How do I force a relative URI to use https?

Question

I have a relative URI:

Uri U = new Uri("../Services/Authenticated/VariationsService.svc", 
                               UriKind.Relative);

The problem is that depending on whether the user has typed https:// or http:// into their web browser to get to the silverlight application, it may use either http or https when trying to contact the service.

I want to force the program to use https for connecting to the service eitherway.

Initially I tried this:

            Uri U = new Uri("../Services/Authenticated/VariationsService.svc", 
                               UriKind.Relative);

            string NU = U.AbsoluteUri;

            U = new Uri(NU.Replace("http://", "https://"), UriKind.Absolute);

But it fails at U.AbsoluteUri because it can't convert the relative Uri into an absolute Uri at that stage. So how do I change the Uri Scheme to https?

Answer 1

The protocol is a separate component, so I think that you can just put it in front of your relative address:

Uri U = new Uri("https:../Services/Authenticated/VariationsService.svc", UriKind.Relative);

Answer 2

"Scheme" does not have any meaning in a relative URI. You'll have to convert it to an absolute URI at some point to change the scheme.

Answer 3

The relative path has to be converted to absolute first. I do that using the Uri of the excuting Silverlight XAP file.

There might be ways to reduce this a bit (it feels wrong doing string operations with Uris) but it's a start:

    // Get the executing XAP Uri
    var appUri = App.Current.Host.Source;

    // Remove the XAP filename
    var appPath = appUri.AbsolutePath.Substring(0, appUri.AbsolutePath.LastIndexOf('/'));

    // Construct the required absolute path
    var rootPath = string.Format("https://{0}{1}", appUri.DnsSafeHost, appUri.AbsolutePath);

    // Make the relative target Uri absolute (relative to the target Uri)
    var uri = new Uri(new Uri(rootPath), "../Services/Authenticated/VariationsService.svc");

This does not include transferring a portnumber (which you might want to do in other circumstance). Personally I would put the above code in a helper method that also handles the port (and whatever you want to do differently when running localhost).

Hope this helps.

Answer 4

Instead, you should change your ASPX file which hosts your silverlight, and force user to redirect to SSL only if he/she is logged in using non SSL url. Because ideally it would be perfect if silverlight opens connection only to the same domain and scheme it loaded from.