related tags: eliminate favorite_tags cookie (#3955).

app/logical/related_tag_query.rb

@@ -1,7 +1,8 @@
 class RelatedTagQuery
-  attr_reader :query, :category, :translated_tags, :artists
+  attr_reader :query, :category, :translated_tags, :artists, :user
 
-  def initialize(query, category: nil, translated_tags: nil, artists: nil);
+  def initialize(query, category: nil, translated_tags: nil, artists: nil, user: nil)
+    @user = user
     @query = TagAlias.to_aliased(query.to_s.downcase.strip).join(" ")
     @category = category
     @translated_tags = translated_tags.to_s.split
@@ -25,6 +26,10 @@ class RelatedTagQuery
     end
   end
 
+  def favorite_tags
+    user&.favorite_tags.to_s.split
+  end
+
   def wiki_page_tags
     results = wiki_page.try(:tags) || []
     results.reject! do |name|

app/logical/session_loader.rb

@@ -28,7 +28,6 @@ class SessionLoader
     update_last_logged_in_at
     update_last_ip_addr
     set_time_zone
-    store_favorite_tags_in_cookies
     CurrentUser.user.unban! if CurrentUser.user.ban_expired?
   end
 
@@ -92,14 +91,6 @@ private
     cookies[:password_hash] && cookies.signed[:user_name] && User.authenticate_cookie_hash(cookies.signed[:user_name], cookies[:password_hash])
   end
 
-  def store_favorite_tags_in_cookies
-    if (cookies[:favorite_tags].blank? || cookies[:favorite_tags_with_categories].blank?) && CurrentUser.user.favorite_tags.present?
-      favorite_tags = CurrentUser.user.favorite_tags.slice(0, 1024)
-      cookies[:favorite_tags] = favorite_tags
-      cookies[:favorite_tags_with_categories] = Tag.categories_for(favorite_tags.split(/[[:space:]]+/)).to_a.flatten.join(" ")
-    end
-  end
-
   def update_last_logged_in_at
     return if CurrentUser.is_anonymous?
     return if CurrentUser.last_logged_in_at && CurrentUser.last_logged_in_at > 1.week.ago