browser caching (TrilonIO#542)

closes TrilonIO#541

Author: hakonamatata

Startup.cs

@@ -9,6 +9,8 @@
 using Microsoft.EntityFrameworkCore;
 using AspCoreServer.Data;
 using Swashbuckle.AspNetCore.Swagger;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Net.Http.Headers;
 
 namespace AspCoreServer
 {
@@ -64,7 +66,30 @@ public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerF
       loggerFactory.AddConsole(Configuration.GetSection("Logging"));
       loggerFactory.AddDebug();
 
-      app.UseStaticFiles();
+      // app.UseStaticFiles();
+
+      app.UseStaticFiles(new StaticFileOptions()
+      {
+        OnPrepareResponse = c =>
+        {
+          //Do not add cache to json files. We need to have new versions when we add new translations.
+
+          if (!c.Context.Request.Path.Value.Contains(".json"))
+          {
+            c.Context.Response.GetTypedHeaders().CacheControl = new CacheControlHeaderValue()
+            {
+              MaxAge = TimeSpan.FromDays(30) // Cache everything except json for 30 days
+            };
+          }
+          else
+          {
+            c.Context.Response.GetTypedHeaders().CacheControl = new CacheControlHeaderValue()
+            {
+              MaxAge = TimeSpan.FromMinutes(15) // Cache json for 15 minutes
+            };
+          }
+        }
+      });
 
       DbInitializer.Initialize(context);