PresenceChannel aims to be a generic system for allow the server, and end-users, to track the number and identity of users performing a specific task on the site. For example, it might be used to track who is currently 'replying' to a specific topic, editing a specific wiki post, etc.
A few key pieces of information about the system:
- PresenceChannels are identified by a name of the format `/prefix/blah`, where `prefix` has been configured by some core/plugin implementation, and `blah` can be any string the implementation wants to use.
- Presence is a boolean thing - each user is either present, or not present. If a user has multiple clients 'present' in a channel, they will be deduplicated so that the user is only counted once
- Developers can configure the existence and configuration of channels 'just in time' using a callback. The result of this is cached for 2 minutes.
- Configuration of a channel can specify permissions in a similar way to MessageBus (public boolean, a list of allowed_user_ids, and a list of allowed_group_ids). A channel can also be placed in 'count_only' mode, where the identity of present users is not revealed to end-users.
- The backend implementation uses redis lua scripts, and is designed to scale well. In the future, hard limits may be introduced on the maximum number of users that can be present in a channel.
- Clients can enter/leave at will. If a client has not marked itself 'present' in the last 60 seconds, they will automatically 'leave' the channel. The JS implementation takes care of this regular check-in.
- On the client-side, PresenceChannel instances can be fetched from the `presence` ember service. Each PresenceChannel can be used entered/left/subscribed/unsubscribed, and the service will automatically deduplicate information before interacting with the server.
- When a client joins a PresenceChannel, the JS implementation will automatically make a GET request for the current channel state. To avoid this, the channel state can be serialized into one of your existing endpoints, and then passed to the `subscribe` method on the channel.
- The PresenceChannel JS object is an ember object. The `users` and `count` property can be used directly in ember templates, and in computed properties.
- It is important to make sure that you `unsubscribe()` and `leave()` any PresenceChannel objects after use
An example implementation may look something like this. On the server:
```ruby
register_presence_channel_prefix("site") do |channel|
next nil unless channel == "/site/online"
PresenceChannel::Config.new(public: true)
end
```
And on the client, a component could be implemented like this:
```javascript
import Component from "@ember/component";
import { inject as service } from "@ember/service";
export default Component.extend({
presence: service(),
init() {
this._super(...arguments);
this.set("presenceChannel", this.presence.getChannel("/site/online"));
},
didInsertElement() {
this.presenceChannel.enter();
this.presenceChannel.subscribe();
},
willDestroyElement() {
this.presenceChannel.leave();
this.presenceChannel.unsubscribe();
},
});
```
With this template:
```handlebars
Online: {{presenceChannel.count}}
<ul>
{{#each presenceChannel.users as |user|}}
<li>{{avatar user imageSize="tiny"}} {{user.username}}</li>
{{/each}}
</ul>
```
This allows plugins to call `register_demon_process` with a Class inheriting from Demon::Base. The unicorn master process will take care of spawning, monitoring and restarting the process. This API should be used with extreme caution, but it is significantly cleaner than spawning processes/threads in an `after_initialize` block.
This commit also cleans up the demon spawning logging so that it uses the same format as unicorn worker logging. It also switches to the block form of `fork` to ensure that Demons exit after running, rather than returning execution to where the fork took place.
* Added scopes UI
* Create scopes when creating a new API key
* Show scopes on the API key show route
* Apply scopes on API requests
* Extend scopes from plugins
* Add missing scopes. A mapping can be associated with multiple controller actions
* Only send scopes if the use global key option is disabled. Use the discourse plugin registry to add new scopes
* Add not null validations and index for api_key_id
* Annotate model
* DEV: Move default mappings to ApiKeyScope
* Remove unused attribute and improve UI for existing keys
* Support multiple parameters separated by a comma
This reverts commit 20780a1eee.
* SECURITY: re-adds accidentally reverted commit:
03d26cd6: ensure embed_url contains valid http(s) uri
* when the merge commit e62a85cf was reverted, git chose the 2660c2e2 parent to land on
instead of the 03d26cd6 parent (which contains security fixes)
* DEV: Add framework for filtered plugin registers
Plugins often need to add values to a list, and we need to filter those lists at runtime to ignore values from disabled plugins. This commit provides a re-usable way to do that, which should make it easier to add new registers in future, and also reduce repeated code.
Follow-up commits will migrate existing registers to use this new system
* DEV: Migrate user and group custom field APIs to plugin registry
This gives us a consistent system for checking plugin enabled state, so we are repeating less logic. API changes are backwards compatible
Use a helper method to simplify creating a new register. Previously this would require creating lots of different methods manually, and adding every register to the clear/reset functions
* Remove some `.es6` from comments where it does not matter
* Use a post processor for transpilation
This will allow us to eventually use the directory structure to
transpile rather than the extension.
* FIX: Some errors and clean up in confirm-new-email
It would throw an error if the webauthn element wasn't present.
Also I changed things so that no-module is not explicitly
referenced.
* Remove `no-module`
Instead we allow a magic comment: `// discourse-skip-module` to prevent
the asset pipeline from creating a module.
* DEV: Enable babel transpilation based on directory
If it's in `app/assets/javascripts/dicourse` it will be transpiled
even without the `.es6` extension.
* REFACTOR: Remove Tilt/ES6ModuleTranspiler
This reduces chances of errors where consumers of strings mutate inputs
and reduces memory usage of the app.
Test suite passes now, but there may be some stuff left, so we will run
a few sites on a branch prior to merging
* Add missing icons to set
* Revert FA5 revert
This reverts commit 42572ff
* use new SVG syntax in locales
* Noscript page changes (remove login button, center "powered by" footer text)
* Cast wider net for SVG icons in settings
- include any _icon setting for SVG registry (offers better support for plugin settings)
- let themes store multiple pipe-delimited icons in a setting
- also replaces broken onebox image icon with SVG reference in cooked post processor
* interpolate icons in locales
* Fix composer whisper icon alignment
* Add support for stacked icons
* SECURITY: enforce hostname to match discourse hostname
This ensures that the hostname rails uses for various helpers always matches
the Discourse hostname
* load SVG sprite with pre-initializers
* FIX: enable caching on SVG sprites
* PERF: use JSONP for SVG sprites so they are served from CDN
This avoids needing to deal with CORS for loading of the SVG
Note, added the svg- prefix to the filename so we can quickly tell in
dev tools what the file is
* Add missing SVG sprite JSONP script to CSP
* Upgrade to FA 5.5.0
* Add support for all FA4.7 icons
- adds complete frontend and backend for renamed FA4.7 icons
- improves performance of SvgSprite.bundle and SvgSprite.all_icons
* Fix group avatar flair preview
- adds an endpoint at /svg-sprites/search/:keyword
- adds frontend ajax call that pulls icon in avatar flair preview even when it is not in subset
* Remove FA 4.7 font files
* First take on subsetting svg icons
* FontAwesome 5 svg subset WIP
* Include icons from plugins/badges into svg sprite subset
* add svg icon support to themes
* Add spec for SvgSprite
* Misc. SVG icon fixes
* Use FA5 svgs in local-dates plugin
* CSS adjustments, fix SVG icons in group flair
* Use SVG icons in poll plugin
* Add SVG icons to /wizard
Krzysztof Kotlarek
David Taylor
Roman Rizzi
Mark VanLandingham
Penar Musaraj
Ahmed Gagan
Blake Erickson
Michael Brown
Jeff Atwood
Robin Ward
Vinoth Kannan
Sam Saffron
Joffrey JAFFEUX
Gerhard Schlager
Jeff Wong
Guo Xiang Tan
Régis Hanol