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.IO;

using System.Data;

using System.Runtime.Serialization;

using System.Runtime.Serialization.Formatters.Binary;

using System.IO.Compression;

using System.Reflection;

using System.Text.RegularExpressions;

​

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

​

    //https://stackoverflow.com/questions/58692275/c-sharp-net-is-there-a-simple-way-of-querying-the-same-xml-node-over-a-collec

​

    public static partial class XmlReaderExtensions

    {

        /// <summary>

        /// Read all immediate child elements of the current element, and yield return a reader for those matching the incoming name & namespace.

        /// Leave the reader positioned after the end of the current element

        /// </summary>

        public static IEnumerable<XmlReader> ReadElements(this XmlReader inReader, string localName, string namespaceURI)

        {

            inReader.MoveToContent();

            if (inReader.NodeType != XmlNodeType.Element)

                throw new InvalidOperationException("The reader is not positioned on an element.");

            var isEmpty = inReader.IsEmptyElement;

            inReader.Read();

            if (isEmpty)

                yield break;

            while (!inReader.EOF)

            {

                switch (inReader.NodeType)

                {

                    case XmlNodeType.EndElement:

                        // Move the reader AFTER the end of the element

                        inReader.Read();

                        yield break;

                    case XmlNodeType.Element:

                        {

                            if (inReader.LocalName == localName && inReader.NamespaceURI == namespaceURI)

                            {

                                using (var subReader = inReader.ReadSubtree())

                                {

                                    subReader.MoveToContent();

                                    yield return subReader;

                                }

                                // ReadSubtree() leaves the reader positioned ON the end of the element, so read that also.

                                inReader.Read();

                            }

                            else

                            {

                                // Skip() leaves the reader positioned AFTER the end of the element.

                                inReader.Skip();

                            }

                        }

                        break;

                    default:

                        // Not an element: Text value, whitespace, comment.  Read it and move on.

                        inReader.Read();

                        break;

                }

            }

        }

​

        /// <summary>

        /// Read all immediate descendant elements of the current element, and yield return a reader for those matching the incoming name & namespace.

        /// Leave the reader positioned after the end of the current element

        /// </summary>

        public static IEnumerable<XmlReader> ReadDescendants(this XmlReader inReader, string localName, string namespaceURI)

        {

            inReader.MoveToContent();

            if (inReader.NodeType != XmlNodeType.Element)

                throw new InvalidOperationException("The reader is not positioned on an element.");

            using (var reader = inReader.ReadSubtree())

            {

                while (reader.ReadToFollowing(localName, namespaceURI))

                {

                    using (var subReader = inReader.ReadSubtree())

                    {

                        subReader.MoveToContent();

                        yield return subReader;

                    }

                }

            }

            // Move the reader AFTER the end of the element

            inReader.Read();

        }

    }

​

    class TestClass

    {

        public static void Test()

        {

            foreach (var xml in GetNestedXml())

                Test(xml);

        }

        const string fullFileName = "Question58692275.zip";

        static void Test(string inXml)

        {

            foreach (var xml in new[] { inXml, XDocument.Parse(inXml).ToString(SaveOptions.DisableFormatting), XDocument.Parse(inXml).ToString(SaveOptions.None) })

            {

                File.Delete(fullFileName);  

                using (var archive = ZipFile.Open(fullFileName, ZipArchiveMode.Create))

                {

                    var xmlFile = archive.CreateEntry("widgets1.xml");

​

                    using (var entryStream = xmlFile.Open())

                    using (var streamWriter = new StreamWriter(entryStream))

                    {

                        streamWriter.Write(xml);

                    }

                }               

                // zfft = et.parse(zff).getroot()

                // https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.ElementTree.getroot

​

                // zffts = zfft.findall('Widget')

                // Enumerate all immediate child nodes named "Widget" (recursive descent operator // was not used):

                // https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.Element.findall

​

                // wgt.find('Description').text

                // Finds the first subelement matching match and gets its text.

                // https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.Element.find

                // https://docs.python.org/3/library/xml.etree.elementtree.html#xml.etree.ElementTree.Element.text

​

                TestNestedReadElements(xml);

                TestNestedDescendants(xml);

            }

        }

​

        private static void TestNestedReadElements(string xml)

        {

            var zipListBox = new List<string>();

​

            using (var archive = ZipFile.Open(fullFileName, ZipArchiveMode.Read))

            {

                foreach (var entry in archive.Entries)

                {

                    if (Path.GetExtension(entry.Name).Equals(".xml", StringComparison.OrdinalIgnoreCase))

                    {

                        using (var zipEntryStream = entry.Open())

                            using (var reader = XmlReader.Create(zipEntryStream))

                        {

                            // Move to the root element

                            reader.MoveToContent();

​

                            var query = reader

                                // Read all child elements <Widgets>

                                .ReadElements("Widgets", "")

                                // Read all child elements <Widget>

                                .SelectMany(r => r.ReadElements("Widget", ""))

                                // And extract the text content of their first child element <Description>

                                .SelectMany(r => r.ReadElements("Description", "").Select(i => i.ReadElementContentAsString()).Take(1));

​

                            zipListBox.AddRange(query);

                        }

                    }

                }

            }

​

            zipListBox.Dump();

​

            Assert.IsTrue(Regex.Matches(xml, "My Description").Count == zipListBox.Count);

