questions/47881189/xml-entities-in-json-net

CSharp · Console

/Program.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.Serialization.Formatters;
using System.IO;
using System.Data;
using System.ComponentModel.DataAnnotations;
using System.Globalization;
using System.Xml;
using System.Xml.Linq;

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using Newtonsoft.Json.Converters;
using Newtonsoft.Json.Serialization;	

    // https://stackoverflow.com/questions/47881189/xml-entities-in-json-net
    class TestClass
    {
        public static void Test()
        {
            string xml = @"<?xml version='1.0' standalone='no'?>
    <!DOCTYPE notes [
        <!ENTITY ent 'Sample text'>
    ]>
    <notes>
        <note>&ent;</note>
    </notes>";

            var json2 = Test2(xml);
            var json1 = Test1(xml);
			
			Assert.IsTrue(json2 == json1);
			
			Console.WriteLine("\nXDocument and XmlDocument produce identical results.");
        }

        private static string Test2(string xml)
        {
            Console.WriteLine("\nTesting XDocument...");
            var doc = XDocument.Parse(xml);
            string json = JsonConvert.SerializeXNode(doc, Newtonsoft.Json.Formatting.Indented);
            Console.WriteLine(json);
			
			return json;
        }

        private static string Test1(string xml)
        {
            Console.WriteLine("\nTesting XmlDocument...");


			var settings = new XmlReaderSettings
			{
				// Allow processing of DTD
				DtdProcessing = DtdProcessing.Parse,
				// On older versions of .Net instead set 
				//ProhibitDtd = false,
				// But for security, prevent DOS attacks by limiting the total number of characters that can be expanded to something sane.
				MaxCharactersFromEntities = (long)1e7,
				// And for security, disable resolution of entities from external documents.
				XmlResolver = null,
			};
            XmlDocument doc = new XmlDocument();
            using (var textReader = new StringReader(xml))
            using (var xmlReader = XmlReader.Create(textReader, settings))
            {
                doc.Load(xmlReader);
            }
            string json = JsonConvert.SerializeXmlNode(doc, Newtonsoft.Json.Formatting.Indented);
            Console.WriteLine(json);
			
			return json;
        }
    }
	public class Program
	{
		public static void Main()
		{
			Console.WriteLine("Environment version: " + Environment.Version);
			Console.WriteLine("Json.NET version: " + typeof(JsonSerializer).Assembly.FullName);
			Console.WriteLine();

			try
			{
				TestClass.Test();
			}
			catch (Exception ex)
			{
				Console.WriteLine("Failed with unhandled exception: ");
				Console.WriteLine(ex);
				throw;
			}
		}
	}

    public class AssertionFailedException : System.Exception
    {
        public AssertionFailedException() : base() { }

        public AssertionFailedException(string s) : base(s) { }
    }

    public static class Assert
    {
        public static void IsTrue(bool value)
        {
            IsTrue(value, "failed");
        }

        public static void IsTrue(bool value, string message)
        {
            if (value == false)
                throw new AssertionFailedException(message ?? "failed");
        }
    }