BigDecimal(units).to_s, per_unit_total_amount:, total_with_flat_amount: } end # ... end Just a calculator Uses BaseService (because lives in app/services) Inherits all the service machinery! # app/services/base_service.rb class BaseService include AfterCommitEverywhere use(Middlewares::LogTracerMiddleware) use(Middlewares::DatadogMiddleware) def self.call(*, **, &) new(*, **).call_with_middlewares(&) end def call_with_middlewares(&block) chain = init_middlewares chain.call { call(&block) } end # ... end 

# app/services/charge_models/amount_details/range_graduated_service. class < ::BaseService def initialize(range:, total_units:, adjacent_model: false) # ... end def call { from_value:, to_value:, flat_unit_amount:, per_unit_amount:, units: BigDecimal(units).to_s, per_unit_total_amount:, total_with_flat_amount: } end # ... end Just a calculator Uses BaseService (because lives in app/services) Inherits all the service machinery! All other calculators use a hack—#apply! # app/services/base_service.rb class BaseService include AfterCommitEverywhere use(Middlewares::LogTracerMiddleware) use(Middlewares::DatadogMiddleware) def self.call(*, **, &) new(*, **).call_with_middlewares(&) end def call_with_middlewares(&block) chain = init_middlewares chain.call { call(&block) } end # ... end 

# app/services/charge_models/amount_details/range_graduated_service. class < ::BaseService def initialize(range:, total_units:, adjacent_model: false) # ... end def call { from_value:, to_value:, flat_unit_amount:, per_unit_amount:, units: BigDecimal(units).to_s, per_unit_total_amount:, total_with_flat_amount: } end # ... end Just a calculator Uses BaseService (because lives in app/services) Inherits all the service machinery! All other calculators use a hack—#apply! # app/services/base_service.rb class BaseService include AfterCommitEverywhere use(Middlewares::LogTracerMiddleware) use(Middlewares::DatadogMiddleware) def self.call(*, **, &) new(*, **).call_with_middlewares(&) end def call_with_middlewares(&block) chain = init_middlewares chain.call { call(&block) } end # ... end module ChargeModels class BaseService < ::BaseService Result = BaseResult[...] def self.apply(...) new(...).apply end def apply # custom interface end end end module ChargeModels class GroupedService < ChargeModels::BaseService Result = BaseResult[...] def apply # ... end end end module ChargeModels class GraduatedService < ChargeModels::BaseService protected # ... end end 

DON'T TRUST THE INTERFACE Interface should not erase intent Different responsibilities need different shared machinery Consistency for the sake of consistency is harmful Misused abstraction is worse than no abstraction 

SINK HOLES DROP CANDIDATES #3 

SINKHOLE SERVICES DDD (Dogma-Driven Design) class DismissNotificationRequestService < BaseService def call(request) FilteredNotificationCleanupWorker.perform_async( request.account_id, request.from_account_id ) request.destroy! end end 

SINKHOLE SERVICES DDD (Dogma-Driven Design) class DismissNotificationRequestService < BaseService def call(request) FilteredNotificationCleanupWorker.perform_async( request.account_id, request.from_account_id ) request.destroy! end end class Api::V1::Notifications::RequestsController < Api::BaseController def dismiss DismissNotificationRequestService.new.call(@request) render_empty end # ... end 

SINKHOLE SERVICES DDD (Dogma-Driven Design) class AfterUnallowDomainService < BaseService def call(domain) return if domain.blank? Account.remote.where(domain: domain).find_each do |account| DeleteAccountService.new.call(account, reserve_username: false) end end end 

SINKHOLE SERVICES DDD (Dogma-Driven Design) class AfterUnallowDomainService < BaseService def call(domain) return if domain.blank? Account.remote.where(domain: domain).find_each do |account| DeleteAccountService.new.call(account, reserve_username: false) end end end class AfterUnallowDomainWorker include Sidekiq::Worker def perform(domain) AfterUnallowDomainService.new.call(domain) end end Anemic job detected! 

SINKHOLE SERVICES Sometimes they look like honest services class DeleteCollectionService < BaseService def call(collection) @collection = collection collection.destroy! ActivityPub::RawDistributionWorker.perform_async( activity_json, collection.account.id ) end private def activity_json # serialize collection via AMS end end 

SINKHOLE SERVICES Sometimes they look like honest services class YetAnotherService < BaseService def call(...) model.some_operation create_notification if account.activitypub? end private def create_notification ActivityPub::DeliveryWorker.perform_async(activity_json, ...) end def activity_json # serialize collection via AMS end end The pattern appears in 15+ services 

SINKHOLE SERVICES Sometimes they look like honest services class Api::V1Alpha::CollectionsController < Api::BaseController def destroy authorize @collection, :destroy? recording_activity(:remove_featured_collection, @collection) do @collection.destroy! end head 200 end end Replace with a single abstraction 

DON'T BE DOGMATIC A service that makes no decisions adds no value One rich object beats a chain of anemic ones Repeated side effects deserve their own home Overused abstraction is worse than no abstraction 

DOMAIN OBJECTS IN DISGUISE DROP CANDIDATES #4 

dev.37signals.com/vanilla-rails-is-plenty/ We don’t separate application-level and domain-level artifacts. Instead, we have a set of domain models (both Active Records and POROs) exposing public interfaces to be invoked from the system boundaries, typically controllers or jobs 