​

            using (var archive = ZipFile.Open(fullFileName, ZipArchiveMode.Read))

            {

                foreach (var entry in archive.Entries)

                {

                    if (Path.GetExtension(entry.Name).Equals(".xml", StringComparison.OrdinalIgnoreCase))

                    {

                        using (var zipEntryStream = entry.Open())

                            using (var reader = XmlReader.Create(zipEntryStream))

                        {

                            // Move to the root element

                            reader.MoveToContent();

​

                            var query = reader

                                // Read all child elements <Widgets>

                                .ReadElements("Widgets", "")

                                // Read all child elements <Widget>

                                .SelectMany(r => r.ReadElements("Widget", ""))

                                .Select(r => XElement.Load(r))

                                .Select(e => new { Description = e.Element("Description")?.Value, Id = e.Attribute("id")?.Value, Name = e.Element("Name")?.Value });

​

                            foreach (var widget in query)

                            {

                                Console.WriteLine("Id = {0}, Name = {1}, Description = {2}", widget.Id, widget.Name, widget.Description);

                            }

                        }

                    }

                }

            }

        }

        private static void TestNestedDescendants(string xml)

        {

            var zipListBox = new List<string>();

​

            using (var archive = ZipFile.Open(fullFileName, ZipArchiveMode.Read))

            {

                foreach (var entry in archive.Entries)

                {

                    if (Path.GetExtension(entry.Name).Equals(".xml", StringComparison.OrdinalIgnoreCase))

                    {

                        using (var zipEntryStream = entry.Open())

                            using (var reader = XmlReader.Create(zipEntryStream))

                        {

                            // Move to the root element

                            reader.MoveToContent();

​

                            var query = reader

                                // Read all descendant elements <Widget>

                                .ReadDescendants("Widget", "")

                                // And extract the text content of their first child element <Description>

                                .SelectMany(r => r.ReadElements("Description", "").Select(i => i.ReadElementContentAsString()).Take(1));

​

                            zipListBox.AddRange(query);

                        }

                    }

                }

            }

​

            zipListBox.Dump();

​

            Assert.IsTrue(Regex.Matches(xml, "My Description").Count == zipListBox.Count);

​

            using (var archive = ZipFile.Open(fullFileName, ZipArchiveMode.Read))

            {

                foreach (var entry in archive.Entries)

                {

                    if (Path.GetExtension(entry.Name).Equals(".xml", StringComparison.OrdinalIgnoreCase))

                    {

                        using (var zipEntryStream = entry.Open())

                            using (var reader = XmlReader.Create(zipEntryStream))

                        {

                            // Move to the root element

                            reader.MoveToContent();

​

                            var query = reader

                                // Read all descendant elements <Widget>

                                .ReadDescendants("Widget", "")

                                // And extract the text content of their first child element <Description>

                                .Select(r => XElement.Load(r))

                                .Select(e => new { Description = e.Element("Description")?.Value, Id = e.Attribute("id")?.Value, Name = e.Element("Name")?.Value });

​

                            foreach (var widget in query)

                            {

                                Console.WriteLine("Id = {0}, Name = {1}, Description = {2}", widget.Id, widget.Name, widget.Description);

                            }

                        }

                    }

                }

            }       

        }

        static IEnumerable<string> GetNestedXml()

        {

            return GetXml().Select(s => "<Document>" + s + "</Document>");

        }

        static IEnumerable<string> GetXml()

        {

            var xml = new[] {

@"<Widgets />",

@"<Widgets><Widget /></Widgets>",

@"<Widgets>

  <Widget id=""0""><!--Comment-->

    <Description>My Description</Description>

    <Bar><Foo>Description</Foo></Bar>

  </Widget>

  <Widget id=""1""/>

  <Widget id=""2""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar>

  </Widget>

  <NotAWidget id=""x"">

  </NotAWidget>

  <NotAWidget id=""x""/><Widget id=""0""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar></Widget><Widget id=""1""/><Widget id=""2""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar></Widget><NotAWidget id=""x""></NotAWidget><NotAWidget id=""x""/>

  <Widget id=""0""><!--Comment-->

    <Description>My Description</Description>

    <Bar><Foo>Description</Foo></Bar>

  </Widget>

  <Widget id=""1""/>

  <Widget id=""2""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar>

  </Widget>

  <NotAWidget id=""x"">

  </NotAWidget>

  <NotAWidget id=""x""/><Widget id=""0""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar></Widget><Widget id=""1""/><Widget id=""2""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar></Widget><NotAWidget id=""x""></NotAWidget><NotAWidget id=""x""/><Widget id=""0""><!--Comment-->

    <Description>My Description</Description>

    <Bar><Foo>Description</Foo></Bar>

  </Widget><Widget id=""1""/>

  <Widget id=""2""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar>

  </Widget>

  <NotAWidget id=""x"">

  </NotAWidget><NotAWidget id=""x""/><Widget id=""0""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar></Widget><Widget id=""1""/><Widget id=""2""><Description>My Description</Description><Bar><Foo>Description</Foo></Bar></Widget><NotAWidget id=""x""></NotAWidget><NotAWidget id=""x""/>

</Widgets>

" };

            return xml;

        }

    }

    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;

        }

    }

​