Add endpoint for checking subscription status

app/controllers/ajax/web_push_controller.rb

@@ -11,6 +11,23 @@ class Ajax::WebPushController < AjaxController
     @response[:key] = JSON.parse(certificate)["public_key"]
   end
 
+  def check
+    params.permit(:endpoint)
+
+    found = WebPushSubscription.where("subscription ->> 'endpoint' = ?", params[:endpoint]).first
+
+    @response[:status] = if found
+                           if found.failures >= 3
+                             :failed
+                           else
+                             :subscribed
+                           end
+                         else
+                           :unsubscribed
+                         end
+    @response[:success] = true
+  end
+
   def subscribe
     WebPushSubscription.create!(
       user:         current_user,

config/routes.rb

@@ -135,6 +135,7 @@ Rails.application.routes.draw do
     post "/subscribe", to: "subscription#subscribe", as: :subscribe_answer
     post "/unsubscribe", to: "subscription#unsubscribe", as: :unsubscribe_answer
     get "/webpush/key", to: "web_push#key", as: :webpush_key
+    post "/webpush/check", to: "web_push#check", as: :webpush_check
     post "/webpush", to: "web_push#subscribe", as: :webpush_subscribe
     delete "/webpush", to: "web_push#unsubscribe", as: :webpush_unsubscribe
   end