How to download latest nuget package programmatically in .NET Core?

Question

Need to pull and install the latest version of nugets in .Net Core application

Nuget.Core was the available.however that was in the case of .Net Standard.

Looking to update using Nuget.Client. How to download a nupkg package from nuget programmatically in .NET Core? this is almost same pattern but i couldn't find relevant answers from that question.

.Net standard implementation How to get nuget package version programmatically from a nuget feed?

Also came across https://social.msdn.microsoft.com/Forums/en-US/f10a9c7e-4ad9-4fc5-be94-adfc2eb42a1a/install-a-nuget-package-programmatically?forum=vsx

Need to install latest version this can happen when am running a set of tests and my nuggets needs to updated with latest release.So that my tests will validated against latest nuget versions

Answer 1

So, to add properly a reference into a given .csproj here's what I do:

var CsprojDoc = new XmlDocument();
CsprojDoc.LoadXml("*your_csproj_content*");
var Nsmgr = new XmlNamespaceManager(CsprojDoc.NameTable);
Nsmgr.AddNamespace("x", "http://schemas.microsoft.com/developer/msbuild/2003");

IPackage packageInfos = GetNugetPackage(packageId, packageRepositoryUri);

XmlNode referenceNode = CsprojDoc.CreateNode(XmlNodeType.Element, "Reference", XmlNamespaceValue);
XmlAttribute includeAttribute = CsprojDoc.CreateAttribute("Include");

var targetFwProfile = CsprojDoc.SelectSingleNode("//x:TargetFrameworkProfile", Nsmgr);
string targetFrameworkProfile = string.Empty;
if (!string.IsNullOrEmpty(targetFwProfile?.InnerXml))
{
    targetFrameworkProfile = targetFwProfile.InnerXml;
}

var targetFwAttribute = GetTargetFrameworkFromCsproj();
Regex p = new Regex(@"\d+(\.\d+)+");
Match m = p.Match(targetFwAttribute.FrameworkName);
Version targetFwVersion = Version.Parse(m.Value);

// Get the package's assembly reference matching the target framework from the given '.csproj'.
var assemblyReference =
    packageInfos.AssemblyReferences
        .Where(a => a.TargetFramework.Identifier.Equals(targetFwAttribute.FrameworkName.Split(',').First()))
        .Where(a => a.TargetFramework.Profile.Equals(targetFrameworkProfile))
        .Last(a => (a.TargetFramework.Version.Major.Equals(targetFwVersion.Major) && a.TargetFramework.Version.Minor.Equals(targetFwVersion.Minor)) ||
        a.TargetFramework.Version.Major.Equals(targetFwVersion.Major));

DownloadNugetPackage(packageInfos.Id, packageRepositoryUri, packagesFolderPath, packageInfos.Version.ToFullString());

string dllAbsolutePath = Path.GetFullPath($"{packagesFolderPath}\\{packageInfos.GetFullName().Replace(' ', '.')}\\{assemblyReference.Path}");
var assemblyInfos = Assembly.LoadFile(dllAbsolutePath);

includeAttribute.Value = $"{assemblyInfos.FullName}, processorArchitecture=MSIL";

referenceNode.Attributes.Append(includeAttribute);

XmlNode hintPathNode = CsprojDoc.CreateNode(XmlNodeType.Element, "HintPath", XmlNamespaceValue);
XmlNode privateNode = CsprojDoc.CreateNode(XmlNodeType.Element, "Private", XmlNamespaceValue);

hintPathNode.InnerXml = $"$(SolutionDir)\\packages\\{assemblyReference.Path}";
privateNode.InnerXml = "True";

referenceNode.AppendChild(hintPathNode);
referenceNode.AppendChild(privateNode);
var itemGroupNode = CsprojDoc.SelectSingleNode("//x:Project/x:ItemGroup/x:Reference", Nsmgr).ParentNode;
itemGroupNode.AppendChild(referenceNode);

Here's my DownloadNugetPackage method:

private static void DownloadNugetPackage(string packageId, Uri repoUri, string packagesFolderPath, string version)
{
    IPackageRepository packageRepository = PackageRepositoryFactory.Default.CreateRepository(repoUri.ToString());
    PackageManager packageManager = new PackageManager(packageRepository, packagesFolderPath);

    packageManager.InstallPackage(packageId, SemanticVersion.Parse(version));
}

My GetTargetFrameworkFromCsproj

    public static TargetFrameworkAttribute GetTargetFrameworkFromCsproj()
    {
        XmlNode targetFrameworkNode = CsprojDoc.SelectSingleNode("//x:TargetFrameworkVersion", Nsmgr);
        return new TargetFrameworkAttribute($".NETFramework, Version={targetFrameworkNode.InnerXml}");
    }

And my GetNugetPackage method:

public static IPackage GetNugetPackage(string packageId, Uri repoUri, string version = null)
{
    IPackageRepository packageRepository = PackageRepositoryFactory.Default.CreateRepository(repoUri.ToString());
    IPackage package;

    if (!string.IsNullOrEmpty(version))
    {
        package = packageRepository.FindPackagesById(packageId).SingleOrDefault(p => p.Version.ToFullString().Equals(version));
    }
    else
    {
        package = packageRepository.FindPackagesById(packageId).SingleOrDefault(p => p.IsLatestVersion);
    }

    return package;
}

Note: This time, I'm using the official NuGet package: Nuget.core 2.14 : https://www.nuget.org/packages/NuGet.Core/

Note 2: When I add a new Reference node, in the processorArchitecture attribute, I've hardcoded the value: MSIL

If you want to test it, you might tweak it a bit.

This worked fine for me.