How to cache data in a MVC application

Question

I have read lots of information about page caching and partial page caching in a MVC application. However, I would like to know how you would cache data.

In my scenario I will be using LINQ to Entities (entity framework). On the first call to GetNames (or whatever the method is) I want to grab the data from the database. I want to save the results in cache and on the second call to use the cached version if it exists.

Can anyone show an example of how this would work, where this should be implemented (model?) and if it would work.

I have seen this done in traditional ASP.NET apps , typically for very static data.

Answer 1

Reference the System.Web dll in your model and use System.Web.Caching.Cache

public string[] GetNames()
{
  if(Cache["names"] == null)
  {
    Cache["names"] = DB.GetNames();
  }
  return (string[])Cache["names"];
}

A bit simplified but I guess that would work. This is not MVC specific and I have always used this method for caching data.

Answer 2

Here's nice Cache service I use:

public class InMemoryCache: ICacheService
{
public T Get<T>(string cacheID, Func<T> getItemCallback) where T : class
{
    T item = HttpRuntime.Cache.Get(cacheID) as T;
    if (item == null)
    {
        item = getItemCallback();
        HttpContext.Current.Cache.Insert(cacheID,item);
    }
    return item;
}
}

ICacheService has just one Get() method defined.

You use it like this:
cacheProvider.Get("cache id", (delegate method if cache is empty));
So, Cache provider will check if there's anything by "cache id" in cache, and if there's not, it will call delegate method to fetch data and store it in cache.

Realworld example:

var products=cacheService.Get("catalog.products", ()=>productRepository.GetAll())

Answer 3

You can also try and use the caching built into ASP MVC:

Add the following attribute to the controller method you'd like to cache:

[OutputCache(Duration=10)]

In this case the ActionResult of this will be cached for 10 seconds.

More on this here

Answer 4

I'm referring to TT's post and suggest the following approach:

Reference the System.Web dll in your model and use System.Web.Caching.Cache

public string[] GetNames()
{ 
    var noms = Cache["names"];
    if(noms == null) 
    {    
        noms = DB.GetNames();
        Cache["names"] = noms; 
    }

    return ((string[])noms);
}

You should not return a value read from the cache, since you'll never know if at that specific moment it is still in the cache. Even if you inserted it in the statement before, it might already be gone or has never been addred to the cache - you just don't know.

Answer 5

I have tried this code block in my model after adding System.Web.Caching

var noms = Cache["names"];
    if(noms == null) 
    {    
        noms = DB.GetNames();
        Cache["names"] = noms; 
    }

And on compilation getting error 'System.Web.Caching.Cache' is a 'type' but is used like a 'variable'