readonly mode

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

@@ -8,8 +8,9 @@ Discourse.addInitializer(function() {
 
   Discourse.MessageBus.alwaysLongPoll = Discourse.Environment === "development";
   Discourse.MessageBus.start();
+
   Discourse.MessageBus.subscribe("/global/asset-version", function(version){
-    Discourse.set("assetVersion",version);
+    Discourse.set("assetVersion", version);
 
     if(Discourse.get("requiresRefresh")) {
       // since we can do this transparently for people browsing the forum
@@ -24,5 +25,15 @@ Discourse.addInitializer(function() {
     }
 
   });
+
+  Discourse.set("isReadOnly", Discourse.Site.currentProp("is_readonly"));
+
+  Discourse.MessageBus.subscribe("/global/read-only", function (enabled) {
+    Discourse.set("isReadOnly", enabled);
+    if (enabled) {
+      bootbox.alert(I18n.t("read_only_mode_enabled"));
+    }
+  });
+
   Discourse.KeyValueStore.init("discourse_", Discourse.MessageBus);
 }, true);

app/controllers/application_controller.rb

@@ -29,7 +29,7 @@ class ApplicationController < ActionController::Base
   before_filter :set_mobile_view
   before_filter :inject_preview_style
   before_filter :disable_customization
-  before_filter :block_if_maintenance_mode
+  before_filter :block_if_readonly_mode
   before_filter :authorize_mini_profiler
   before_filter :store_incoming_links
   before_filter :preload_json
@@ -50,7 +50,6 @@ class ApplicationController < ActionController::Base
     raise
   end
 
-
   # Some exceptions
   class RenderEmpty < Exception; end
 
@@ -87,6 +86,11 @@ class ApplicationController < ActionController::Base
     rescue_discourse_actions("[error: 'invalid access']", 403) # TODO: this breaks json responses
   end
 
+  rescue_from Discourse::ReadOnly do
+    # can this happen on a not .json format?
+    render json: failed_json.merge(message: I18n.t("read_only_mode_enabled"))
+  end
+
   def rescue_discourse_actions(message, error)
     if request.format && request.format.json?
       # TODO: this doesn't make sense. Stuffing an html page into a json response will cause
@@ -249,16 +253,6 @@ class ApplicationController < ActionController::Base
       end
     end
 
-    def block_if_maintenance_mode
-      if Discourse.maintenance_mode?
-        if request.format.json?
-          render status: 503, json: failed_json.merge(message: I18n.t('site_under_maintenance'))
-        else
-          render status: 503, file: File.join( Rails.root, 'public', '503.html' ), layout: false
-        end
-      end
-    end
-
     def mini_profiler_enabled?
       defined?(Rack::MiniProfiler) && current_user.try(:admin?)
     end
@@ -288,6 +282,11 @@ class ApplicationController < ActionController::Base
       redirect_to :login if SiteSetting.login_required?
     end
 
+    def block_if_readonly_mode
+      return if request.put? && request.fullpath == "/admin/backups/readonly"
+      raise Discourse::ReadOnly.new unless request.get? || !Discourse.readonly_mode?
+    end
+
     def build_not_found_page(status=404, layout=false)
       @top_viewed = Topic.top_viewed(10)
       @recent = Topic.recent(10)

app/serializers/site_serializer.rb

@@ -8,7 +8,8 @@ class SiteSerializer < ApplicationSerializer
              :periods,
              :top_menu_items,
              :anonymous_top_menu_items,
-             :uncategorized_category_id # this is hidden so putting it here
+             :uncategorized_category_id, # this is hidden so putting it here
+             :is_readonly
 
   has_many :categories, serializer: BasicCategorySerializer, embed: :objects
   has_many :post_action_types, embed: :objects
@@ -45,4 +46,8 @@ class SiteSerializer < ApplicationSerializer
     SiteSetting.uncategorized_category_id
   end
 
+  def is_readonly
+    Discourse.readonly_mode?
+  end
+
 end