如何在.NET Core中以编程方式从nuget下载nupkg包？

Question

在.NET Framework中，我使用此示例以编程方式使用nuget

Play with Packages, programmatically!

是否有任何等效的.NET Core源？

//ID of the package to be looked up
string packageID = "EntityFramework";

//Connect to the official package repository
IPackageRepository repo = PackageRepositoryFactory.Default.CreateRepository("https://packages.nuget.org/api/v2");

//Get the list of all NuGet packages with ID 'EntityFramework'       
List<IPackage> packages = repo.FindPackagesById(packageID).ToList();

//Filter the list of packages that are not Release (Stable) versions
packages = packages.Where (item => (item.IsReleaseVersion() == false)).ToList();

//Iterate through the list and print the full name of the pre-release packages to console
foreach (IPackage p in packages)
{
    Console.WriteLine(p.GetFullName());
}

//---------------------------------------------------------------------------

//ID of the package to be looked up
string packageID = "EntityFramework";

//Connect to the official package repository
IPackageRepository repo = PackageRepositoryFactory.Default.CreateRepository("https://packages.nuget.org/api/v2");

//Initialize the package manager
string path = <PATH_TO_WHERE_THE_PACKAGES_SHOULD_BE_INSTALLED>
PackageManager packageManager = new PackageManager(repo, path);

//Download and unzip the package
packageManager.InstallPackage(packageID, SemanticVersion.Parse("5.0.0"));

我想以编程方式下载并安装任何软件包。

https://api.nuget.org/v3/index.json

Answer 1

您展示的代码示例使用的是.NET Core上不支持的NuGet 2。您需要使用NuGet 3或（即将发布的）NuGet 4.这些API与NuGet 2有很大的突破。其中一个重大变化是NuGet.Core在获胜时已经过时＆＃39;移植到.NET Core。

在docs.microsoft.com上查看NuGet API v3以获取有关NuGet 3的信息。在撰写本文时，此文档基本上是一个很大的TODO，并且没有太多信息。

以下是一些更有用的博文。

Exploring the NuGet v3 Libraries, Part 1 Introduction and concepts

Exploring the NuGet v3 Libraries, Part 2

Exploring the NuGet v3 Libraries, Part 3

当然，您可以随时通过NuGet的源代码了解更多示例。大多数核心逻辑都存在于https://github.com/nuget/nuget.client。

Answer 2

实现此目标的最佳方法是在项目中引用 NugetDownloader 软件包，并以编程方式使用它下载其他任何软件包

Install-Package NugetDownloader

源代码及其帮助指南可从以下网站获得： https://github.com/paraspatidar/NugetDownloader

以下是有关实现方法的快速示例：

string packageName="Newtonsoft.json";
string version="10.2.1.0"; \\optional

\\initilize NugetEngine from NugetDownloader namespaces

NugetEngine nugetEngine = new NugetEngine();
nugetEngine.GetPackage(packageName, version).Wait();

示例客户端也可以在https://github.com/paraspatidar/NugetDownloader/tree/master/NugetDownloaderTestConsole

获得

或者，如果您想从头开始构建Nugetdownloader引擎，那么您可能还会引用https://github.com/Azure/azure-functions-host/blob/dev/src/WebJobs.Script/Description/DotNet/PackageManager.cs，因为它具有类似的实现，但是对代码的理解和提取过多。

Answer 3

我也一直在寻找这样做的时间，并找到了有关如何做到这一点的 Microsoft 指南。一旦您知道流程的切入点，其他一切都应该是直截了当的。

这适用于 .NET Core（在 3.1 上测试）并使用 Nuget v3。

指南：https://docs.microsoft.com/en-us/nuget/reference/nuget-client-sdk

列出包的示例：

ILogger logger = NullLogger.Instance;
CancellationToken cancellationToken = CancellationToken.None;

SourceCacheContext cache = new SourceCacheContext();
SourceRepository repository = Repository.Factory.GetCoreV3("https://api.nuget.org/v3/index.json");
FindPackageByIdResource resource = await repository.GetResourceAsync<FindPackageByIdResource>();

IEnumerable<NuGetVersion> versions = await resource.GetAllVersionsAsync(
    "Newtonsoft.Json",
    cache,
    logger,
    cancellationToken);

foreach (NuGetVersion version in versions)
{
    Console.WriteLine($"Found version {version}");
}

下载包的示例：

ILogger logger = NullLogger.Instance;
CancellationToken cancellationToken = CancellationToken.None;

SourceCacheContext cache = new SourceCacheContext();
SourceRepository repository = Repository.Factory.GetCoreV3("https://api.nuget.org/v3/index.json");
FindPackageByIdResource resource = await repository.GetResourceAsync<FindPackageByIdResource>();

string packageId = "Newtonsoft.Json";
NuGetVersion packageVersion = new NuGetVersion("12.0.1");
using MemoryStream packageStream = new MemoryStream();

await resource.CopyNupkgToStreamAsync(
    packageId,
    packageVersion,
    packageStream,
    cache,
    logger,
    cancellationToken);

Console.WriteLine($"Downloaded package {packageId} {packageVersion}");

using PackageArchiveReader packageReader = new PackageArchiveReader(packageStream);
NuspecReader nuspecReader = await packageReader.GetNuspecReaderAsync(cancellationToken);