Question

I have an application where each user can choose a custom layout. The layouts can be different and it’s not just css styles but html as well.

I know that mvc would cache the layout, but having so many layouts I doubt it would fit in cache. So what would it be better to save templates in DB or on the disk?

FYI: DB that I’m using is MongoDB.

Answer 1

I would save the layouts on disk because at the moment I don’t see any advantage in a database (unless you do). But one thing that is worth mentioning is that you can create a class derived from OutputCacheAttribute and have your saved result depend on the layout you’re using.

Does the layout depend on user? You could use the VaryByCustom property to have it vary by user.

EDIT

Are your users allowed to change layouts dinamically? If yes, you should also have a guid associated to your users change it each time the layouts change so you return on your VaryByCustom method:

return string.Format("User-{0}-{1}", user.Id, user.LayoutUpdateGuid);

See the meaning of this? This way, when a user changes the layouts, they will see their pages updated immediately.

How to apply the VaryByCustom attribute in your situation

In your action method, you may use:

[OutputCache(Duration = 3600, VaryByCustom = "UserLayouts")]
public ActionResult Details(string param)
{
   // Returning the view
}

Then, in your VaryByCustom method in your Global.asax.cs file:

protected override string VaryByCustom(string custom)
{
  switch (custom)
  {
    case "UserLayouts":
      //// Here you fetch your user details so you can return a unique
      //// string for each user and "publishing cycle" 
      //// Also, I strongly suggest you cache this user object and expire it
      //// whenever the user is changed (e.g. when the LayoutUpdateGuid is
      //// changed) so you achieve maximum speed and not defeat the purpose
      //// of using output cache.
      return string.Format("User-{0}-{1}", user.Id, user.LayoutUpdateGuid);
    break;
  }
}

The missing piece

The missing piece here is that you need to store a value that I called LayoutUpdateGuid (I’m sure you’ll find a better name) and change that value whenever a user changes his layouts => this will lead to a different string being returned by the VaryByCustom(string) method in the Global.asasx.cs which in turn will force your action method to run again and return the result with the updated layout.

Makes sense to you?

Note: I can’t test the specific code I wrote here, but I am sure (apart from typos) it is correct.