RESTSharp has problems deserializing XML including Byte Order Mark?

Question

There is a public webservice which I want to use in a short C# Application: http://ws.parlament.ch/

The returned XML from this webservice has a "BOM" at the beginning, which causes RESTSharp to fail the deserializing of the XML with the following error message:

Error retrieving response. Check inner details for more info. ---> System.Xml.XmlException: Data at the root level is invalid. Line 1, position 1. at System.Xml.XmlTextReaderImpl.Throw(Exception e)
at System.Xml.XmlTextReaderImpl.Throw(String res, String arg) at System.Xml.XmlTextReaderImpl.ParseRootLevelWhitespace() at System.Xml.XmlTextReaderImpl.ParseDocumentContent() at System.Xml.XmlTextReaderImpl.Read() at System.Xml.Linq.XDocument.Load(XmlReader reader, LoadOptions options) at System.Xml.Linq.XDocument.Parse(String text, LoadOptions options)
at System.Xml.Linq.XDocument.Parse(String text) at RestSharp.Deserializers.XmlDeserializer.Deserialize[T](IRestResponse response) at RestSharp.RestClient.Deserialize[T](IRestRequest request, IRestResponse raw)
--- End of inner exception stack trace ---

Here is an easy sample by using http://ws.parlament.ch/sessions?format=xml to get a List of 'Sessions':

public class Session
{
    public int Id { get; set; }
    public DateTime? Updated { get; set; }
    public int? Code { get; set; }
    public DateTime? From { get; set; }
    public string Name { get; set; }
    public DateTime? To { get; set; }
}


static void Main(string[] args)
    {
        var request = new RestRequest();
        request.RequestFormat = DataFormat.Xml;
        request.Resource = "sessions";
        request.AddParameter("format", "xml");

        var client = new RestClient("http://ws.parlament.ch/");
        var response = client.Execute<List<Session>>(request);

        if (response.ErrorException != null)
        {
            const string message = "Error retrieving response.  Check inner details for more info.";
            var ex = new ApplicationException(message, response.ErrorException);
            Console.WriteLine(ex);
        }

        List<Session> test = response.Data;

        Console.Read();
    }

When I first manipulate the returned xml with Fiddler to remove the first 3 bits (the "BOM"), the above code works! May someone please help me to handle this directly in RESTSharp? What am I doing wrong? THANK YOU in advance!

Answer 1

I found the Solution - Thank you @arootbeer for the hints!

Instead of wrapping the XMLDeserializer, you can also use the 'RestRequest.OnBeforeDeserialization' event from #RESTSharp. So you just need to insert something like this after the new RestRequest() (see my initial code example) and then it works perfect!

request.OnBeforeDeserialization = resp =>
            {
                //remove the first ByteOrderMark
                //see: http://stackoverflow.com/questions/19663100/restsharp-has-problems-deserializing-xml-including-byte-order-mark
                string byteOrderMarkUtf8 = Encoding.UTF8.GetString(Encoding.UTF8.GetPreamble());
                if (resp.Content.StartsWith(byteOrderMarkUtf8))
                    resp.Content = resp.Content.Remove(0, byteOrderMarkUtf8.Length);
            };