From 308e3670df3b8ed67498da0b5e07c25a01e528d3 Mon Sep 17 00:00:00 2001
From: r888888888 <r888888888@gmail.com>
Date: Mon, 5 Feb 2018 12:38:01 -0800
Subject: [PATCH] gracefully handle unavailable pg connection errors

---
 app/controllers/application_controller.rb     | 13 +++++++++++++
 app/views/static/service_unavailable.html.erb |  3 +++
 2 files changed, 16 insertions(+)
 create mode 100644 app/views/static/service_unavailable.html.erb

diff --git a/app/controllers/application_controller.rb b/app/controllers/application_controller.rb
index 1ffab68c5..928398ed4 100644
--- a/app/controllers/application_controller.rb
+++ b/app/controllers/application_controller.rb
@@ -19,6 +19,7 @@ class ApplicationController < ActionController::Base
   rescue_from User::PrivilegeError, :with => :access_denied
   rescue_from SessionLoader::AuthenticationFailure, :with => :authentication_failed
   rescue_from Danbooru::Paginator::PaginationError, :with => :render_pagination_limit
+  rescue_from PG::ConnectionBad, with: :bad_db_connection
 
   # This is raised on requests to `/blah.js`. Rails has already rendered StaticController#not_found
   # here, so calling `rescue_exception` would cause a double render error.
@@ -45,6 +46,18 @@ class ApplicationController < ActionController::Base
     end
   end
   
+  def bad_db_connection
+    respond_to do |format|
+      format.json do
+        render json: {success: false, reason: "database is unavailable"}.to_json, status: 503
+      end
+
+      format.html do
+        render template: "static/service_unavailable", status: 503
+      end
+    end
+  end
+
   def api_check
     if !CurrentUser.is_anonymous? && !request.get? && !request.head?
       if CurrentUser.user.token_bucket.nil?
diff --git a/app/views/static/service_unavailable.html.erb b/app/views/static/service_unavailable.html.erb
new file mode 100644
index 000000000..826dc5210
--- /dev/null
+++ b/app/views/static/service_unavailable.html.erb
@@ -0,0 +1,3 @@
+<h1>Service Unavailable</h1>
+
+<p>Try again later</p>
\ No newline at end of file