implement fetch callback to list users

lib/live_beats/accounts.ex

@@ -21,8 +21,8 @@ defmodule LiveBeats.Accounts do
     Repo.all(from u in User, limit: ^Keyword.fetch!(opts, :limit))
   end
 
-  def list_users_by_ids(user_ids) when is_list(user_ids) do
-    Repo.all(from u in User, where: u.id in ^user_ids)
+  def get_users_map(user_ids) when is_list(user_ids) do
+    Repo.all(from u in User, where: u.id in ^user_ids, select: {u.id, u})
   end
 
   def lists_users_by_active_profile(id, opts) do

lib/live_beats/presence/phoenix_presence_client.ex

@@ -177,8 +177,6 @@ defmodule Phoenix.Presence.Client do
   end
 
   defp topic_presences_count(state, topic) do
-    state.topics[topic]
-    |> Map.keys()
-    |> Enum.count()
+    map_size(state.topics[topic])
   end
 end

lib/live_beats_web/channels/presence.ex

@@ -12,6 +12,8 @@ defmodule LiveBeatsWeb.Presence do
   import LiveBeatsWeb.LiveHelpers
   @pubsub LiveBeats.PubSub
 
+  alias LiveBeats.Accounts
+
   def listening_now(assigns) do
     ~H"""
     <!-- users -->
@@ -33,6 +35,18 @@ defmodule LiveBeatsWeb.Presence do
     """
   end
 
+  def fetch(_topic, presences) do
+    users =
+      presences
+      |> Map.keys()
+      |> Accounts.get_users_map()
+      |> Enum.into(%{})
+
+    for {key, %{metas: metas}} <- presences, into: %{} do
+      {key, %{metas: metas, user: users[String.to_integer(key)]}}
+    end
+  end
+
   def subscribe(user_id) do
     Phoenix.PubSub.subscribe(@pubsub, topic(user_id))
   end

lib/live_beats_web/live/profile_live.ex

@@ -267,10 +267,7 @@ defmodule LiveBeatsWeb.ProfileLive do
     presences = socket.assigns.profile.user_id
     |> topic()
     |> LiveBeats.PresenceClient.list()
-    |> Enum.map(fn {user_id, _user_data} ->
-      user_id
-    end)
-    |> Accounts.list_users_by_ids()
+    |> Enum.map(fn {_key, meta} -> meta.user end)
 
     assign(socket, presences: presences)
   end