correct headers and add better caching

app/controllers/static_controller.rb

@@ -136,6 +136,7 @@ class StaticController < ApplicationController
     opts[:type] = "application/javascript" if path =~ /\.js.br$/
 
     response.headers["Expires"] = 1.year.from_now.httpdate
+    response.headers["Cache-Control"] = 'max-age=31557600, public'
     response.headers["Content-Encoding"] = 'br'
     begin
       response.headers["Last-Modified"] = File.ctime(path).httpdate

app/helpers/application_helper.rb

@@ -49,7 +49,7 @@ module ApplicationHelper
     if  GlobalSetting.cdn_url &&
         GlobalSetting.cdn_url.start_with?("https") &&
         ENV["COMPRESS_BROTLI"] == "1" &&
-        request.env["ACCEPT_ENCODING"] =~ /br/
+        request.env["HTTP_ACCEPT_ENCODING"] =~ /br/
       tags = javascript_include_tag(*args)
       tags.gsub!("#{GlobalSetting.cdn_url}/assets/", "#{GlobalSetting.cdn_url}/brotli_asset/")
       tags.html_safe