beryl/presence/wire

Phoenix-compatible wire encoding for presence diffs.

Functions

`encode_diff`

pub fn encode_diff(
  presence.Diff,
  String
) -> json.Json

Encode a presence diff for one topic as a Phoenix-compatible payload.

The resulting JSON has joins and leaves maps. Presence keys index the maps. Each value contains the tracked metadata under metas.

Encoding does not include the diff's delivery scope. Prefer beryl.broadcast_presence_diff for socket delivery; a custom publisher must honor presence.diff_scope before sending this payload to other nodes.

{
  "joins": { "user:1": { "metas": [{ "status": "online" }] } },
  "leaves": { "user:2": { "metas": [{ "status": "offline" }] } }
}

`encode_state`

pub fn encode_state(List(presence.PresenceEntry)) -> json.Json

Encode a topic's full presence list as a Phoenix-compatible presence_state payload.

The resulting JSON is a map indexed by presence key. Each value contains the tracked metadata under metas. This is the same shape as one side of a presence_diff:

{ "user:1": { "metas": [{ "status": "online", "phx_ref": "..." }] } }

Phoenix clients expect a presence_state event with this payload after they join a presence-enabled topic. Incremental presence_diff events follow it. Build the entry list with presence.list.