We use domain services and controllers as orchestrators. We care about reducing solutions to its essence. 

app/models/charge ├── amount_details │ ├── range_graduated_percentage_calculator.rb │ └── range_graduated_calculator.rb ├── base_calculator.rb ├── build_default_properties_calculator.rb ├── custom_calculator.rb ├── dynamic_calculator.rb ├── factory.rb ├── filter_properties │ ├── base_calculator.rb │ ├── charge_calculator.rb │ └── fixed_charge_calculator.rb ├── filter_properties_calculator.rb ├── graduated_percentage_calculator.rb ├── graduated_calculator.rb ├── grouped_calculator.rb ├── package_calculator.rb ├── percentage_calculator.rb ├── prorated_graduated_calculator.rb ├── standard_calculator.rb └── volume_calculator.rb app/services/charge_models ├── amount_details │ ├── range_graduated_percentage_service.rb │ └── range_graduated_service.rb ├── base_service.rb ├── build_default_properties_service.rb ├── custom_service.rb ├── dynamic_service.rb ├── factory.rb ├── filter_properties │ ├── base_service.rb │ ├── charge_service.rb │ └── fixed_charge_service.rb ├── filter_properties_service.rb ├── graduated_percentage_service.rb ├── graduated_service.rb ├── grouped_service.rb ├── package_service.rb ├── percentage_service.rb ├── prorated_graduated_service.rb ├── standard_service.rb └── volume_service.rb 

app/models/charge ├── amount_details │ ├── range_graduated_percentage_calculator.rb │ └── range_graduated_calculator.rb ├── base_calculator.rb ├── build_default_properties_calculator.rb ├── custom_calculator.rb ├── dynamic_calculator.rb ├── factory.rb ├── filter_properties │ ├── base_calculator.rb │ ├── charge_calculator.rb │ └── fixed_charge_calculator.rb ├── filter_properties_calculator.rb ├── graduated_percentage_calculator.rb ├── graduated_calculator.rb ├── grouped_calculator.rb ├── package_calculator.rb ├── percentage_calculator.rb ├── prorated_graduated_calculator.rb ├── standard_calculator.rb └── volume_calculator.rb app/services/charge_models ├── amount_details │ ├── range_graduated_percentage_service.rb │ └── range_graduated_service.rb ├── base_service.rb ├── build_default_properties_service.rb ├── custom_service.rb ├── dynamic_service.rb ├── factory.rb ├── filter_properties │ ├── base_service.rb │ ├── charge_service.rb │ └── fixed_charge_service.rb ├── filter_properties_service.rb ├── graduated_percentage_service.rb ├── graduated_service.rb ├── grouped_service.rb ├── package_service.rb ├── percentage_service.rb ├── prorated_graduated_service.rb ├── standard_service.rb └── volume_service.rb 

app/services/charge_models ├── amount_details │ ├── range_graduated_percentage_service.rb │ └── range_graduated_service.rb ├── base_service.rb ├── build_default_properties_service.rb ├── custom_service.rb ├── dynamic_service.rb ├── factory.rb ├── filter_properties │ ├── base_service.rb │ ├── charge_service.rb │ └── fixed_charge_service.rb ├── filter_properties_service.rb ├── graduated_percentage_service.rb ├── graduated_service.rb ├── grouped_service.rb ├── package_service.rb ├── percentage_service.rb ├── prorated_graduated_service.rb ├── standard_service.rb └── volume_service.rb app/models/charge ├── amount_details │ ├── range_graduated_percentage_calculator.rb │ └── range_graduated_calculator.rb ├── base_calculator.rb ├── build_default_properties_calculator.rb ├── custom_calculator.rb ├── dynamic_calculator.rb ├── factory.rb ├── filter_properties │ ├── base_calculator.rb │ ├── charge_calculator.rb │ └── fixed_charge_calculator.rb ├── filter_properties_calculator.rb ├── graduated_percentage_calculator.rb ├── graduated_calculator.rb ├── grouped_calculator.rb ├── package_calculator.rb ├── percentage_calculator.rb ├── prorated_graduated_calculator.rb ├── standard_calculator.rb └── volume_calculator.rb 

THE ESSENCE This is the Way # Service Objects Way result = ChargeModels::Factory.new_instance( chargeable: charge, **options ).apply advance_model = ChargeModels::Factory.in_advance_charge_model_class(chargeable: charge) # Rails Way result = charge.calculate(**options) advance_calculator = charge.in_advance_calculator 

