using System;

using System.Collections.Generic;

using System.Text;

using System.Linq;

using System.Xml.Serialization;

using System.Xml;

using System.Xml.Linq;

using System.Xml.Schema;

using System.IO;

using System.Reflection;

​

using NUnit.Framework; //NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/66126110/xml-to-object-using-xml-and-dtd

    [XmlRoot(ElementName="report", Namespace="http://tempuri.org/report")]

    public class report 

    {

        [XmlAttribute(AttributeName="details")]

        public string Details { get; set; }

    }

​

    public class TestClass

    {

        public static void Test()

        {

            var filename = "Question66126110.xml";

            try

            {

                File.WriteAllText(filename, GetXml());

​

                var report = XmlSerializationHelper.LoadFromXmlWithDTD<report>(filename, validationCallBack: ValidationCallBack);

                Console.WriteLine(report.Details);

                Assert.AreEqual("Something is described blablabla", report.Details);

            }

            finally

            {

                File.Delete(filename);

            }           

        }

        private static void ValidationCallBack(object sender, ValidationEventArgs e)

        {

            if (e.Severity == XmlSeverityType.Warning)

                Console.WriteLine("Warning: Matching schema not found.  No validation occurred." + e.Message);

            else // Error

                Console.WriteLine("Validation error: " + e.Message);

        }       

        static string GetXml()

        {

            return @"<?xml version=""1.0""?>

<!DOCTYPE report SYSTEM ""01.dtd"" [

    <!ENTITY parameter ""blablabla""> 

]>

​

<report xmlns=""http://tempuri.org/report""

  details=""Something is described &parameter;""

></report>

";

        }

    }

​

    public static partial class XmlSerializationHelper

    {

        public static T LoadFromXmlWithDTD<T>(string filename, XmlSerializer serial = default, ValidationEventHandler validationCallBack = default)

        {

            var settings = new XmlReaderSettings

            {

                // This will throw an exception if uncommented:

                //   System.Xml.XmlException: An error has occurred while opening external DTD 'file:///app/01.dtd': Could not find file '/app/01.dtd'

                // XmlResolver = new XmlUrlResolver(), 

                DtdProcessing = DtdProcessing.Parse,

                IgnoreWhitespace = true,

            };

            settings.ValidationEventHandler += validationCallBack;

            serial = serial ?? new XmlSerializer(typeof(T));

            using (var reader = XmlReader.Create(filename, settings))

                return (T)serial.Deserialize(reader);

        }

    }

​

    public static partial class XmlSerializationHelper

    {

        public static T ParseFromXmlWithDTD<T>(this string xmlString, XmlSerializer serial = null, ValidationEventHandler validationCallBack = default)

        {

            var settings = new XmlReaderSettings

            {

                // This will throw an exception if uncommented:

                //   System.Xml.XmlException: An error has occurred while opening external DTD 'file:///app/01.dtd': Could not find file '/app/01.dtd'

                // XmlResolver = new XmlUrlResolver(), 

                DtdProcessing = DtdProcessing.Parse,

                IgnoreWhitespace = true,

            };

            settings.ValidationEventHandler += validationCallBack;

            serial = serial ?? new XmlSerializer(typeof(T));

            using (var reader = XmlReader.Create(new StringReader(xmlString), settings))

                return (T)serial.Deserialize(reader);

        }

​

        public static T ParseFromXml<T>(this string xmlString, XmlSerializer serial = null)

        {

            serial = serial ?? new XmlSerializer(typeof(T));

            using (var reader = new StringReader(xmlString))

            {

                return (T)serial.Deserialize(reader);

            }

        }

​

        public static string GetXml<T>(this T obj, XmlSerializer serializer = null, bool omitStandardNamespaces = false)

        {

            XmlSerializerNamespaces ns = null;

            if (omitStandardNamespaces)

            {

                ns = new XmlSerializerNamespaces();

                ns.Add("", ""); // Disable the xmlns:xsi and xmlns:xsd lines.

            }           

            using (var textWriter = new StringWriter())

            {

                var settings = new XmlWriterSettings() { Indent = true }; // For cosmetic purposes.

                using (var xmlWriter = XmlWriter.Create(textWriter, settings))

                    (serializer ?? new XmlSerializer(obj.GetType())).Serialize(xmlWriter, obj, ns);

                return textWriter.ToString();

            }

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1})", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , GetNetCoreVersion());

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

        public static string GetNetCoreVersion()

        {

            //https://techblog.dorogin.com/how-to-detect-net-core-version-in-runtime-ecd65ad695be

            //

            var assembly = typeof(System.Runtime.GCSettings).GetTypeInfo().Assembly;

            var assemblyPath = assembly.CodeBase.Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);

            int netCoreAppIndex = Array.IndexOf(assemblyPath, "Microsoft.NETCore.App");

            if (netCoreAppIndex > 0 && netCoreAppIndex < assemblyPath.Length - 2)

                return assemblyPath[netCoreAppIndex + 1];

            return null;

        }

    }

​