Plugin Base WebViewPage #22 & Authorization #24

Plugins have a base WebViewPage to inherit, this offers integration with
various Disco services. Plugins can also add Authorization attributes to
their Web Handlers and Controller Methods.

Disco.Services/Authorization/DiscoAuthorizeBaseAttribute.cs

@@ -0,0 +1,39 @@
+using Disco.Services.Users;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Web.Mvc;
+
+namespace Disco.Services.Authorization
+{
+    public abstract class DiscoAuthorizeBaseAttribute : AuthorizeAttribute
+    {
+        protected AuthorizationToken Token
+        {
+            get
+            {
+                return UserService.CurrentAuthorization;
+            }
+        }
+
+        public abstract bool IsAuthorized(System.Web.HttpContextBase httpContext);
+        public abstract string HandleUnauthorizedMessage();
+
+        protected sealed override bool AuthorizeCore(System.Web.HttpContextBase httpContext)
+        {
+            if (httpContext == null)
+                throw new ArgumentNullException("httpContext");
+
+            return IsAuthorized(httpContext);
+        }
+
+        protected sealed override void HandleUnauthorizedRequest(AuthorizationContext filterContext)
+        {
+            string resultMessage = HandleUnauthorizedMessage();
+
+            filterContext.Result = new HttpUnauthorizedResult(resultMessage);
+        }
+    }
+}