THE ESSENCE This is the Way # Service Objects Way result = ChargeModels::Factory.new_instance( chargeable: charge, **options ).apply advance_model = ChargeModels::Factory.in_advance_charge_model_class(chargeable: charge) # Rails Way result = charge.calculate(**options) advance_calculator = charge.in_advance_calculator Collaborate with active_record-associated_object # " Gems are overrated 

app/services/badges/ ├── award.rb ├── award_beloved_comment.rb ├── award_community_wellness.rb ├── award_contributor.rb ├── award_contributor_from_github.rb ├── award_eight_week_streak.rb ├── award_fab_five.rb ├── award_first_post.rb ├── award_sixteen_week_streak.rb ├── award_streak.rb ├── award_tag.rb ├── award_thumbs_up.rb ├── award_top_seven.rb └── award_yearly_club.rb 

module Badges class AwardBelovedComment BADGE_SLUG = "beloved-comment".freeze def call return unless (badge_id = Badge.id_for_slug(BADGE_SLUG)) Comment.includes(:user).where(public_reactions_count: comment_count..).find_each do |comment| achievement = BadgeAchievement.create( user_id: comment.user_id, badge_id: badge_id, rewarding_context_message_markdown: generate_message(comment), ) comment.user.touch if achievement.valid? end end end end 

module Badges class AwardBelovedComment BADGE_SLUG = "beloved-comment".freeze def call return unless (badge_id = Badge.id_for_slug(BADGE_SLUG)) Comment.includes(:user).where(public_reactions_count: comment_count..).find_each do |comment| achievement = BadgeAchievement.create( user_id: comment.user_id, badge_id: badge_id, rewarding_context_message_markdown: generate_message(comment), ) comment.user.touch if achievement.valid? end end end end 1 

module Badges class AwardBelovedComment BADGE_SLUG = "beloved-comment".freeze def call return unless (badge_id = Badge.id_for_slug(BADGE_SLUG)) Comment.includes(:user).where(public_reactions_count: comment_count..).find_each do |comment| achievement = BadgeAchievement.create( user_id: comment.user_id, badge_id: badge_id, rewarding_context_message_markdown: generate_message(comment), ) comment.user.touch if achievement.valid? end end end end 1 2 

class BadgeAchievement < ApplicationRecord after_commit :bust_user_cache, on: %i[create destroy] # ... end module Badges class AwardBelovedComment BADGE_SLUG = "beloved-comment".freeze def call return unless (badge_id = Badge.id_for_slug(BADGE_SLUG)) Comment.includes(:user).where(public_reactions_count: comment_count..).find_each do |comment| achievement = BadgeAchievement.create( user_id: comment.user_id, badge_id: badge_id, rewarding_context_message_markdown: generate_message(comment), ) comment.user.touch if achievement.valid? end end end end 1 2 3 

class BadgeAchievement < ApplicationRecord after_commit :bust_user_cache, on: %i[create destroy] # ... end module Badges class AwardBelovedComment BADGE_SLUG = "beloved-comment".freeze def call return unless (badge_id = Badge.id_for_slug(BADGE_SLUG)) Comment.includes(:user).where(public_reactions_count: comment_count..).find_each do |comment| achievement = BadgeAchievement.create( user_id: comment.user_id, badge_id: badge_id, rewarding_context_message_markdown: generate_message(comment), ) comment.user.touch if achievement.valid? end end end end module Badges class AwardStreak def call badge_slug = "#{weeks}-week-streak" return unless (badge_id = Badge.id_for_slug(badge_slug)) users = User.where(id: article_user_ids).where("articles_count >= ?", weeks) users.find_each do |user| count = weeks.times.count { |i| published_x_weeks_ago?(user, i + 1) } next unless count >= weeks user.badge_achievements.create( badge_id: badge_id, rewarding_context_message_markdown: generate_message, ) end end end end 1 2 3 2 1 

module Badges class AwardStreak def call badge_slug = "#{weeks}-week-streak" return unless (badge_id = Badge.id_for_slug(badge_slug)) users = User.where(id: article_user_ids).where("articles_count >= ?", weeks) users.find_each do |user| count = weeks.times.count { |i| published_x_weeks_ago?(user, i + 1) } next unless count >= weeks user.badge_achievements.create( badge_id: badge_id, rewarding_context_message_markdown: generate_message, ) end end end end module Badges class AwardBelovedComment BADGE_SLUG = "beloved-comment".freeze def call return unless (badge_id = Badge.id_for_slug(BADGE_SLUG)) Comment.includes(:user).where(public_reactions_count: comment_count..).find_each do |comment| achievement = BadgeAchievement.create( user_id: comment.user_id, badge_id: badge_id, rewarding_context_message_markdown: generate_message(comment), ) comment.user.touch if achievement.valid? end end end end module Badges class AwardFabFive BADGE_SLUG = "fab-5".freeze def self.call(usernames, message_markdown = default_message_markdown) ::Badges::Award.call( User.where(username: usernames), BADGE_SLUG, message_markdown, ) end end class Award def self.call(user_relation, slug, message_markdown, include_default_description: true) return unless (badge_id = Badge.id_for_slug(slug)) user_relation.find_each do |user| achievement = user.badge_achievements.create( badge_id: badge_id, rewarding_context_message_markdown: message_markdown, include_default_description:, ) user.touch if achievement.persisted? end end end end class BadgeAwardWorker include Sidekiq::Job def perform(usernames, badge_slug, message, include_default_description = true) if (award_class = "Badges::#{badge_slug.classify}".safe_constantize) award_class.call else Badges::Award.call(User.where(username: usernames), badge_slug, message, include_default_description: ...) end end end 1 2 3 

