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>
```
Uppy V2 includes the S3 multipart batch presigning change
we contributed in d613b849a6
so we need to upgrade it. This also brings both package.json
files into line and accounts for the renaming of Plugin
to BasePlugin in Uppy.
This has been tested and is working locally for both
regular Ember and Ember CLI, for uploads.json
XHR uploads and for direct S3 uploads (single and multipart).
This mixin needs to be shared between the composer and composer-like
user interfaces. This commit makes it so the events and the underlying
data model is configurable by the component extending the ComposerUploadUppy
mixin.
Also removes two MessageBus unsubscribe calls which were unnecessary.
The generate_presigned_put endpoint for direct external uploads
(such as the one for the uppy-image-uploader) records allowed
S3 metadata values on the uploaded object. We use this to store
the sha1-checksum generated by the UppyChecksum plugin, for later
comparison in ExternalUploadManager.
However, we were not doing this for the create_multipart endpoint,
so the checksum was never captured and compared correctly.
Also includes a fix to make sure UppyChecksum is the last preprocessor to run.
It is important that the UppyChecksum preprocessor is the last one to
be added; the preprocessors are run in order and since other preprocessors
may modify the file (e.g. the UppyMediaOptimization one), we need to
checksum once we are sure the file data has "settled".
The user-topic-list template is also in use in other places when we want to improve blank page syndrome, so this PR is a preparation for that changes as well.
- uses tagName=""
- removes user property which is not being used
- extract utility functions
- better wording for boolean properties
- initializes all properties
- uses @action
- uses optional chaining
- other minor changes
This rolls uppy back to the previous bundle that was used,
which will break multipart functionality (which is not yet
enabled anywhere).
No other upload functionality should be affected by this change,
it will be as if d295a16dab had
not been merged.
Users can invite people to topic and they will be automatically
redirected to the topic when logging in after signing up. This commit
ensures a "invited_to_topic" notification is created when the invite is
redeemed.
The same notification is used for the "Notify" sharing method that is
found in share topic modal.
This bug was introduced by f66007ec83.
In PostJobsEnqueuer we previously did not fire the after_post_create
event and after_topic_create event for private message topics. This was
changed in the above commit in order to publish message bus messages
for topic tracking state updates. Unfortunately this caused the
NotifyMailingListSubscribers job to be enqueued for all posts including
private messages, and admins and the users involved in the PMs got
emailed the contents of the PMs if they had mailing list mode enabled.
Luckily the impact of this was mitigated by a Guardian#can_see? check
for each mailing list mode user in the NotifyMailingListSubscribers job.
We never want to notify mailing list mode subscribers for private messages
so an early return has been added there, plus the logic in PostJobsEnqueuer
has been fixed, and tests have been added to that class where there were
none before.
Since ad3ec5809f when a user chooses
the Dismiss New... option in the New topic list, we send a request
to topics/reset-new.json with ?tracked=false as the only parameter.
This then uses Topic as the scope for topics to dismiss, with no
other limitations. When we do topic_scope.pluck(:id), it gets the
ID of every single topic in the database (that is not deleted) to
pass to TopicsBulkAction, causing a huge query with severe performance
issues.
This commit changes the default scope to use
`TopicQuery.new(current_user).new_results(limit: false)`
which should only use the topics in the user's New list, which
will be a much smaller list, depending on the user's "new_topic_duration_minutes"
setting.
This is unnecessary, as when the temporary key is created
in S3Store we already include the s3_bucket_folder_path, and
the key will always start with temp/ to assist with lifecycle
rules for multipart uploads.
This was affecting Discourse.store.object_from_path,
Discourse.store.signed_url_for_path, and possibly others.
See also: e0102a5
Whenever we `subscribe` to something there should be an equivalent
`unsubscribe` and this implements it for `LogsNotice`.
In the future we should make this closer to what Ember expects a Service
to be, but at least it's properly cleaning up after itself now.
This can be used to change the list of topic posters. For example,
discourse-solved can use this to move the user who posted the solution
after the original poster.
See the previous commit d66b258b0e as
well.
If enable_upload_debug_mode is true, we do not want to abort the
direct S3 upload, because that will delete the file on S3 and prevent
further inspection of any errors that have come up.
There are certain design decisions that were made in this commit.
Private messages implements its own version of topic tracking state because there are significant differences between regular and private_message topics. Regular topics have to track categories and tags while private messages do not. It is much easier to design the new topic tracking state if we maintain two different classes, instead of trying to mash this two worlds together.
One MessageBus channel per user and one MessageBus channel per group. This allows each user and each group to have their own channel backlog instead of having one global channel which requires the client to filter away unrelated messages.
