Allow for cancelling downloads from filesystem

Rebuild request orignally will use setting for constructing the url
Rebuild request from client via no-cache will use httppcontext to get runtime pathing to generate url
Escape the url generated

TinfoilVibeServerTest/Tests/BasicAuthMiddlewareTests.cs

@@ -31,7 +31,7 @@ namespace TinfoilVibeServerTest.Tests
             _middleware = new BasicAuthMiddleware(_next);
         }
 
-        private HttpContext CreateContext(string authHeader = null, string ip = "127.0.0.1", int? uid = null)
+        private HttpContext CreateContext(string authHeader = "", string ip = "127.0.0.1", int? uid = null)
         {
             var ctx = new DefaultHttpContext();
             ctx.Connection.RemoteIpAddress = IPAddress.Parse(ip);