FEATURE: move stylesheet cache out of the uploads directory

app/controllers/stylesheets_controller.rb

@@ -0,0 +1,33 @@
+class StylesheetsController < ApplicationController
+  skip_before_filter :preload_json, :redirect_to_login_if_required, :check_xhr, :verify_authenticity_token, only: [:show]
+
+  def show
+
+    target,digest = params[:name].split("_")
+
+    digest = "_" + digest if digest
+
+    # Security note, safe due to route constraint
+    location = "#{DiscourseStylesheets::CACHE_PATH}/#{target}#{digest}.css"
+
+    unless File.exist?(location)
+      query = StylesheetCache.where(target: target)
+      if digest
+        query = query.where(digest: digest)
+      else
+        query = query.order('id desc')
+      end
+
+      if current = query.first
+        File.write(location, current.content)
+      else
+        return render nothing: true, status: 404
+      end
+    end
+
+    expires_in 1.year, public: true unless Rails.env == "development"
+    send_file(location, disposition: :inline)
+
+  end
+end
+

app/models/stylesheet_cache.rb

@@ -0,0 +1,25 @@
+class StylesheetCache < ActiveRecord::Base
+  self.table_name = 'stylesheet_cache'
+
+  MAX_TO_KEEP = 10
+
+  def self.add(target,digest,content)
+    success = create(target: target, digest: digest, content: content)
+
+    count = StylesheetCache.count
+    if count > MAX_TO_KEEP
+
+      remove_lower = StylesheetCache.limit(MAX_TO_KEEP)
+                     .order('id desc')
+                     .pluck(:id)
+                     .last
+
+      exec_sql("DELETE FROM stylesheet_cache where id < :id", id: remove_lower)
+    end
+
+    success
+  rescue ActiveRecord::RecordNotUnique
+    false
+  end
+
+end

config/initializers/06-mini_profiler.rb

@@ -33,7 +33,8 @@ if defined?(Rack::MiniProfiler)
     /^\/site_customizations/,
     /^\/uploads/,
     /^\/javascripts\//,
-    /^\/images\//
+    /^\/images\//,
+    /^\/stylesheets\//
   ]
 
   # For our app, let's just show mini profiler always, polling is chatty so nuke that

config/nginx.sample.conf

@@ -158,7 +158,7 @@ server {
     # This big block is needed so we can selectively enable
     # acceleration for backups and avatars
     # see note about repetition above
-    location ~ ^/(letter_avatar|user_avatar|highlight-js) {
+    location ~ ^/(letter_avatar|user_avatar|highlight-js|stylesheets) {
       proxy_set_header Host $http_host;
       proxy_set_header X-Real-IP $remote_addr;
       proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

config/routes.rb

@@ -287,6 +287,8 @@ Discourse::Application.routes.draw do
 
   get "highlight-js/:hostname/:version.js" => "highlight_js#show", format: false, constraints: { hostname: /[\w\.-]+/ }
 
+  get "stylesheets/:name.css" => "stylesheets#show", constraints: {name: /[a-z0-9_]+/}
+
   get "uploads/:site/:id/:sha.:extension" => "uploads#show", constraints: {site: /\w+/, id: /\d+/, sha: /[a-z0-9]{15,16}/i, extension: /\w{2,}/}
   get "uploads/:site/:sha" => "uploads#show", constraints: { site: /\w+/, sha: /[a-z0-9]{40}/}
   post "uploads" => "uploads#create"

db/migrate/20150505044154_add_stylesheet_cache.rb

@@ -0,0 +1,12 @@
+class AddStylesheetCache < ActiveRecord::Migration
+  def change
+    create_table :stylesheet_cache do |t|
+      t.string :target, null: false
+      t.string :digest, null: false
+      t.text :content, null: false
+      t.timestamps
+    end
+
+    add_index :stylesheet_cache, [:target, :digest], unique: true
+  end
+end

lib/sass/discourse_stylesheets.rb

@@ -3,7 +3,7 @@ require_dependency 'distributed_cache'
 
 class DiscourseStylesheets
 
-  CACHE_PATH ||= 'uploads/stylesheet-cache'
+  CACHE_PATH ||= 'tmp/stylesheet-cache'
   MANIFEST_DIR ||= "#{Rails.root}/tmp/cache/assets/#{Rails.env}"
   MANIFEST_FULL_PATH ||= "#{MANIFEST_DIR}/stylesheet-manifest"
 
@@ -89,6 +89,7 @@ class DiscourseStylesheets
     File.open(stylesheet_fullpath, "w") do |f|
       f.puts css
     end
+    StylesheetCache.add(@target, digest, css)
     css
   end
 
@@ -100,7 +101,7 @@ class DiscourseStylesheets
   end
 
   def cache_fullpath
-    "#{Rails.root}/public/#{CACHE_PATH}"
+    "#{Rails.root}/#{CACHE_PATH}"
   end
 
   def stylesheet_fullpath
@@ -118,12 +119,13 @@ class DiscourseStylesheets
     "#{GlobalSetting.relative_url_root}/"
   end
 
+  # using uploads cause we already have all the routing in place
   def stylesheet_relpath
-    "#{root_path}#{CACHE_PATH}/#{stylesheet_filename}"
+    "#{root_path}stylesheets/#{stylesheet_filename}"
   end
 
   def stylesheet_relpath_no_digest
-    "#{root_path}#{CACHE_PATH}/#{stylesheet_filename_no_digest}"
+    "#{root_path}stylesheets/#{stylesheet_filename_no_digest}"
   end
 
   def stylesheet_filename

spec/models/stylesheet_cache_spec.rb

@@ -0,0 +1,24 @@
+require 'spec_helper'
+
+describe StylesheetCache do
+
+  describe "add" do
+    it "correctly cycles once MAX_TO_KEEP is hit" do
+      (StylesheetCache::MAX_TO_KEEP + 1).times do |i|
+        StylesheetCache.add(i.to_s, "d" + i.to_s, "c" + i.to_s)
+      end
+
+      expect(StylesheetCache.count).to eq StylesheetCache::MAX_TO_KEEP
+      expect(StylesheetCache.order(:id).first.content).to eq "c1"
+    end
+
+    it "does nothing if digest is set and already exists" do
+      StylesheetCache.add("a", "b", "c")
+      StylesheetCache.add("a", "b", "cc")
+
+      expect(StylesheetCache.count).to eq 1
+      expect(StylesheetCache.first.content).to eq "c"
+    end
+
+  end
+end