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>'
```
Note this is a very large PR, and some of it could have been splited, but keeping it one chunk made it to merge conflicts and to revert if necessary. Actual new code logic is also not that much, as most of the changes are removing js tests, adding system specs or moving things around.
To make it possible this commit is doing the following changes:
- converting (and adding new) existing js acceptances tests into system tests. This change was necessary to ensure as little regressions as possible while changing paradigm
- moving away from store. Using glimmer and tracked properties requires to have class objects everywhere and as a result works well with models. However store/adapters are suffering from many bugs and limitations. As a workaround the `chat-api` and `chat-channels-manager` are an answer to this problem by encapsulating backend calls and frontend storage logic; while still using js models.
- dropping `appEvents` as much as possible. Using tracked properties and a better local storage of channel models, allows to be much more reactive and doesn’t require arbitrary manual updates everywhere in the app.
- while working on replacing store, the existing work of a chat api (backend) has been continued to support more cases.
- removing code from the `chat` service to separate concerns, `chat-subscriptions-manager` and `chat-channels-manager`, being the largest examples of where the code has been rewritten/moved.
Future wok:
- improve behavior when closing/deleting a channel, it's already slightly buggy on live, it's rare enough that it's not a big issue, but should be improved
- improve page objects used in chat
- move more endpoints to the API
- finish temporarily skipped tests
- extract more code from the `chat` service
- use glimmer for `chat-messages`
- separate concerns in `chat-live-pane`
- eventually add js tests for `chat-api`, `chat-channels-manager` and `chat-subscriptions-manager`, they are indirectly heavy tested through system tests but it would be nice to at least test the public API
<!-- NOTE: All pull requests should have tests (rspec in Ruby, qunit in JavaScript). If your code does not include test coverage, please include an explanation of why it was omitted. -->
Currently it’s not possible to delete a category if an associated chat
channel is present even if there are no messages in this channel.
This can lead to annoying situations for our users.
This patch addresses the issue by checking if the channel is empty
instead of just checking if there is a channel.
This is a followup of the previous refactor where we created two new
models to handle all the dedicated logic that was present in the
`ChatChannel` model.
For the sake of consistency, `DMChannel` has been renamed to
`DirectMessageChannel` and the previous `DirectMessageChannel` model is
now named `DirectMessage`. This should help reasoning about direct
messages.
Martin Brennan
David Taylor
Joffrey JAFFEUX
Loïc Guitaut
Roman Rizzi