use nokogiri for rss, return better results, index for speed

Gemfile

@@ -52,7 +52,6 @@ gem 'facter', require: nil
 gem 'maxmind-db'
 gem 'json', '>= 2.3.0'
 gem 'nokogiri'
-gem 'rss'
 gem 'webp-ffi'
 gem 'rszr'
 gem 'zip_tricks'

Gemfile.lock

@@ -254,8 +254,6 @@ GEM
       netrc (~> 0.8)
     rexml (3.2.6)
     rinku (2.0.6)
-    rss (0.3.0)
-      rexml
     rszr (1.3.0)
     ruby-progressbar (1.13.0)
     ruby2_keywords (0.0.5)
@@ -403,7 +401,6 @@ DEPENDENCIES
   redis-namespace
   rest-client
   rinku
-  rss
   rszr
   rubyzip
   sanitize

app/site.rb

@@ -2,7 +2,7 @@ get '/site/:username.rss' do |username|
   site = Site[username: username]
   halt 404 if site.nil?
   content_type :xml
-  site.to_rss.to_xml
+  site.to_rss
 end
 
 get '/site/:username/?' do |username|
@@ -374,4 +374,4 @@ post '/site/:username/confirm_phone' do
 
   # Will redirect to / automagically if phone was verified
   redirect "/site/#{current_site.username}/confirm_phone"
-end
+end

migrations/123_events_rss_index.rb

@@ -0,0 +1,9 @@
+Sequel.migration do
+  up {
+    DB.add_index :events, [:created_at, :site_id, :site_change_id, :is_deleted], name: :events_rss_index, order: {created_at: :desc}
+  }
+
+  down {
+    DB.drop_index :events, :rss
+  }
+end

models/site.rb

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 require 'tilt'
-require 'rss'
 require 'nokogiri'
 require 'pathname'
 require 'zlib'
@@ -1526,24 +1525,30 @@ class Site < Sequel::Model
   end
 
   def to_rss
-    RSS::Maker.make("2.0") do |m|
-      m.channel.title = title
-      m.channel.link = uri
-      m.channel.description = "Site feed for #{title}"
-      m.image.url = sharing_screenshot_url
-      m.image.title = title
+    site_change_events = events_dataset.exclude(is_deleted: true).exclude(site_change_id: nil).order(:created_at.desc).limit(10).all
 
+    Nokogiri::XML::Builder.new(encoding: 'UTF-8') do |xml|
+      xml.rss('version' => '2.0') {
+        xml.channel {
+          xml.title title
+          xml.link uri
+          xml.description "Site feed for #{title}"
+          xml.image {
+            xml.url sharing_screenshot_url
+            xml.title title
+          }
 
-      latest_events.each do |event|
-        if event.site_change_id
-          m.items.new_item do |i|
-            i.title = "#{title} has been updated."
-            i.link = "https://neocities.org/site/#{username}?event_id=#{event.id.to_s}"
-            i.pubDate = event.created_at
+          site_change_events.each do |event|
+            xml.item {
+              xml.title "#{title} has been updated."
+              xml.link "https://neocities.org/site/#{username}?event_id=#{event.id.to_s}"
+              xml.pubDate event.created_at.rfc822
+              xml.guid event.id.to_s
+            }
           end
-        end
-      end
-    end
+        }
+      }
+    end.to_xml
   end
 
   def empty_index?