Asp.net Mvc - Kigg: Maintain User object in HttpContext.Items between requests.
- by Pickels
Hallo,
first I want to say that I hope this doesn't look like I am lazy but I have some trouble understanding a piece of code from the following project.
http://kigg.codeplex.com/
I was going through the source code and I noticed something that would be usefull for my own little project I am making. In their BaseController they have the following code:
private static readonly Type CurrentUserKey = typeof(IUser);
public IUser CurrentUser
{
get
{
if (!string.IsNullOrEmpty(CurrentUserName))
{
IUser user = HttpContext.Items[CurrentUserKey] as IUser;
if (user == null)
{
user = AccountRepository.FindByClaim(CurrentUserName);
if (user != null)
{
HttpContext.Items[CurrentUserKey] = user;
}
}
return user;
}
return null;
}
}
This isn't an exact copy of the code I adjusted it a little to my needs. This part of the code I still understand. They store their IUser in HttpContext.Items. I guess they do it so that they don't have to call the database eachtime they need the User object.
The part that I don't understand is how they maintain this object in between requests. If I understand correctly the HttpContext.Items is a per request cache storage.
So after some more digging I found the following code.
internal static IDictionary<UnityPerWebRequestLifetimeManager, object> GetInstances(HttpContextBase httpContext)
{
IDictionary<UnityPerWebRequestLifetimeManager, object> instances;
if (httpContext.Items.Contains(Key))
{
instances = (IDictionary<UnityPerWebRequestLifetimeManager, object>) httpContext.Items[Key];
}
else
{
lock (httpContext.Items)
{
if (httpContext.Items.Contains(Key))
{
instances = (IDictionary<UnityPerWebRequestLifetimeManager, object>) httpContext.Items[Key];
}
else
{
instances = new Dictionary<UnityPerWebRequestLifetimeManager, object>();
httpContext.Items.Add(Key, instances);
}
}
}
return instances;
}
This is the part where some magic happens that I don't understand. I think they use Unity to do some dependency injection on each request? In my project I am using Ninject and I am wondering how I can get the same result.
I guess InRequestScope in Ninject is the same as UnityPerWebRequestLifetimeManager? I am also wondering which class/method they are binding to which interface? Since the HttpContext.Items get destroyed each request how do they prevent losing their user object?
Anyway it's kinda a long question so I am gradefull for any push in the right direction.
Kind regards,
Pickels
