Forum Xamarin.iOS

WebRequest.Create(Uri uri) throws System.NotSupportedException: The URI prefix is not recognized.

XavierFortinXavierFortin USMember ✭✭
edited February 2017 in Xamarin.iOS

I'm in the Stable channel and I updated today (from mono 4.6.2 to 4.8.0, I didn't take note of the Xamarin.Mac and Xamarin Studio previous versions, but they were at the previous instances of the Stable channel). Since this update, I'm getting this exception (in the title) on every WebRequest.Create(Uri uri). By the way, the prefix is http.

The weirdest thing is that if I include the Mono runtime in the application bundle, this issue disappears.

I still wanted to find another workaround. So I did play around a bit and tried registering the prefix directly with this quite unappealing but somewhat functioning code:

Type httpRequestCreatorType = Assembly.GetAssembly(typeof(WebRequest)).GetTypes().FirstOrDefault(t => t.FullName == "System.Net.HttpRequestCreator");
IWebRequestCreate httpWebRequestCreate = (IWebRequestCreate)FormatterServices.GetUninitializedObject(httpRequestCreatorType);
WebRequest.RegisterPrefix("http", httpWebRequestCreate);

It does go through the WebRequest.Create without throwing an exception, only to throw the following exception on the HttpWebRequest.GetResponse:

System.NullReferenceException: Object reference not set to an instance of an object
  at System.Net.HttpWebRequest.EndGetResponse (System.IAsyncResult asyncResult) [0x0005e] in /private/tmp/source-mono-4.8.0/bockbuild-mono-4.8.0-branch/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/System/System.Net/HttpWebRequest.cs:1029 
  at System.Net.HttpWebRequest.GetResponse () [0x0000e] in /private/tmp/source-mono-4.8.0/bockbuild-mono-4.8.0-branch/profiles/mono-mac-xamarin/build-root/mono-x86/mcs/class/System/System.Net/HttpWebRequest.cs:1043

This is when I realized I was wasting my time and Including the Mono runtime would make for an acceptable workaround, since we were not including the Mono runtime only on debug build.

Still, I'm letting this here in case anyone has the time to look into this.


Best Answer


  • XavierFortinXavierFortin USMember ✭✭

    Then you will be please to hear that I am currently working on porting to Unified. :)

    But as mentioned, it caused some issues and because of the random nature of some of those issues, nearly everything requires extensive testing, which is extremely time consuming. I should see the end of it someday, though.

    Thank you for your quick answer.

  • ChrisHamonsChrisHamons USForum Administrator, Xamarin Team Xamurai

    Awesome. :smile:

    Porting large application, in particular ones with non-trivial GUIs, can be challenging. Best of luck o/

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