In v3 we had "WixExtension" - how to upgrade extension to v5 or in which nuget this class exicts?

[vdrasutis]

Hello.
I had extension to get

using Microsoft.Tools.WindowsInstallerXml;

namespace MyWixFileVersionExtension
{
    public class MyWixFileVersionExtension : WixExtension
    {
        private MyWixFileVersionPreprocessorExtension _versionPreprocessorExtension;

        public override PreprocessorExtension PreprocessorExtension
        {
            get
            {
                // If we haven't created the preprocessor then do it now
                if (_versionPreprocessorExtension == null)
                    _versionPreprocessorExtension = new MyWixFileVersionPreprocessorExtension();

                // Return the preprocessor
                return _versionPreprocessorExtension;
            }
        }
    }
}

using System;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Reflection;
using Microsoft.Tools.WindowsInstallerXml;

namespace MyWixFileVersionExtension
{
    public class MyWixFileVersionPreprocessorExtension : PreprocessorExtension
    {
        private static readonly string[] prefixes = { "fileVersion" };

        public override string[] Prefixes
        {
            get { return prefixes; }
        }

        /// In case of parameter: <?define ProductVersion="$(fileVersion.ProductVersion($(var.MyOutputDirectory)\MyExecutable.exe))"?> 
        /// prefix can be equal to "fileVersion"
        /// function can be equal to "ProductVersion"
        /// args[0] can be equal to "..\..\..\Release\MyExecutable.exe"
        public override string EvaluateFunction(string prefix, string function, string[] args)
        {
            switch (prefix)
            {
                case "fileVersion":
                    // Make sure there actually is a file name
                    if (args.Length == 0 || args[0].Length == 0)
                        throw new ArgumentException("File name not specified");

                    // Make sure the file exists
                    if (!File.Exists(args[0]))
                        throw new ArgumentException(string.Format("File name {0} does not exist", args[0]));

                    // Get the file version information for the given file
                    var fileVersionInfo = FileVersionInfo.GetVersionInfo(args[0]);

                    // Get the property that matches the name of the function
                    var propertyInfo = fileVersionInfo.GetType().GetProperty(function);

                    // Make sure the property exists
                    if (propertyInfo == null) 
                    {
                        throw new ArgumentException(string.Format("Unable to find property {0} in FileVersionInfo", function));
                    }
                    
                    var result = propertyInfo.GetValue(fileVersionInfo, null).ToString();

                    if (!function.Contains("ProductVersion"))
                    {
                        return result;
                    }
                    var indexOfMinus = result.IndexOf('-');
                    
                    if (indexOfMinus > 0)
                    {
                        result = result.Remove(indexOfMinus - 1);
                    }

                    return result;
            }

            return null;
        }
    }
}

Then I am including it in teh wix project and defining property like this:

<Wix>
    <?define ProductVersion="$(fileVersion.ProductVersion($(var.MyOutputDirectory)\MyExecutable.exe))"?> 
    <Package Name="My App $(var.ProductVersion)" >
    ....
</Wix>

Question how I should upgrade/migrate this code to v4/v5 of WixToolset?
As I did not found anything about extension migration in Docs or internet :(.

For the Preprocessor class as I understand it should look like below (use 'BasePreprocessorExtension' class), but not sure how properly migrate 'MyWixFileVersionExtension' class:

using System;
using System.Diagnostics;
using System.IO;
using WixToolset.Extensibility;

namespace MyWixFileVersionExtension
{
    public class MyWixFileVersionPreprocessorExtension : BasePreprocessorExtension
    {
        private static readonly string[] prefixes = { "fileVersion" };

        public MyWixFileVersionPreprocessorExtension()
        {
            // Set the prefixes for this extension
            this.Prefixes = prefixes;
        }

        public override string EvaluateFunction(string prefix, string function, string[] args)
        {
            if (prefix == "fileVersion")
            {
                // Make sure there actually is a file name
                if (args.Length == 0 || string.IsNullOrEmpty(args[0]))
                    throw new ArgumentException("File name not specified");

                // Make sure the file exists
                if (!File.Exists(args[0]))
                    throw new ArgumentException($"File name {args[0]} does not exist");

                // Get the file version information for the given file
                var fileVersionInfo = FileVersionInfo.GetVersionInfo(args[0]);

                // Get the property that matches the name of the function
                var propertyInfo = fileVersionInfo.GetType().GetProperty(function);

                // Make sure the property exists
                if (propertyInfo == null)
                {
                    throw new ArgumentException($"Unable to find property {function} in FileVersionInfo");
                }

                var result = propertyInfo.GetValue(fileVersionInfo, null)?.ToString();

                if (function.Contains("ProductVersion") && result != null)
                {
                    var indexOfMinus = result.IndexOf('-');
                    if (indexOfMinus > 0)
                    {
                        result = result.Substring(0, indexOfMinus);
                    }
                }

                return result;
            }

            return null;
        }
    }
}

Note: Yes I need extension as this property will be set on build time. As this allows me to show include version in app name (set package name). Custom action would be resolved later, so I could not update package name.

Thanks for any help.

[vdrasutis]

I think I find how to.
The project has to include:

<PackageReference Include="WixToolset.Extensibility" Version="5.0.1" />

and "MyWixFileVersionExtension" should be like this:

using System;
using WixToolset.Extensibility;
using WixToolset.Extensibility.Services;

namespace MyWixFileVersionExtension
{
    public class MyWixFileVersionExtension : IExtensionFactory //WixExtension
    {
        private MyWixFileVersionPreprocessorExtension _versionPreprocessorExtension;

        public MyWixFileVersionExtension(IWixToolsetCoreServiceProvider serviceProvider)
        {
            _serviceProvider = serviceProvider;
        }

        /// <summary>
        /// This exists just to show it is possible to get a service provider to the extension factory.
        /// </summary>
        private IWixToolsetCoreServiceProvider _serviceProvider { get; }

        public bool TryCreateExtension(Type extensionType, out object extension)
        {
            if (extensionType == typeof(IPreprocessorExtension))
            {
                _versionPreprocessorExtension = new MyWixFileVersionPreprocessorExtension();
                extension = _versionPreprocessorExtension;
            }
            else
            {
                extension = null;
            }

            return extension != null;
        }
    }
}