app/models/badges/ ├── beloved_comment.rb ├── community_wellness.rb ├── contributor.rb ├── contributor_from_github.rb ├── fab_five.rb ├── first_post.rb ├── streak.rb # Streak.new(weeks: 4/8/16) ├── tag.rb ├── thumbs_up.rb ├── top_seven.rb └── yearly_club.rb app/services/badges/ └── grant.rb app/services/badges/ ├── award.rb ├── award_beloved_comment.rb ├── award_community_wellness.rb ├── award_contributor.rb ├── award_contributor_from_github.rb ├── award_eight_week_streak.rb ├── award_fab_five.rb ├── award_first_post.rb ├── award_sixteen_week_streak.rb ├── award_streak.rb ├── award_tag.rb ├── award_thumbs_up.rb ├── award_top_seven.rb └── award_yearly_club.rb 

app/models/badges/ ├── beloved_comment.rb ├── community_wellness.rb ├── contributor.rb ├── contributor_from_github.rb ├── fab_five.rb ├── first_post.rb ├── streak.rb # Streak.new(weeks: 4/8/16) ├── tag.rb ├── thumbs_up.rb ├── top_seven.rb └── yearly_club.rb app/services/badges/ └── grant.rb app/services/badges/ ├── award.rb ├── award_beloved_comment.rb ├── award_community_wellness.rb ├── award_contributor.rb ├── award_contributor_from_github.rb ├── award_eight_week_streak.rb ├── award_fab_five.rb ├── award_first_post.rb ├── award_sixteen_week_streak.rb ├── award_streak.rb ├── award_tag.rb ├── award_thumbs_up.rb ├── award_top_seven.rb └── award_yearly_club.rb 

class Badges::Streak def initialize(weeks:) = @weeks = weeks def slug = "#{@weeks}-week-streak" def qualifying_users ids = Article.published .where("published_at > ? AND score > ?", 1.week.ago, -25) .pluck(:user_id) User.where(id: ids).where("articles_count >= ?", @weeks) .select { |u| consecutive_weeks?(u) } end def message_for(_user) = I18n.t("...message", count: @weeks * 2) end 

class Badges::Streak def initialize(weeks:) = @weeks = weeks def slug = "#{@weeks}-week-streak" def qualifying_users ids = Article.published .where("published_at > ? AND score > ?", 1.week.ago, -25) .pluck(:user_id) User.where(id: ids).where("articles_count >= ?", @weeks) .select { |u| consecutive_weeks?(u) } end def message_for(_user) = I18n.t("...message", count: @weeks * 2) end class Badges::Grant def self.call(badge, users: nil, message: nil) return unless (badge_id = Badge.id_for_slug(badge.slug)) (users || badge.qualifying_users).find_each do |user| next if user.banished? user.badge_achievements.create( badge_id: badge_id, rewarding_context_message_markdown: message || badge.message_for(user), ) end end end 1 2 

DON'T NAME NOUNS AS VERBS Domain objects are not only Active Record models Stick to the Rails Way for as long as possible Think in objects first, functions/operations second If it quacks like a model it's a model 

EMERGING ABSTRACTIONS DROP CANDIDATES #5 

WHAT IF IT'S A SERVICE? Encapsulates a complex business operation Orchestrates multiple collaborators with side effects Communicates with external systems Not owned by a single model No junk, no sink, no disguise 

Emerging Notifications layer app/models/ └── notification.rb app/services/ ├── notifications.rb ├── notifications/ │ ├── new_comment/send.rb │ ├── new_follower/send.rb │ ├── new_follower/follow_data.rb │ ├── reactions/send.rb │ ├── reactions/reaction_data.rb │ ├── new_mention/send.rb │ ├── notifiable_action/send.rb │ ├── milestone/send.rb │ ├── moderation/send.rb │ ├── new_badge_achievement/send.rb │ ├── welcome_notification/send.rb │ ├── organization_deverification/send.rb │ ├── subforem_change_notification/send.rb │ ├── tag_adjustment_notification/send.rb │ ├── remove_all.rb │ ├── remove_all_by_action.rb │ ├── remove_by_spammer.rb │ └── update.rb └── push_notifications/send.rb app/workers/notifications/ ├── new_follower_worker.rb ├── new_reaction_worker.rb ├── mention_worker.rb ├── milestone_worker.rb ├── new_badge_achievement_worker.rb ├── notifiable_action_worker.rb ├── organization_deverification_worker.rb ├── subforem_change_notification_worker.rb ├── tag_adjustment_notification_worker.rb └── welcome_notification_worker.rb 

Emerging Notifications layer Events, delivery channels, management app/models/ └── notification.rb app/services/ ├── notifications.rb ├── notifications/ │ ├── new_comment/send.rb │ ├── new_follower/send.rb │ ├── new_follower/follow_data.rb │ ├── reactions/send.rb │ ├── reactions/reaction_data.rb │ ├── new_mention/send.rb │ ├── notifiable_action/send.rb │ ├── milestone/send.rb │ ├── moderation/send.rb │ ├── new_badge_achievement/send.rb │ ├── welcome_notification/send.rb │ ├── organization_deverification/send.rb │ ├── subforem_change_notification/send.rb │ ├── tag_adjustment_notification/send.rb │ ├── remove_all.rb │ ├── remove_all_by_action.rb │ ├── remove_by_spammer.rb │ └── update.rb └── push_notifications/send.rb app/workers/notifications/ ├── new_follower_worker.rb ├── new_reaction_worker.rb ├── mention_worker.rb ├── milestone_worker.rb ├── new_badge_achievement_worker.rb ├── notifiable_action_worker.rb ├── organization_deverification_worker.rb ├── subforem_change_notification_worker.rb ├── tag_adjustment_notification_worker.rb └── welcome_notification_worker.rb 

