Fix #4111: Cache custom CSS.

app/controllers/users_controller.rb

@@ -75,6 +75,11 @@ class UsersController < ApplicationController
     end
   end
 
+  def custom_style
+    @css = CustomCss.parse(CurrentUser.user.custom_style)
+    expires_in 10.years
+  end
+
   private
 
   def check_privilege(user)

app/logical/custom_css.rb

@@ -0,0 +1,11 @@
+module CustomCss
+  def self.parse(css)
+    css.to_s.split(/\r\n|\r|\n/).map do |line|
+      if line =~ /\A@import/
+        line
+      else
+        line.gsub(/([^[:space:]])[[:space:]]*(?:!important)?[[:space:]]*(;|})/, "\\1 !important\\2")
+      end
+    end.join("\n")
+  end
+end

app/presenters/user_presenter.rb

@@ -172,14 +172,4 @@ class UserPresenter
   def previous_names(template)
     user.user_name_change_requests.map { |req| template.link_to req.original_name, req }.join(", ").html_safe
   end
-
-  def custom_css
-    user.custom_style.to_s.split(/\r\n|\r|\n/).map do |line|
-      if line =~ /\A@import/
-        line
-      else
-        line.gsub(/([^[:space:]])[[:space:]]*(?:!important)?[[:space:]]*(;|})/, "\\1 !important\\2")
-      end
-    end.join("\n")
-  end
 end

app/views/layouts/default.html.erb

@@ -32,7 +32,7 @@
   <%= javascript_pack_tag "application" %>
   <%= stylesheet_pack_tag "application" %>
   <% if CurrentUser.user.custom_style.present? %>
-    <%= stylesheet_link_tag custom_style_users_path, :media => "screen" %>
+    <%= stylesheet_link_tag custom_style_users_path(md5: Digest::MD5.hexdigest(CurrentUser.user.custom_style)), media: "screen" %>
   <% end %>
   <% if Danbooru.config.twitter_site %>
     <script type="application/ld+json">

app/views/users/custom_style.css.erb

@@ -1 +1 @@
-<%= raw CurrentUser.user.presenter.custom_css %>
+<%= raw @css %>