ASP .Net MVC 5 JsonResult caching - json

Question

can someone explain me how to implement caching of JsonResult actions in MVC 5 application?
I want to use caching of some ajax-called actions using [OutputCache()] attribute. Some of these actions return ActionResult with html-content, some JsonResult with serialized lists of {Id, Title} pairs which I'm going to use to construct dropdown lists.
My goal is to reduce amount of DB-queries (while building ViewModels) and server requests (when using ajax-calls for it).
So, my code looks like snippets below:
[OutputCache(Duration=60*60*24)]
public async Task<ActionResult> SearchCaseOrgDialog(){
//extract data return html page
return View();
}
[OutputCache(Duration=60*60*24)]
public async Task<JsonResult> AjaxOrgDepartments(){
//query database, serialize data, return json
var result = await ctx.OrgDepartments
.Select(d => new {
Id = d.Id,
Title = d.Title }
)
.ToListAsync();
return Json(result, JsonRequestBehavior.AllowGet);
}
When I look at FireFox tools-panel I see next picture for Html-content:
Here Firefox uses client-side cached version of ajax-requested page.
But situation differs with json-content:
It doesn't cache content, and seems to transfer data from server (server-side cache).
In both cases response headers look the same:
Cache-Control:"public, max-age=86400, s-maxage=0"
Content is requested using similar ajax-calls like
$.get(url, null, function(data){
//do something with data
});
So, how do I cache json-content? what is the right way to do it, and why default approach does not work?

Answer 1

If you want to avoid DB queries, you should consider caching the data at server side. You can use MemoryCache class to do that.
Quick sample
public class MyLookupDataCache
{
const string categoryCacheKey = "CATEGORYLIST";
public List<string> GetCategories()
{
var cache = MemoryCache.Default;
var items = cache.Get(categoryCacheKey);
if (items != null)
{
CacheItemPolicy policy = new CacheItemPolicy();
policy.AbsoluteExpiration = DateTime.Now.AddDays(7); //7 days
//Now query from db
List<string> newItems = repository.GetCategories();
cache.Set(categoryCacheKey, newItems, policy);
return newItems;
}
else
{
return (List<string>) items;
}
}
}
You can change the method signature to return the type you want. For simplicity, i am using List<String>