Use a redis-cached feed for the DM timeline

app/models/direct_feed.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class DirectFeed < Feed
+  include Redisable
+
+  def initialize(account)
+    @type    = :direct
+    @id      = account.id
+    @account = account
+  end
+
+  def get(limit, max_id = nil, since_id = nil, min_id = nil)
+    unless redis.exists("account:#{@account.id}:regeneration")
+      statuses = super
+      return statuses unless statuses.empty?
+    end
+    from_database(limit, max_id, since_id, min_id)
+  end
+
+  private
+
+  def from_database(limit, max_id, since_id, min_id)
+    loop do
+      statuses = Status.as_direct_timeline(@account, limit, max_id, since_id, min_id)
+      return statuses if statuses.empty?
+      max_id = statuses.last.id
+      statuses = statuses.reject { |status| FeedManager.instance.filter?(:direct, status, @account.id) }
+      return statuses unless statuses.empty?
+    end
+  end
+end