discourse/documentation/chat/frontend/module.exports.html
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

198 lines
6.3 KiB
HTML

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Discourse: exports</title>
<link type="text/css" rel="stylesheet" href="styles/vendor/prism-custom.css">
<link type="text/css" rel="stylesheet" href="styles/styles.css">
</head>
<body>
<header class="layout-header">
<h1>
<a href="./index.html">
Discourse
</a>
</h1>
<nav class="layout-nav">
<ul><li class="nav-heading">Classes</li><li class="nav-heading"><span class="nav-item-type type-class" title="class">C</span><span class="nav-item-name is-class"><a href="PluginApi.html">PluginApi</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="PluginApi.html#decorateChatMessage">decorateChatMessage</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="PluginApi.html#registerChatComposerButton">registerChatComposerButton</a></span></li><li class="nav-heading"><span class="nav-item-type type-class" title="class">C</span><span class="nav-item-name is-class"><a href="module.exports.html">exports</a></span></li></ul><ul><li class="nav-heading">Modules</li><li class="nav-heading"><span class="nav-item-type type-module" title="module">M</span><span class="nav-item-name is-module"><a href="module-ChatApi.html">ChatApi</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#categoryPermissions">categoryPermissions</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#channel">channel</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#channels">channels</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#createChannel">createChannel</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#createChannelArchive">createChannelArchive</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#destroyChannel">destroyChannel</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#followChannel">followChannel</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#listChannelMemberships">listChannelMemberships</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#listCurrentUserChannels">listCurrentUserChannels</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#moveChannelMessages">moveChannelMessages</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#sendMessage">sendMessage</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#unfollowChannel">unfollowChannel</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#updateChannel">updateChannel</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#updateChannelStatus">updateChannelStatus</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="module-ChatApi.html#updateCurrentUserChannelNotificationsSettings">updateCurrentUserChannelNotificationsSettings</a></span></li></ul><li class="nav-heading"><a href="global.html">Globals</a></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="global.html#load">load</a></span></li><li class="nav-item"><span class="nav-item-type type-function" title="function">F</span><span class="nav-item-name is-function"><a href="global.html#loadMore">loadMore</a></span></li>
</nav>
</header>
<main class="layout-main ">
<div class="container">
<p class="page-kind">Class</p>
<h1 class="page-title">exports</h1>
<section>
<header class="class">
<!-- <h2>exports</h2> -->
<div class="class-description">Handles a paginated API response.</div>
</header>
<article>
<div class="container-overview">
<h3 class="subtitle">Constructor</h3>
<div class="method-type">
</div>
<h4 class="method-name" id="exports">new exports<span class="signature">()</span><span class="return-type-signature"></span>
</h4>
<div class="details">
</div>
<h4 class="method-heading">Source</h4>
<ul>
<li class="method-source">
<a href="lib_collection.js.html">lib/collection.js</a><a href="lib_collection.js.html#source.9">, line 9</a>
</li>
</ul>
</div>
</article>
</section>
</div>
</main>
<footer class="layout-footer">
<div class="container">
Documentation generated by <a href="https://github.com/jsdoc3/jsdoc">JSDoc 4.0.0</a>
</div>
</footer>
<script src="scripts/prism.dev.js"></script>
</body>
</html>