MSC4359: "Do not Disturb" notification settings

proposals/4359-do-not-disturb.md

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+# MSC4359: "Do not Disturb" notification settings
+
+"Do not Disturb" (DnD) is a common feature of notification settings on various chat platforms. It
+may act globally but also on a per-room or per-device basis and involves inhibiting prominent visual
+or audible notifications without stopping to track them. This makes it possible for users to consume
+these notifications later once DnD is disabled. It is important to differentiate DnD from "Muting"
+where notifications are lost entirely and cannot be picked up on later.
+
+In Matrix, notifications for new and unread content are configured via [push rules]. Push rules
+currently don't support DnD. Rules can either notify or not but the notification state is entangled
+with the unread state. This means push rules only support muting but not DnD.
+
+As evidenced in [MSC3768] extending the push rule system to support DnD isn't trivial. This
+proposal, therefore, takes a different approach by introducing an overlay configuration that allows
+controlling DnD separately from push rules.
+
+## Proposal
+
+A new global account data event `m.do_not_disturb` is introduced. Its `content` contains a single
+property `rooms` that is a mapping from room ID to empty object (for future extensibility).
+
+``` json5
+{
+  "type": "m.do_not_disturb",
+  "content": {
+    "rooms": {
+        "!foo:bar.baz" {}, // Don't notify about new content in this room
+        ...
+    }
+  }
+}
+```
+
+Instead of a valid room ID, `*` is also allowed and will match any room. Otherwise, globbing is not
+permitted.
+
+For any room matched by `m.do_not_disturb`, clients MUST suppress system-level notifications such as
+sounds or notification pop-ups. Clients SHOULD also render unread state and counters less
+prominently for matched rooms.
+
+`m.do_not_disturb` applies to all devices in a user's account. It MAY be overridden on a per-device
+basis using account data events of type `m.do_not_disturb.<DEVICE_ID>`.
+
+``` json5
+{
+  "type": "m.do_not_disturb.ABCDEFG",
+  "content": {
+    "rooms": {
+        "*" {}, // Don't notify at all on this device
+    }
+  }
+}
+```
+
+To avoid flooding account data with per-device configurations, home servers SHOULD delete any
+`m.do_not_disturb.<DEVICE_ID>` event when the given device is removed.
+
+## Potential issues
+
+This proposal creates another configuration system on top of push rules thereby complicating the
+overall system further.
+
+For clients that depend on remote notifications, the dispatch and delivery of these notifications is
+not paused when in DnD mode. This might waste a certain amount of resources on both servers and
+clients.
+
+## Alternatives
+
+[MSC3768] integrates DnD into the existing push rule system. This significantly increases the
+complexity of managing push rules, however.
+
+[MSC3881] allows clients to toggle pushers on and off without unregistering them. This makes it
+possible to pause the delivery of remote notifications but only works on clients that use pushers
+such as mobile apps. Additionally, it doesn't allow pausing notifications on a per-room level.
+
+[MSC3890] is similar to this proposal but explicitly excludes clients that rely on pushers. Similar
+to [MSC3881], it also doesn't work on a per-room level.
+
+Clients could also use custom local settings to store DnD configurations without any changes to the
+specification. This would require each client to invent its own system for storage and matching,
+however. Additionally, custom client settings would make it impossible to centrally control DnD for
+all devices at once.
+
+## Security considerations
+
+None.
+
+## Unstable prefix
+
+While this MSC is not considered stable, `m.do_not_disturb` should be referred to as
+`dm.filament.do_not_disturb`.
+
+## Dependencies
+
+None.
+
+  [push rules]: https://spec.matrix.org/v1.15/client-server-api/#push-rules
+  [MSC3768]: https://github.com/matrix-org/matrix-spec-proposals/pull/3768
+  [MSC3881]: https://github.com/matrix-org/matrix-spec-proposals/pull/3881
+  [MSC3890]: https://github.com/matrix-org/matrix-spec-proposals/pull/3890