Emerging Notifications layer Events, delivery channels, management (Anemic) workers app/models/ └── notification.rb app/services/ ├── notifications.rb ├── notifications/ │ ├── new_comment/send.rb │ ├── new_follower/send.rb │ ├── new_follower/follow_data.rb │ ├── reactions/send.rb │ ├── reactions/reaction_data.rb │ ├── new_mention/send.rb │ ├── notifiable_action/send.rb │ ├── milestone/send.rb │ ├── moderation/send.rb │ ├── new_badge_achievement/send.rb │ ├── welcome_notification/send.rb │ ├── organization_deverification/send.rb │ ├── subforem_change_notification/send.rb │ ├── tag_adjustment_notification/send.rb │ ├── remove_all.rb │ ├── remove_all_by_action.rb │ ├── remove_by_spammer.rb │ └── update.rb └── push_notifications/send.rb app/workers/notifications/ ├── new_follower_worker.rb ├── new_reaction_worker.rb ├── mention_worker.rb ├── milestone_worker.rb ├── new_badge_achievement_worker.rb ├── notifiable_action_worker.rb ├── organization_deverification_worker.rb ├── subforem_change_notification_worker.rb ├── tag_adjustment_notification_worker.rb └── welcome_notification_worker.rb module Notifications class NewFollowerWorker include Sidekiq::Job def perform(follow_data) Notifications::NewFollower::Send.call(follow_data) end end end 

Emerging Notifications layer Events, delivery channels, management (Anemic) workers (Bloated) model app/models/ └── notification.rb app/services/ ├── notifications.rb ├── notifications/ │ ├── new_comment/send.rb │ ├── new_follower/send.rb │ ├── new_follower/follow_data.rb │ ├── reactions/send.rb │ ├── reactions/reaction_data.rb │ ├── new_mention/send.rb │ ├── notifiable_action/send.rb │ ├── milestone/send.rb │ ├── moderation/send.rb │ ├── new_badge_achievement/send.rb │ ├── welcome_notification/send.rb │ ├── organization_deverification/send.rb │ ├── subforem_change_notification/send.rb │ ├── tag_adjustment_notification/send.rb │ ├── remove_all.rb │ ├── remove_all_by_action.rb │ ├── remove_by_spammer.rb │ └── update.rb └── push_notifications/send.rb app/workers/notifications/ ├── new_follower_worker.rb ├── new_reaction_worker.rb ├── mention_worker.rb ├── milestone_worker.rb ├── new_badge_achievement_worker.rb ├── notifiable_action_worker.rb ├── organization_deverification_worker.rb ├── subforem_change_notification_worker.rb ├── tag_adjustment_notification_worker.rb └── welcome_notification_worker.rb class Notification < ApplicationRecord # ... class << self def send_new_follower_notification(follow) def send_new_follower_notification_without_delay(follow) def send_to_mentioned_users_and_followers(notifiable) def send_to_followers(notifiable, action = nil) def send_new_comment_notifications_without_delay(comment) def send_new_badge_achievement_notification(badge_achievement) def send_reaction_notification(reaction, rcvr) def send_reaction_notification_without_delay(reaction, rcvr) # ~10 more send_whatever methods end end 

Emerging Notifications layer Events, delivery channels, management (Anemic) workers (Bloated) model Payload generation app/models/ └── notification.rb app/services/ ├── notifications.rb ├── notifications/ │ ├── new_comment/send.rb │ ├── new_follower/send.rb │ ├── new_follower/follow_data.rb │ ├── reactions/send.rb │ ├── reactions/reaction_data.rb │ ├── new_mention/send.rb │ ├── notifiable_action/send.rb │ ├── milestone/send.rb │ ├── moderation/send.rb │ ├── new_badge_achievement/send.rb │ ├── welcome_notification/send.rb │ ├── organization_deverification/send.rb │ ├── subforem_change_notification/send.rb │ ├── tag_adjustment_notification/send.rb │ ├── remove_all.rb │ ├── remove_all_by_action.rb │ ├── remove_by_spammer.rb │ └── update.rb └── push_notifications/send.rb app/workers/notifications/ ├── new_follower_worker.rb ├── new_reaction_worker.rb ├── mention_worker.rb ├── milestone_worker.rb ├── new_badge_achievement_worker.rb ├── notifiable_action_worker.rb ├── organization_deverification_worker.rb ├── subforem_change_notification_worker.rb ├── tag_adjustment_notification_worker.rb └── welcome_notification_worker.rb module Notifications def self.user_data(user) { id: user.id, name: user.name, username: user.username, profile_image_90: user.profile_image_90, comments_count: user.comments_count } end def self.comment_data(comment) = { ... } def self.article_data(article) = { ... } def self.organization_data(organization) = { ... } end 

