temp: stash presence

Author: maxneuvians

valentine/assets/css/app.css

@@ -464,4 +464,19 @@ table.summary td.inset {
 .tabnav-container .markdown ol,
 ul {
     padding-left: 1.5rem;
+}
+
+.presence-list {
+    display: inline;
+}
+
+.presence-list ul {
+    list-style: none;
+    padding: 0;
+    margin: 0;
+}
+
+.presence-list li {
+    display: inline;
+    margin-right: 0.5rem;
 }

valentine/lib/valentine/application.ex

@@ -12,6 +12,7 @@ defmodule Valentine.Application do
       Valentine.Repo,
       {DNSCluster, query: Application.get_env(:valentine, :dns_cluster_query) || :ignore},
       {Phoenix.PubSub, name: Valentine.PubSub},
+      ValentineWeb.Presence,
       # Start the Finch HTTP client for sending emails
       {Finch, name: Valentine.Finch},
       # Start a worker by calling: Valentine.Worker.start_link(arg)

valentine/lib/valentine_web/components/layouts/app.html.heex

@@ -6,6 +6,11 @@
       </.link>
     </:item>
     <:item is_full_width />
+    <:item>
+      <ValentineWeb.WorkspaceLive.Components.PresenceIndicatorComponent.render presence={
+        @presence
+      } />
+    </:item>
     <:item>
       <.button
         is_icon_button

valentine/lib/valentine_web/helpers/auth_helper.ex

@@ -27,7 +27,12 @@ defmodule ValentineWeb.Helpers.AuthHelper do
           {:cont, Phoenix.Component.assign(socket, :current_user, user_id)}
       end
     else
-      {:cont, Phoenix.Component.assign(socket, :current_user, nil)}
+      user_id =
+        Valentine.Cache.get({socket.id, :user_id}) || session["user_id"] || generate_user_id()
+
+      Valentine.Cache.put({socket.id, :user_id}, user_id, expire: :timer.hours(48))
+
+      {:cont, Phoenix.Component.assign(socket, :current_user, user_id)}
     end
   end
 
@@ -41,4 +46,10 @@ defmodule ValentineWeb.Helpers.AuthHelper do
       _ -> false
     end
   end
+
+  defp generate_user_id() do
+    :crypto.strong_rand_bytes(16)
+    |> Base.encode64()
+    |> String.trim_trailing("=")
+  end
 end

valentine/lib/valentine_web/helpers/nav_helper.ex

@@ -1,5 +1,6 @@
 defmodule ValentineWeb.Helpers.NavHelper do
   use ValentineWeb, :live_view
+  alias ValentineWeb.Presence
 
   def on_mount(:default, _params, _session, socket) do
     {:cont,
@@ -8,6 +9,8 @@ defmodule ValentineWeb.Helpers.NavHelper do
   end
 
   defp set_active_module(params, _url, socket) do
+    workspace_id = Map.get(params, "workspace_id", nil)
+
     active_module =
       socket.view
       |> to_string()
@@ -17,10 +20,16 @@ defmodule ValentineWeb.Helpers.NavHelper do
         [name | _] -> name
       end
 
+    Presence.track(self(), "valentine:presence", socket.assigns.current_user, %{
+      action: socket.assigns.live_action,
+      module: active_module,
+      workspace_id: workspace_id
+    })
+
     {:cont,
      socket
      |> assign(active_module: active_module)
      |> assign(active_action: socket.assigns.live_action)
-     |> assign(:workspace_id, if(params["workspace_id"], do: params["workspace_id"], else: nil))}
+     |> assign(:workspace_id, workspace_id)}
   end
 end

