Find package updates available for a packages.config file

updates.cs

// install-package nuget.protocol.visualstudio

using NuGet.Configuration;
using NuGet.Packaging;
using NuGet.Protocol.Core.Types;
using NuGet.Protocol.VisualStudio;
using System;
using System.IO;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;

namespace ConsoleApplication32
{
    class Program
    {
        static void Main(string[] args)
        {
            Run().Wait();
        }

        static async Task Run()
        {
            // Target
            var packagesConfigPath = @"D:\tmp\test\ConsoleApplication1\ConsoleApplication1\packages.config";

            var includePrelease = true;
            var includeUnlisted = false;

            var packagesConfig = new PackagesConfigReader(File.OpenRead(packagesConfigPath));

            // Read all nuget.config files
            var nugetConfigSettings = Settings.LoadDefaultSettings(
                Path.GetDirectoryName(packagesConfigPath), 
                configFileName: null,
                machineWideSettings: null);

            // Create source repositories
            SourceRepositoryProvider sourceProvider = new SourceRepositoryProvider(
                nugetConfigSettings,
                Repository.Provider.GetVisualStudio());

            var sources = sourceProvider.GetRepositories().ToList();

            var token = CancellationToken.None;

            foreach (var installedPackage in packagesConfig.GetPackages())
            {
                Console.WriteLine($"Installed package: {installedPackage.PackageIdentity}");

                // Check for updates in each source
                foreach (var source in sources)
                {
                    var resource = await source.GetResourceAsync<MetadataResource>(token);

                    var latestVersion = await resource.GetLatestVersion(
                        packageId: installedPackage.PackageIdentity.Id,
                        includePrerelease: includePrelease,
                        includeUnlisted: includeUnlisted,
                        token: token);

                    if (installedPackage.PackageIdentity.Version < latestVersion)
                    {
                        Console.WriteLine($"Update available! Version: {latestVersion} Source: {source.PackageSource}");
                    }
                    else
                    {
                        Console.WriteLine($"No updates available from: {source.PackageSource}");
                    }
                }
            }
        }
    }
}