refactor(notification): cut from_users with count

lib/groupher_server/delivery/delegates/notification.ex

@@ -18,6 +18,7 @@ defmodule GroupherServer.Delivery.Delegate.Notification do
 
   @notify_actions get_config(:general, :nofity_actions)
   @notify_group_interval_hour get_config(:general, :notify_group_interval_hour)
+  @cut_from_users_count 3
 
   def handle(%{action: action, user_id: user_id} = attrs, %User{} = from_user) do
     with true <- action in @notify_actions,
@@ -84,9 +85,21 @@ defmodule GroupherServer.Delivery.Delegate.Notification do
     Notification
     |> where([n], n.user_id == ^user.id and n.read == ^read)
     |> ORM.paginater(~m(page size)a)
+    |> cut_from_users_ifneed
     |> done
   end
 
+  # @cut_from_users_count
+  defp cut_from_users_ifneed(%{entries: entries} = paged_contents) do
+    entries =
+      Enum.map(entries, fn notify ->
+        from_users = Enum.slice(notify.from_users, 0, @cut_from_users_count)
+        notify |> Map.put(:from_users, from_users)
+      end)
+
+    paged_contents |> Map.put(:entries, entries)
+  end
+
   # 注意这里并不是准确的 count, 因为可能有短时间内 merge 到一起的通知
   def unread_count(user_id) do
     Notification
@@ -114,13 +127,18 @@ defmodule GroupherServer.Delivery.Delegate.Notification do
     cur_from_users = notify.from_users |> Enum.map(&strip_struct(&1))
     from_users = ([from_user] ++ cur_from_users) |> Enum.uniq()
 
-    notify |> ORM.update_embed(:from_users, from_users)
+    notify
+    |> Ecto.Changeset.change(%{from_users_count: length(from_users)})
+    |> Ecto.Changeset.put_embed(:from_users, from_users)
+    |> Repo.update()
   end
 
   # 创建通知
   defp create_notification(attrs, from_user) do
+    attrs = attrs |> Map.merge(%{from_users_count: 1}) |> atom_values_to_upcase
+
     %Notification{}
-    |> Ecto.Changeset.change(atom_values_to_upcase(attrs))
+    |> Ecto.Changeset.change(attrs)
     |> Ecto.Changeset.put_embed(:from_users, [from_user])
     |> Repo.insert()
   end

lib/groupher_server/delivery/models/notification.ex

@@ -24,6 +24,7 @@ defmodule GroupherServer.Delivery.Model.Notification do
     #
     field(:action, :string)
     embeds_many(:from_users, Embeds.User, on_replace: :delete)
+    field(:from_users_count, :integer)
 
     field(:read, :boolean, default: false)
 

lib/groupher_server_web/schema/account/account_types.ex

@@ -122,6 +122,7 @@ defmodule GroupherServerWeb.Schema.Account.Types do
     field(:read, :boolean)
 
     field(:from_users, list_of(:common_user))
+    field(:from_users_count, :integer)
 
     timestamp_fields()
   end

priv/repo/migrations/20210623054015_add_from_users_count_to_notification.exs

@@ -0,0 +1,9 @@
+defmodule GroupherServer.Repo.Migrations.AddFromUsersCountToNotification do
+  use Ecto.Migration
+
+  def change do
+    alter table(:notifications) do
+      add(:from_users_count, :integer)
+    end
+  end
+end

test/groupher_server/delivery/notification_test.exs

@@ -137,6 +137,28 @@ defmodule GroupherServer.Test.Delivery.Notification do
       assert user2 |> user_exist_in?(notify2.from_users)
     end
 
+    test "notify's from_users_count should work", ~m(user user2 user3 user4 notify_attrs)a do
+      {:ok, user5} = db_insert(:user)
+
+      {:ok, _notify} = Delivery.send(:notify, notify_attrs, user2)
+      {:ok, _} = Delivery.send(:notify, notify_attrs, user3)
+      {:ok, _} = Delivery.send(:notify, notify_attrs, user4)
+      {:ok, _} = Delivery.send(:notify, notify_attrs, user5)
+
+      {:ok, paged_notifies} = Delivery.fetch(:notification, user, %{page: 1, size: 10})
+
+      assert paged_notifies.total_count == 1
+      notify = paged_notifies.entries |> List.first()
+
+      assert notify.from_users_count == 4
+      assert length(notify.from_users) == 3
+
+      assert user5 |> user_exist_in?(notify.from_users)
+      assert user4 |> user_exist_in?(notify.from_users)
+      assert user3 |> user_exist_in?(notify.from_users)
+      assert not user_exist_in?(user2, notify.from_users)
+    end
+
     test "notify myself got ignored", ~m(user notify_attrs)a do
       {:error, _} = Delivery.send(:notify, notify_attrs, user)
     end