valentine/lib/valentine_web/helpers/presence_helper.ex

@@ -0,0 +1,22 @@
+defmodule ValentineWeb.Helpers.PresenceHelper do
+  import Phoenix.LiveView
+
+  def on_mount(_name, _params, _session, socket) do
+    if connected?(socket) do
+      Phoenix.PubSub.subscribe(Valentine.PubSub, "valentine:presence")
+    end
+
+    {:cont,
+     socket
+     |> Phoenix.Component.assign(:presence, Valentine.Cache.get("valentine:presence") || %{})
+     |> attach_hook(:presence_update, :handle_info, &handle_info/2)}
+  end
+
+  defp handle_info(%{event: "presence_diff"}, socket) do
+    {:halt,
+     socket
+     |> Phoenix.Component.assign(:presence, Valentine.Cache.get("valentine:presence") || %{})}
+  end
+
+  defp handle_info(_, socket), do: {:cont, socket}
+end

valentine/lib/valentine_web/live/workspace_live/components/presence_indicator_component.ex

@@ -0,0 +1,38 @@
+defmodule ValentineWeb.WorkspaceLive.Components.PresenceIndicatorComponent do
+  use Phoenix.Component
+  use PrimerLive
+
+  attr :presence, :map, default: %{}
+
+  def render(assigns) do
+    ~H"""
+    <div class="presence-list">
+      <ul>
+        <%= for {{key, _presence}, index} <- @presence |> Enum.with_index() do %>
+          <li title={key}>
+            <.counter style={"color: #{get_colour(index)}; background-color: #{get_colour(index)}"}>
+              {index}
+            </.counter>
+          </li>
+        <% end %>
+      </ul>
+    </div>
+    """
+  end
+
+  defp get_colour(index) when index > 8, do: get_colour(index - 9)
+  defp get_colour(index) do
+    [
+      "#2cbe4e",
+      "#f9826c",
+      "#fbbc05",
+      "#f96233",
+      "#f24e1e",
+      "#dbab09",
+      "#b08800",
+      "#735c0f",
+      "#3f2c00"
+    ]
+    |> Enum.at(index)
+  end
+end

valentine/lib/valentine_web/presence.ex

@@ -0,0 +1,20 @@
+defmodule ValentineWeb.Presence do
+  use Phoenix.Presence,
+    otp_app: :my_app,
+    pubsub_server: Valentine.PubSub
+
+  def init(_opts) do
+    # user-land state
+    {:ok, %{}}
+  end
+
+  def handle_metas(_topic, %{joins: joins, leaves: leaves}, _presences, state) do
+    presence =
+      (Valentine.Cache.get("valentine:presence") || %{})
+      |> Map.merge(joins)
+      |> Map.drop(Map.keys(leaves))
+
+    Valentine.Cache.put("valentine:presence", presence)
+    {:ok, state}
+  end
+end

valentine/lib/valentine_web/router.ex

@@ -53,6 +53,7 @@ defmodule ValentineWeb.Router do
         ValentineWeb.Helpers.FlashHelper,
         ValentineWeb.Helpers.LocaleHelper,
         ValentineWeb.Helpers.NavHelper,
+        ValentineWeb.Helpers.PresenceHelper,
         ValentineWeb.Helpers.ThemeHelper
       ] do
       live "/workspaces", WorkspaceLive.Index, :index

valentine/test/valentine_web/helpers/auth_helper_test.exs

@@ -74,13 +74,15 @@ defmodule ValentineWeb.Helpers.AuthHelperTest do
   end
 
   describe "on_mount/4" do
-    test "sets the current_user to nil if GOOGLE env variables are not set", %{socket: socket} do
+    test "sets the current_user to a random ID if GOOGLE env variables are not set", %{
+      socket: socket
+    } do
       System.put_env("GOOGLE_CLIENT_ID", "")
       System.put_env("GOOGLE_CLIENT_SECRET", "")
 
       {:cont, socket} = AuthHelper.on_mount(:default, %{}, %{}, socket)
 
-      assert socket.assigns[:current_user] == nil
+      assert socket.assigns[:current_user] != nil
     end
 
     test "halts and redirects to / if user_id is nil", %{socket: socket} do