/discourse-refcount-resource-spike

Primary LanguageJavaScript

discourse-refcount-resource-spike

This project demonstrates the usage of a refcounted tracking system to manage the lifetime of a resource based upon registered interest.

For a more complete ember addon that uses similar primitives to manage resources, see ember-resources.

Overview

This simple demo optionally shows the current user's avatar in a couple places on the home page. Visibility of each is controlled with a simple checkbox. When an avatar is visible, we want to ensure that its associated username stays up to date, so we subscribe to a mock UserStream "resource" to check for updates (it actually just sets a timer and updates the current user's username to @johndoe 0, @johndoe 1, etc. every second). Avatars will all share this single resource to stay in sync. And when the resource is no longer needed, it is automatically disconnected to reduce load on both the client and server.

In order to manage the lifetime of this resource, a refcounting system is used that binds each avatar's lifetime to its usage of the resource.

When an avatar is shown, the associated component will register its interest with the resource for the lifetime of the component. Internally, this will increment a refcount by one and start the polling process within UserStream.

As each additional avatar is shown, its associated component will also register its interest with the resource. Each registration will bump the shared refcount.

As each avatar is hidden, its associated component will be destroyed. Because these components have their lifetimes linked with resource, their destruction will automatically decrement the shared refcount.

Once this refcount reaches 0, the shared UserStream resource instance will be destroyed, which in turn will stop the polling.

Prerequisites

You will need the following things properly installed on your computer.

Installation

  • git clone <repository-url> this repository
  • cd discourse-refcount-resource-spike
  • pnpm install

Running / Development

Code Generators

Make use of the many generators for code, try ember help generate for more details

Running Tests

  • ember test
  • ember test --server

Linting

  • pnpm lint
  • pnpm lint:fix

Building

  • ember build (development)
  • ember build --environment production (production)

Deploying

Specify what it takes to deploy your app.

Further Reading / Useful Links