Use IRequiresSessionState Interface to access Session data in custom HTTP Handler.
IRequiresSessionState Interface is just marker to indicate that a specified custom HTTP Handler can read and write session state values. Since, it is a marker interace there won't be any methods to be implemented.
Syntax:
public class MyHandler : IHttpHandler,IRequiresSessionState
{
processRequest(HttpContext context)
{
//Now,Session Can be accessed.
context.Session["id"]="test";
}
}
Similar way,we can use IReadOnlySessionState marker Interface to have read only permission on Session data.Without specifying above markers, Session will be null in our Custom HTTP Handler.