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/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
 
@@ -89,7 +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
@@ -100,8 +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)
 
@@ -115,15 +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