aprs.me/lib/aprsme/postgres_notifier.ex

69 lines
2.3 KiB
Elixir

defmodule Aprsme.PostgresNotifier do
@moduledoc """
Listens to PostgreSQL NOTIFY events on the "aprs_events" and "aprs_packets" channels and broadcasts
them via Phoenix.PubSub for reactive, event-driven updates.
"""
use GenServer
@event_channel "aprs_events"
@event_topic "postgres:aprsme_events"
@packet_channel "aprs_packets"
@packet_topic "postgres:aprsme_packets"
def start_link(_opts) do
GenServer.start_link(__MODULE__, nil, name: __MODULE__)
end
@impl true
def init(_) do
{:ok, conn} = Postgrex.Notifications.start_link(Aprsme.Repo.config())
{:ok, _ref1} = Postgrex.Notifications.listen(conn, @event_channel)
{:ok, _ref2} = Postgrex.Notifications.listen(conn, @packet_channel)
{:ok, %{conn: conn}}
end
@impl true
def handle_info({:notification, _conn, _pid, @event_channel, payload}, state) do
Phoenix.PubSub.broadcast(Aprsme.PubSub, @event_topic, {:postgres_notify, payload})
{:noreply, state}
end
def handle_info({:notification, _conn, _pid, @packet_channel, payload}, state) do
case Jason.decode(payload) do
{:ok, packet} ->
# Broadcast to the general packet topic
Phoenix.PubSub.broadcast(Aprsme.PubSub, @packet_topic, {:postgres_packet, packet})
# Also broadcast to callsign-specific weather topic if it's a weather packet
broadcast_weather_packet_if_relevant(packet)
_ ->
:noop
end
{:noreply, state}
end
def handle_info(_msg, state), do: {:noreply, state}
defp broadcast_weather_packet_if_relevant(packet) do
# Check if this is a weather packet using centralized weather fields
has_weather_data =
Enum.any?(Aprsme.EncodingUtils.weather_fields(), fn field ->
value = Map.get(packet, to_string(field))
not is_nil(value)
end)
if has_weather_data do
# Extract callsign from packet
callsign = Map.get(packet, "sender") || Map.get(packet, :sender)
if is_binary(callsign) and callsign != "" do
# Normalize callsign and broadcast to weather-specific topic
normalized_callsign = String.upcase(String.trim(callsign))
weather_topic = "weather:#{normalized_callsign}"
Phoenix.PubSub.broadcast(Aprsme.PubSub, weather_topic, {:weather_packet, packet})
end
end
end
end