RdfJSONParser: Disable Date Parsing in Newtonsoft.JSON parser

[kal]

The RdfJsonParser class does not properly handle the case of a literal string that is formatted as an ISO 8601 date/time string. This code:

using VDS.RDF;
 using VDS.RDF.Parsing;
 ...
 var jsonstr = @"
 {
  ""http://example.com"": {
    ""http://purl.org/dc/terms/issued"": [{
        ""datatype"": ""http://www.w3.org/2001/XMLSchema#date"",
        ""type"": ""literal"",
        ""value"": ""2017-10-24T15:01:53+02:00""
      }]
    }
  }";

  IGraph g = new Graph();
  g.LoadFromString(str1, new RdfJsonParser());

Leads to the following exception:

Exception has occurred: CLR/VDS.RDF.Parsing.RdfParseException
Exception thrown: 'VDS.RDF.Parsing.RdfParseException' in dotNetRDF.dll: '[Line 4 Column 40 to Line 7 Column 44] Unexpected Token 'Date' encountered, expected a Property Value describing one of the properties of an Object Node'
   at VDS.RDF.Parsing.RdfJsonParser.Error(JsonParserContext context, String message, PositionInfo startPos)
   at VDS.RDF.Parsing.RdfJsonParser.ParseObject(JsonParserContext context, INode subj, INode pred)
   at VDS.RDF.Parsing.RdfJsonParser.ParseObjectList(JsonParserContext context, INode subj, INode pred)
   at VDS.RDF.Parsing.RdfJsonParser.ParsePredicateObjectList(JsonParserContext context, INode subj)
   at VDS.RDF.Parsing.RdfJsonParser.ParseTriples(JsonParserContext context)
   at VDS.RDF.Parsing.RdfJsonParser.ParseGraphObject(JsonParserContext context)
   at VDS.RDF.Parsing.RdfJsonParser.Parse(IRdfHandler handler, TextReader input)
   at VDS.RDF.Parsing.RdfJsonParser.Load(IRdfHandler handler, TextReader input)
   at VDS.RDF.Parsing.StringParser.Parse(IGraph g, String data, IRdfReader reader)

This appears to be because the underlying Newtonsoft.JSON parser has converted the ISO 8601 date string in the value property into a C# Date object, and our RdfJsonParser only expects string values.

This behaviour of the Newstonsoft parser can be disabled via the DateParseHandling property on the parser (by setting the property value to DateParseHandling.None).

Originally reported via this SO question

[pkanavos]

Perhaps the easiest way to do this would be to set

DateParseHandling= DateParseHandling.None;

in CommentIgnoringJsonTextReader's constructors