Add feed filters

lib/frenzy/filter_engine.ex

@@ -0,0 +1,33 @@
+defmodule Frenzy.FilterEngine do
+  def matches?(item, filter) do
+    score =
+      filter.rules
+      |> Enum.map(fn rule -> score(item, rule) end)
+      |> Enum.sum()
+
+    score >= filter.score
+  end
+
+  def score(item, rule) do
+    prop_value = get_property(item, rule.property)
+
+    if matches(prop_value, rule.mode, rule.param) do
+      rule.weight
+    else
+      0
+    end
+  end
+
+  def matches(value, "contains_string", param) do
+    String.contains?(value, param)
+  end
+
+  def matches(value, "matches_regex", param) do
+    regex = Regex.compile(param)
+    String.match?(value, regex)
+  end
+
+  def get_property(item, "url"), do: item.url
+  def get_property(item, "title"), do: item.title
+  def get_property(item, "author"), do: item.author
+end

lib/frenzy/item.ex

@@ -25,6 +25,7 @@ defmodule Frenzy.Item do
     field :read, :boolean, default: false
     field :read_date, :utc_datetime
     field :title, :string
+    field :tombstone, :boolean, default: false
 
     belongs_to :feed, Frenzy.Feed
 
@@ -34,7 +35,7 @@ defmodule Frenzy.Item do
   @doc false
   def changeset(item, attrs) do
     item
-    |> cast(attrs, [:guid, :title, :url, :creator, :date, :content, :read, :read_date])
+    |> cast(attrs, [:guid, :title, :url, :creator, :date, :content, :read, :read_date, :tombstone])
     |> validate_required([:guid, :title, :url, :date, :content, :feed])
   end
 end

lib/frenzy/update_feeds.ex

@@ -1,6 +1,6 @@
 defmodule Frenzy.UpdateFeeds do
   use GenServer
-  alias Frenzy.{Repo, Feed, Item}
+  alias Frenzy.{Repo, Feed, Item, FilterEngine}
   import Ecto.Query
   require Logger
 
@@ -32,22 +32,33 @@ defmodule Frenzy.UpdateFeeds do
 
   defp schedule_update() do
     # 15 minutes
-    Process.send_after(self(), :update_feeds, 15 * 60 * 1000)
-    # Process.send_after(self(), :update_feeds, 60 * 1000) # 1 minutes
+    # Process.send_after(self(), :update_feeds, 15 * 60 * 1000)
+    # 1 minutes
+    Process.send_after(self(), :update_feeds, 60 * 1000)
   end
 
   defp update_feeds() do
     Logger.info("Updating all feeds")
 
-    Enum.map(Repo.all(Feed), &update_feed/1)
+    Repo.all(from Feed, preload: [:filter])
+    |> Enum.map(&update_feed/1)
+
     prune_old_items()
   end
 
   defp prune_old_items() do
     {count, _} =
-      Repo.delete_all(from i in Item, where: i.read, where: i.read_date <= from_now(-1, "week"))
+      from(i in Item,
+        where: i.read and not i.tombstone,
+        # where: i.read_date <= from_now(-1, "week"),
+        where: i.read_date <= from_now(-1, "minute"),
+        update: [
+          set: [tombstone: true, content: nil, creator: nil, date: nil, url: nil, title: nil]
+        ]
+      )
+      |> Repo.update_all([])
 
-    Logger.info("Removed #{count} read items")
+    Logger.info("Converted #{count} read items to tombstones")
   end
 
   defp update_feed(feed) do
@@ -78,7 +89,7 @@ defmodule Frenzy.UpdateFeeds do
 
     Repo.update(changeset)
 
-    feed = Repo.preload(feed, :items)
+    feed = Repo.preload(feed, items: [], filter: [:rules])
 
     Enum.map(rss.items, fn entry ->
       # todo: use Repo.exists for this
@@ -89,8 +100,7 @@ defmodule Frenzy.UpdateFeeds do
   end
 
   defp create_item(feed, entry) do
-    Logger.debug("Creating item for:")
-    IO.inspect(entry)
+    Logger.debug("Creating item for #{entry.url}")
 
     url = get_real_url(entry)
 
@@ -104,15 +114,43 @@ defmodule Frenzy.UpdateFeeds do
           entry.description
       end
 
-    changeset =
-      Ecto.build_assoc(feed, :items, %{
+    item_params = %{
       guid: entry.id,
       title: entry.title,
       url: url,
       date: parse_date(entry.published_at),
       creator: "",
       content: content
+    }
+
+    result =
+      if feed.filter_enabled do
+        case {feed.filter.mode, FilterEngine.matches?(item_params, feed.filter)} do
+          {"accept", true} ->
+            :store
+
+          {"reject", false} ->
+            :store
+
+          _ ->
+            Logger.debug("Skipping item #{url} due to feed filter")
+            :tombstone
+        end
+      else
+        :store
+      end
+
+    changeset =
+      case result do
+        :store ->
+          Ecto.build_assoc(feed, :items, item_params)
+
+        :tombstone ->
+          Ecto.build_assoc(feed, :items, %{
+            guid: entry.id,
+            tombstone: true
           })
+      end
 
     Repo.insert(changeset)
   end

lib/frenzy_web/controllers/feed_controller.ex

@@ -11,7 +11,7 @@ defmodule FrenzyWeb.FeedController do
 
   def show(conn, %{"id" => id}) do
     feed = Repo.get(Feed, id) |> Repo.preload(:filter)
-    items = Repo.all(from Item, where: [feed_id: ^id], order_by: [desc: :date])
+    items = Repo.all(from Item, where: [feed_id: ^id, tombstone: false], order_by: [desc: :date])
 
     render(conn, "show.html", %{
       feed: feed,
@@ -39,6 +39,15 @@ defmodule FrenzyWeb.FeedController do
       )
 
     {:ok, feed} = Repo.insert(changeset)
+
+    # changeset =
+    #   Ecto.build_assoc(feed, :filter, %{
+    #     mode: "reject",
+    #     score: 0
+    #   })
+
+    # {:ok, _} = Repo.insert(changeset)
+
     redirect(conn, to: Routes.feed_path(Endpoint, :index))
   end
 

priv/repo/migrations/20190310234846_items_add_tombstone.exs

@@ -0,0 +1,9 @@
+defmodule Frenzy.Repo.Migrations.ItemsAddTombstone do
+  use Ecto.Migration
+
+  def change do
+    alter table(:items) do
+      add :tombstone, :boolean
+    end
+  end
+end