JSON parsing result for friends list or batching fails on UWP app

Whenever I use the SDK for a UWP app, calling to get a friends list and/or making a batch call leads to JSON deserialization exception. This is likely due to these lines in FacebookClient.cs ~Line 614:

#if !(SILVERLIGHT || NETFX_CORE)
            request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
            request.AllowWriteStreamBuffering = false;
#endif
#if NETFX_CORE
            request.Headers[HttpRequestHeader.AcceptEncoding] = "gzip,deflate";
#endif

The problem here is that this code prevents automatic decompression but tells FB that it accepts compressed results.

I was able to get around this by overriding the HttpWebRequestWrapper and setting the web request factory to return that wrapper. In the TrySetUserAgent, I then clear the accept.

    public class MyHttpWebRequestWrapper : HttpWebRequestWrapper
    {
        public MyHttpWebRequestWrapper(HttpWebRequest request) : base(request)
        {
        }
        public override bool TrySetUserAgent(string userAgent)
        {
            this.Headers[HttpRequestHeader.AcceptEncoding] = "";
            return base.TrySetUserAgent(userAgent);
        }
    }

I could use the deserializationn handler to see that the results were not text let alone JSON. Fought with this for hours…

[MrAndrewAu]

For me, the SDK has recently stopped working in my Windows 10 Universal Project. Requests throw the “Invalid JSON” exception as the results looked like gibberish. I think we are experiencing the same problem.

However, the SDK still works fine in my Windows 8.1 project. I encountered a similar situation recently with the Twitter SDK where web requests worked in a Windows 8.1 project but not in a Windows 10 project, and it was because Windows 10 apps enforce HTTP/2 protocol (instead of HTTP/1.1). This caused things to break, despite Microsoft’s promise that nothing needs to be changed after the update.

It looks like we have to enforce protocol to HTTP/1.1, but the problem is that System.Net.HttpWebRequest in .NET Core doesn’t have a definition for ProtocolVersion.

[AndyDragon]

Here is the code to create and prepare the client:

        public static FacebookClient CreateClient()
        {
            var client = new FacebookClient(Session.ActiveSession.CurrentAccessTokenData.AccessToken);
            client.SetHttpWebRequestFactory(uri => {
                var request = new MyHttpWebRequestWrapper((HttpWebRequest)WebRequest.Create(uri));
                return request;
            });
            return client;
        }