FEATURE: allow a central redis cache for assets

config/discourse_defaults.conf

@@ -88,6 +88,9 @@ redis_db = 0
 # redis password
 redis_password =
 
+# eg: redis://:password@host:port
+asset_redis_url =
+
 # enable Cross-origin Resource Sharing (CORS) directly at the application level
 enable_cors = false
 cors_origin = '*'

config/routes.rb

@@ -245,8 +245,8 @@ Discourse::Application.routes.draw do
   get "user_avatar/:hostname/:username/:size/:version.png" => "user_avatars#show",
       format: false, constraints: {hostname: /[\w\.-]+/}
 
-
   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"
 
   get "posts/by_number/:topic_id/:post_number" => "posts#by_number"

lib/tasks/assets.rake

@@ -21,14 +21,31 @@ task 'assets:precompile:before' do
 
   module ::Sprockets
 
+    def self.redis
+      @redis ||=
+        (
+          redis_url = GlobalSetting.asset_redis_url
+          if redis_url.present?
+            uri = URI.parse(redis_url)
+            options = {}
+            options[:password] = uri.password if uri.password.present?
+            options[:host] = uri.host
+            options[:port] = uri.port || 6379
+            Redis.new(options)
+          else
+            DiscourseRedis.raw_connection
+          end
+        )
+    end
+
     def self.cache_compiled(type, data)
       digest = Digest::SHA1.hexdigest(data)
       key = "SPROCKETS_#{type}_#{digest}"
-      if compiled = $redis.get(key)
-        $redis.expire(key, 1.week)
+      if compiled = redis.get(key)
+        redis.expire(key, 1.week)
       else
         compiled = yield
-        $redis.setex(key, 1.week, compiled)
+        redis.setex(key, 1.week, compiled)
       end
       compiled
     end