⚠ Logic spread across many files/layers ⚠ No clear convention ⚠ Tons of boilerplate app/models/ └── notification.rb app/services/ ├── notifications.rb ├── notifications/ │ ├── new_comment/send.rb │ ├── new_follower/send.rb │ ├── new_follower/follow_data.rb │ ├── reactions/send.rb │ ├── reactions/reaction_data.rb │ ├── new_mention/send.rb │ ├── notifiable_action/send.rb │ ├── milestone/send.rb │ ├── moderation/send.rb │ ├── new_badge_achievement/send.rb │ ├── welcome_notification/send.rb │ ├── organization_deverification/send.rb │ ├── subforem_change_notification/send.rb │ ├── tag_adjustment_notification/send.rb │ ├── remove_all.rb │ ├── remove_all_by_action.rb │ ├── remove_by_spammer.rb │ └── update.rb └── push_notifications/send.rb app/workers/notifications/ ├── new_follower_worker.rb ├── new_reaction_worker.rb ├── mention_worker.rb ├── milestone_worker.rb ├── new_badge_achievement_worker.rb ├── notifiable_action_worker.rb ├── organization_deverification_worker.rb ├── subforem_change_notification_worker.rb ├── tag_adjustment_notification_worker.rb └── welcome_notification_worker.rb 

app/notifiers/ ├── application_notifier.rb # #deliver, #deliver_later, etc ├── new_comment_notifier.rb ├── new_follower_notifier.rb ├── reaction_notifier.rb ├── new_mention_notifier.rb ├── article_published_notifier.rb ├── milestone_notifier.rb ├── moderation_notifier.rb ├── new_badge_achievement_notifier.rb ├── welcome_notifier.rb ├── organization_deverification_notifier.rb ├── subforem_change_notifier.rb └── tag_adjustment_notifier.rb app/models/concerns/notification/ └── maintenance.rb # remove_all, remove_all_by_action, etc app/workers/ └── notification_worker.rb lib/push_notifications/ └── sender.rb app/models/ └── notification.rb app/services/ ├── notifications.rb ├── notifications/ │ ├── new_comment/send.rb │ ├── new_follower/send.rb │ ├── new_follower/follow_data.rb │ ├── reactions/send.rb │ ├── reactions/reaction_data.rb │ ├── new_mention/send.rb │ ├── notifiable_action/send.rb │ ├── milestone/send.rb │ ├── moderation/send.rb │ ├── new_badge_achievement/send.rb │ ├── welcome_notification/send.rb │ ├── organization_deverification/send.rb │ ├── subforem_change_notification/send.rb │ ├── tag_adjustment_notification/send.rb │ ├── remove_all.rb │ ├── remove_all_by_action.rb │ ├── remove_by_spammer.rb │ └── update.rb └── push_notifications/send.rb app/workers/notifications/ ├── new_follower_worker.rb ├── new_reaction_worker.rb ├── mention_worker.rb ├── milestone_worker.rb ├── new_badge_achievement_worker.rb ├── notifiable_action_worker.rb ├── organization_deverification_worker.rb ├── subforem_change_notification_worker.rb ├── tag_adjustment_notification_worker.rb └── welcome_notification_worker.rb 

app/notifiers/ ├── application_notifier.rb # #deliver, #deliver_later, etc ├── new_comment_notifier.rb ├── new_follower_notifier.rb ├── reaction_notifier.rb ├── new_mention_notifier.rb ├── article_published_notifier.rb ├── milestone_notifier.rb ├── moderation_notifier.rb ├── new_badge_achievement_notifier.rb ├── welcome_notifier.rb ├── organization_deverification_notifier.rb ├── subforem_change_notifier.rb └── tag_adjustment_notifier.rb app/models/concerns/notification/ └── maintenance.rb # remove_all, remove_all_by_action, etc app/workers/ └── notification_worker.rb lib/push_notifications/ └── sender.rb app/models/ └── notification.rb app/services/ ├── notifications.rb ├── notifications/ │ ├── new_comment/send.rb │ ├── new_follower/send.rb │ ├── new_follower/follow_data.rb │ ├── reactions/send.rb │ ├── reactions/reaction_data.rb │ ├── new_mention/send.rb │ ├── notifiable_action/send.rb │ ├── milestone/send.rb │ ├── moderation/send.rb │ ├── new_badge_achievement/send.rb │ ├── welcome_notification/send.rb │ ├── organization_deverification/send.rb │ ├── subforem_change_notification/send.rb │ ├── tag_adjustment_notification/send.rb │ ├── remove_all.rb │ ├── remove_all_by_action.rb │ ├── remove_by_spammer.rb │ └── update.rb └── push_notifications/send.rb app/workers/notifications/ ├── new_follower_worker.rb ├── new_reaction_worker.rb ├── mention_worker.rb ├── milestone_worker.rb ├── new_badge_achievement_worker.rb ├── notifiable_action_worker.rb ├── organization_deverification_worker.rb ├── subforem_change_notification_worker.rb ├── tag_adjustment_notification_worker.rb └── welcome_notification_worker.rb 

