discourse/plugins/chat/lib
Martin Brennan 60ad836313
DEV: Chat service object initial implementation (#19814)
This is a combined work of Martin Brennan, Loïc Guitaut, and Joffrey Jaffeux.

---

This commit implements a base service object when working in chat. The documentation is available at https://discourse.github.io/discourse/chat/backend/Chat/Service.html

Generating documentation has been made as part of this commit with a bigger goal in mind of generally making it easier to dive into the chat project.

Working with services generally involves 3 parts:

- The service object itself, which is a series of steps where few of them are specialized (model, transaction, policy)

```ruby
class UpdateAge
  include Chat::Service::Base

  model :user, :fetch_user
  policy :can_see_user
  contract
  step :update_age

  class Contract
    attribute :age, :integer
  end

  def fetch_user(user_id:, **)
    User.find_by(id: user_id)
  end

  def can_see_user(guardian:, **)
    guardian.can_see_user(user)
  end

  def update_age(age:, **)
    user.update!(age: age)
  end
end
```

- The `with_service` controller helper, handling success and failure of the service within a service and making easy to return proper response to it from the controller

```ruby
def update
  with_service(UpdateAge) do
    on_success { render_serialized(result.user, BasicUserSerializer, root: "user") }
  end
end
```

- Rspec matchers and steps inspector, improving the dev experience while creating specs for a service

```ruby
RSpec.describe(UpdateAge) do
  subject(:result) do
    described_class.call(guardian: guardian, user_id: user.id, age: age)
  end

  fab!(:user) { Fabricate(:user) }
  fab!(:current_user) { Fabricate(:admin) }

  let(:guardian) { Guardian.new(current_user) }
  let(:age) { 1 }

   it { expect(user.reload.age).to eq(age) }
end
```

Note in case of unexpected failure in your spec, the output will give all the relevant information:

```
  1) UpdateAge when no channel_id is given is expected to fail to find a model named 'user'
     Failure/Error: it { is_expected.to fail_to_find_a_model(:user) }

       Expected model 'foo' (key: 'result.model.user') was not found in the result object.

       [1/4] [model] 'user' 
       [2/4] [policy] 'can_see_user'
       [3/4] [contract] 'default'
       [4/4] [step] 'update_age'

       /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/update_age.rb:32:in `fetch_user': missing keyword: :user_id (ArgumentError)
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:202:in `instance_exec'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:202:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:219:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `block in run!'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `each'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:417:in `run!'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:411:in `run'
       	from <internal:kernel>:90:in `tap'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/app/services/base.rb:302:in `call'
       	from /Users/joffreyjaffeux/Code/pr-discourse/plugins/chat/spec/services/update_age_spec.rb:15:in `block (3 levels) in <main>'
```
2023-02-13 13:09:57 +01:00
..
discourse_dev
email_controller_helper
extensions DEV: makes test more deterministic (#20078) 2023-01-30 22:02:32 +01:00
onebox/templates DEV: /channel -> /c chat route rename (#19782) 2023-01-27 09:58:12 -03:00
tasks DEV: Chat service object initial implementation (#19814) 2023-02-13 13:09:57 +01:00
validators
chat_channel_archive_service.rb FIX: Use hashtags in channel archive PMs if available (#19859) 2023-01-16 10:20:37 +10:00
chat_channel_fetcher.rb DEV: Apply syntax_tree formatting to plugins/* 2023-01-07 11:11:37 +00:00
chat_channel_hashtag_data_source.rb DEV: Change HashtagAutocompleteService to use DiscoursePluginRegistry (#19491) 2022-12-19 13:46:17 +10:00
chat_channel_membership_manager.rb
chat_mailer.rb DEV: Apply syntax_tree formatting to plugins/* 2023-01-07 11:11:37 +00:00
chat_message_bookmarkable.rb FIX: access to category chat only when user can create post (#19488) 2022-12-19 11:35:28 +11:00
chat_message_creator.rb FEATURE: Automatically create chat threads in background (#20206) 2023-02-08 10:22:07 +10:00
chat_message_processor.rb FIX: Add missing user_id args for ChatMessage.cook (#19508) 2022-12-19 11:05:37 +10:00
chat_message_rate_limiter.rb
chat_message_reactor.rb DEV: start glimmer-ification and optimisations of chat plugin (#19531) 2022-12-21 13:21:02 +01:00
chat_message_updater.rb DEV: Use UploadReference instead of ChatUpload in chat (#19947) 2023-01-24 13:28:21 +10:00
chat_notifier.rb DEV: Apply syntax_tree formatting to plugins/* 2023-01-07 11:11:37 +00:00
chat_review_queue.rb
chat_seeder.rb
chat_statistics.rb
chat_transcript_service.rb DEV: Use UploadReference instead of ChatUpload in chat (#19947) 2023-01-24 13:28:21 +10:00
direct_message_channel_creator.rb FEATURE: introduces chat_max_direct_message_users setting (#18997) 2022-11-15 10:40:28 +01:00
duplicate_message_validator.rb DEV: Apply syntax_tree formatting to plugins/* 2023-01-07 11:11:37 +00:00
endpoint.rb DEV: Chat service object initial implementation (#19814) 2023-02-13 13:09:57 +01:00
guardian_extensions.rb DEV: Chat service object initial implementation (#19814) 2023-02-13 13:09:57 +01:00
message_mover.rb FEATURE: Automatically create chat threads in background (#20206) 2023-02-08 10:22:07 +10:00
post_notification_handler.rb
secure_uploads_compatibility.rb
slack_compatibility.rb
steps_inspector.rb DEV: Chat service object initial implementation (#19814) 2023-02-13 13:09:57 +01:00