FEATURE: automatically update site to latest version of assets

if a user neglects to move around the site it will prompt to do so 2 hours in

app/assets/javascripts/discourse.js

@@ -130,6 +130,11 @@ window.Discourse = Ember.Application.createWithMixins(Discourse.Ajax, {
     }
   },
 
+  requiresRefresh: function(){
+    var desired = Discourse.get("desiredAssetVersion");
+    return desired && Discourse.get("currentAssetVersion") !== desired;
+  }.property("currentAssetVersion", "desiredAssetVersion"),
+
   assetVersion: function(prop, val) {
     if(val) {
       if(this.get("currentAssetVersion")){

app/assets/javascripts/discourse/initializers/1_init_message_bus.js

@@ -6,6 +6,17 @@ Discourse.addInitializer(function() {
   Discourse.MessageBus.start();
   Discourse.MessageBus.subscribe("/global/asset-version", function(version){
     Discourse.set("assetVersion",version);
+
+    if(Discourse.get("requiresRefresh")) {
+      // since we can do this transparently for people browsing the forum
+      //  hold back the message a couple of hours
+      setTimeout(function() {
+        bootbox.confirm(I18n.lookup("assets_changed_confirm"), function(){
+          document.location.reload();
+        });
+      }, 1000 * 60 * 120);
+    }
+
   });
   Discourse.KeyValueStore.init("discourse_", Discourse.MessageBus);
 }, true);

app/assets/javascripts/discourse/lib/url.js

@@ -48,13 +48,9 @@ Discourse.URL = Em.Object.createWithMixins({
   **/
   routeTo: function(path) {
 
-    // If somehow our asset version changed, force a full reload of desired path
-    var desired = Discourse.get("desiredAssetVersion");
-    if(desired) {
-      if(Discourse.get("currentAssetVersion") !== desired){
-        document.location.href = path;
-        return;
-      }
+    if(Discourse.get("requiresRefresh")){
+      document.location.href = path;
+      return;
     }
 
     var oldPath = window.location.pathname;

app/views/common/_discourse_javascript.html.erb

@@ -37,7 +37,7 @@
   Discourse.SiteSettings = PreloadStore.get('siteSettings');
   Discourse.Router.map(function() { Discourse.routeBuilder.call(this); });
   Discourse.start()
-  Discourse.set('assetVersion','<%= Rails.application.assets.digest %>');
+  Discourse.set('assetVersion','<%= Discourse.assets_digest %>');
 </script>
 
 <%= javascript_include_tag 'browser-update.js' %>

config/initializers/04-message_bus.rb

@@ -37,11 +37,3 @@
 
 MessageBus.cache_assets = !Rails.env.development?
 MessageBus.enable_diagnostics
-
-digest = Rails.application.assets.digest.to_s
-channel = "/global/asset-version"
-message = MessageBus.last_message(channel)
-
-unless message && message.data == digest
-  MessageBus.publish channel, digest
-end

config/locales/client.en.yml

@@ -387,6 +387,7 @@ en:
 
     loading: "Loading..."
     close: "Close"
+    assets_changed_confirm: "Discourse has been updated, would you like to refresh to get the latest version?"
     learn_more: "learn more..."
 
     year: 'year'

lib/discourse.rb

@@ -59,6 +59,20 @@ def self.plugins
     @plugins
   end
 
+  def self.assets_digest
+    @assets_digest ||= begin
+      digest = Digest::MD5.hexdigest(ActionView::Base.assets_manifest.assets.values.sort.join)
+
+      channel = "/global/asset-version"
+      message = MessageBus.last_message(channel)
+
+      unless message && message.data == digest
+        MessageBus.publish channel, digest
+      end
+      digest
+    end
+  end
+
   def self.authenticators
     # TODO: perhaps we don't need auth providers and authenticators maybe one object is enough