app/notifiers/ ├── application_notifier.rb # #deliver, #deliver_later, etc ├── new_comment_notifier.rb ├── new_follower_notifier.rb ├── reaction_notifier.rb ├── new_mention_notifier.rb ├── article_published_notifier.rb ├── milestone_notifier.rb ├── moderation_notifier.rb ├── new_badge_achievement_notifier.rb ├── welcome_notifier.rb ├── organization_deverification_notifier.rb ├── subforem_change_notifier.rb └── tag_adjustment_notifier.rb app/models/concerns/notification/ └── maintenance.rb # remove_all, remove_all_by_action, etc app/workers/ └── notification_worker.rb lib/push_notifications/ └── sender.rb 

app/notifiers/ ├── application_notifier.rb # #deliver, #deliver_later, etc ├── new_comment_notifier.rb ├── new_follower_notifier.rb ├── reaction_notifier.rb ├── new_mention_notifier.rb ├── article_published_notifier.rb ├── milestone_notifier.rb ├── moderation_notifier.rb ├── new_badge_achievement_notifier.rb ├── welcome_notifier.rb ├── organization_deverification_notifier.rb ├── subforem_change_notifier.rb └── tag_adjustment_notifier.rb app/models/concerns/notification/ └── maintenance.rb # remove_all, remove_all_by_action, etc app/workers/ └── notification_worker.rb lib/push_notifications/ └── sender.rb class NewCommentNotifier < ApplicationNotifier channels :database, :push before_delivery do throw :abort if blocking?( commentable.user_id, comment.user_id ) end def recipients # scope or inline query end def notification_data # serializer or inline Hash end end NewCommentNotifier.new(comment).deliver_later 

app/notifiers/ ├── application_notifier.rb # #deliver, #deliver_later, etc ├── new_comment_notifier.rb ├── new_follower_notifier.rb ├── reaction_notifier.rb ├── new_mention_notifier.rb ├── article_published_notifier.rb ├── milestone_notifier.rb ├── moderation_notifier.rb ├── new_badge_achievement_notifier.rb ├── welcome_notifier.rb ├── organization_deverification_notifier.rb ├── subforem_change_notifier.rb └── tag_adjustment_notifier.rb app/models/concerns/notification/ └── maintenance.rb # remove_all, remove_all_by_action, etc app/workers/ └── notification_worker.rb lib/push_notifications/ └── sender.rb class NewCommentNotifier < ApplicationNotifier channels :database, :push before_delivery do throw :abort if blocking?( commentable.user_id, comment.user_id ) end def recipients # scope or inline query end def notification_data # serializer or inline Hash end end NewCommentNotifier.new(comment).deliver_later Have you Noticed...? 

MORE THAN A SERVICE Form and query objects Notifications (events, delivery channels) Authorization (policies, etc.) AI agents API clients and Webhook handlers Common service specializations in Rails apps 

MORE THAN A SERVICE Form and query objects Notifications (events, delivery channels) Authorization (policies, etc.) AI agents API clients and Webhook handlers Common service specializations in Rails apps You can do better with RubyLLM 

DON'T IGNORE YOUR CODE Identify and extract specialization clusters Give a cluster a name and recognizable shape, not just a place (a folder) and a generic contract Don't overpromote, keep under app/services, namespaced It's telling you what it wants to become 

DON'T IGNORE YOUR CODE Identify and extract specialization clusters Give a cluster a name and recognizable shape, not just a place (a folder) and a generic contract Don't overpromote, keep under app/services, namespaced It's telling you what it wants to become Abstract=extracted from a larger work 

SERVICES DONE RIGHT KEEP CANDIDATES #1 

ПРИКАЗКА ЗА БЪЧВАТА Wisdom older than software 

ПРИКАЗКА ЗА БЪЧВАТА Your code is the barrel Wisdom older than software 

ПРИКАЗКА ЗА БЪЧВАТА Your code is the barrel The wooden planks are the abstractions Wisdom older than software 

ПРИКАЗКА ЗА БЪЧВАТА Your code is the barrel The wooden planks are the abstractions The hoops are the conventions Wisdom older than software 

ПРИКАЗКА ЗА БЪЧВАТА Your code is the barrel The wooden planks are the abstractions The hoops are the conventions The wine is the developer happiness of working with maintainable code Wisdom older than software 

Outgoing Webhooks (sub-) layer Custom base class and API Test utils (shared examples and the context) ⚠ Still the same #call and -Service app/services/webhooks ├── base_service.rb ├── credit_notes │ ├── created_service.rb │ ├── generated_service.rb ├── customers │ ├── created_service.rb │ ├── updated_service.rb │ └── vies_check_service.rb ├── features │ ├── created_service.rb │ ├── deleted_service.rb │ └── updated_service.rb ├── fees │ └── pay_in_advance_created_service.rb ├── integrations ├── ... └── wallets ├── created_service.rb ├── depleted_ongoing_balance_service.rb ├── terminated_service.rb └── updated_service.rb spec/support ├── shared_contexts │ └── webhook_tracking.rb └── shared_examples └── creates_webhook.rb 

SERVICE OBJECTS FRAMEWORK class Chat::TrashMessage include Service::Base params do attribute :message_id, :integer attribute :channel_id, :integer validates :message_id, presence: true validates :channel_id, presence: true end model :message policy :invalid_access model :pinned_message, optional: true transaction do step :trash_message step :destroy_pin step :destroy_notifications step :update_thread_reply_cache end step :publish_events end 

