From a02ec174beb9a2a1037e30c87f3a8b6a3fa69ea8 Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Wed, 8 Sep 2021 09:35:46 -0400
Subject: [PATCH] Use unique index to prevent duplicate items from being
 created

---
 lib/frenzy/item.ex                                         | 5 +++++
 lib/frenzy/task/create_item.ex                             | 2 +-
 lib/frenzy/update_feeds.ex                                 | 4 +---
 .../migrations/20210908133238_creat_item_unique_index.exs  | 7 +++++++
 4 files changed, 14 insertions(+), 4 deletions(-)
 create mode 100644 priv/repo/migrations/20210908133238_creat_item_unique_index.exs

diff --git a/lib/frenzy/item.ex b/lib/frenzy/item.ex
index 76212e5..2b8bf08 100644
--- a/lib/frenzy/item.ex
+++ b/lib/frenzy/item.ex
@@ -83,5 +83,10 @@ defmodule Frenzy.Item do
     item
     |> cast(attrs, [:guid, :title, :url, :creator, :date, :content, :read, :read_date, :tombstone])
     |> validate_required([:guid, :url, :date, :content, :feed])
+    |> unique_constraint(:items_feed_guid_index)
+  end
+
+  def exists?(feed_id, guid) do
+    Frenzy.Repo.exists?(__MODULE__, feed_id: feed_id, guid: guid)
   end
 end
diff --git a/lib/frenzy/task/create_item.ex b/lib/frenzy/task/create_item.ex
index e654a2f..6d9b1bc 100644
--- a/lib/frenzy/task/create_item.ex
+++ b/lib/frenzy/task/create_item.ex
@@ -62,7 +62,7 @@ defmodule Frenzy.Task.CreateItem do
       end
 
     case result do
-      {:err, error} ->
+      {:error, error} ->
         Logger.error(error)
 
       {:ok, item_params} ->
diff --git a/lib/frenzy/update_feeds.ex b/lib/frenzy/update_feeds.ex
index 9898d04..c1f0dac 100644
--- a/lib/frenzy/update_feeds.ex
+++ b/lib/frenzy/update_feeds.ex
@@ -158,11 +158,9 @@ defmodule Frenzy.UpdateFeeds do
       FetchFavicon.run(feed)
     end
 
-    feed = Repo.preload(feed, [:items])
-
     Enum.each(rss.items, fn entry ->
       # todo: use Repo.exists for this
-      if !Enum.any?(feed.items, fn item -> item.guid == entry.guid end) do
+      unless Item.exists?(feed.id, entry.guid) do
         CreateItem.start_link(feed, entry)
       end
     end)
diff --git a/priv/repo/migrations/20210908133238_creat_item_unique_index.exs b/priv/repo/migrations/20210908133238_creat_item_unique_index.exs
new file mode 100644
index 0000000..07dd655
--- /dev/null
+++ b/priv/repo/migrations/20210908133238_creat_item_unique_index.exs
@@ -0,0 +1,7 @@
+defmodule Frenzy.Repo.Migrations.CreatItemUniqueIndex do
+  use Ecto.Migration
+
+  def change do
+    create unique_index(:items, [:feed_id, :guid], name: :items_feed_guid_index)
+  end
+end