SERVICE OBJECTS FRAMEWORK class Chat::TrashMessage include Service::Base params do attribute :message_id, :integer attribute :channel_id, :integer validates :message_id, presence: true validates :channel_id, presence: true end model :message policy :invalid_access model :pinned_message, optional: true transaction do step :trash_message step :destroy_pin step :destroy_notifications step :update_thread_reply_cache end step :publish_events end # controller def destroy Chat::TrashMessage.call(service_params) do on_success { render(json: success_json) } on_model_not_found(:message) { raise Discourse::NotFound } on_failed_policy(:invalid_access) { raise Discourse::InvalidAccess } on_failed_contract { |contract| render_error(contract.errors) } end end # specs context "when params are not valid" do it { is_expected.to fail_a_contract } end context "when the user has permission" do it { is_expected.to run_successfully } it "trashes the message" end 

SERVICE OBJECTS FRAMEWORK class Chat::TrashMessage include Service::Base params do attribute :message_id, :integer attribute :channel_id, :integer validates :message_id, presence: true validates :channel_id, presence: true end model :message policy :invalid_access model :pinned_message, optional: true transaction do step :trash_message step :destroy_pin step :destroy_notifications step :update_thread_reply_cache end step :publish_events end # controller def destroy Chat::TrashMessage.call(service_params) do on_success { render(json: success_json) } on_model_not_found(:message) { raise Discourse::NotFound } on_failed_policy(:invalid_access) { raise Discourse::InvalidAccess } on_failed_contract { |contract| render_error(contract.errors) } end end # specs context "when params are not valid" do it { is_expected.to fail_a_contract } end context "when the user has permission" do it { is_expected.to run_successfully } it "trashes the message" end Smells like Trailblazer::Operation 

SERVICE OBJECTS FRAMEWORK class Chat::TrashMessage include Service::Base params do attribute :message_id, :integer attribute :channel_id, :integer validates :message_id, presence: true validates :channel_id, presence: true end model :message policy :invalid_access model :pinned_message, optional: true transaction do step :trash_message step :destroy_pin step :destroy_notifications step :update_thread_reply_cache end step :publish_events end --- name: discourse-service-authoring description: Use when creating, editing, or reviewing Discourse service objects that include Service::Base --- ## Phase 4: Quality Review the service against these structural rules. List every violation found. - Service name describes the core business concept; namespace freely - Steps are simple with one concern each - Step names describe domain behavior, not code (revoke_previous_accepted_answer not destroy_old_record) - transaction wraps ONLY DB writes. Side effects live outside. - No return if/return unless at the top of step methods — use only_if wrappers - NEVER have utility methods in a service, use model, step or a dedicated action instead - Instead of manipulating data from the contract directly in various steps, extract logic on the contract itself - Each side effect is its own step with its own only_if wrapper — never bundle conditional side effects - No over-protection with try — trust internal bang methods - Mutation steps ordered so rollback leaves consistent state ... Version 2026 

SERVICES IN THE AI ERA How to unteach LLMs generating faceless services 

LLMS ❤ SERVICE OBJECTS AI learned "best practices" from us 

LLMS ❤ SERVICE OBJECTS AI is an amplifier: garbage in, garbage out AI learned "best practices" from us 

LLMS ❤ SERVICE OBJECTS AI is an amplifier: garbage in, garbage out It consumed a lot of "slim controllers, slim models, fat services" stuff during training AI learned "best practices" from us 

LLMS ❤ SERVICE OBJECTS AI is an amplifier: garbage in, garbage out It consumed a lot of "slim controllers, slim models, fat services" stuff during training Harness is required to generate undroppable app/services AI learned "best practices" from us 

SKILLS vs SERVICES github.com/palkan/skills ▐▛███▜▌ Клод Код v16.05.2026 ▝▜█████▛▘ Vovas 3.7 (1M context) · Claude Max ▘▘ ▝▝ > /layered-rails:analyze-services ✽ Hannabarbering… 

SKILLS vs SERVICES github.com/palkan/skills ▐▛███▜▌ Клод Код v16.05.2026 ▝▜█████▛▘ Vovas 3.7 (1M context) · Claude Max ▘▘ ▝▝ > Service Object Analysis — Mastodon TL;DR Extract a reusable ActivityPub distribution abstraction — a recording_activity service + controller helper — the single highest-leverage move; closes the presentation-layer leak in BaseService and dissolves a cluster of thin-wrapper services whose only value-add is federation boilerplate. In this project, a Service Object is … A class inheriting BaseService that wraps a single federated domain operation — typically an account relationship action or content mutation — exposing a uniform #call entry point that takes domain objects as positional arguments and an options hash, performs the mutation, then distributes ActivityPub payloads and enqueues workers for side effects. /layered-rails:analyze-services 

DROP YOUR app/services Having proper app/services is fine But there's a high chance that your waiting room is overcrowded Specialized abstractions are likely to exist in your codebase. Find and promote them! And populate it from scratch (if needed) 

CREDITS 

THANK YOU x.com/palkan_tula x.com/evilmartians