Determine package size using NuGet V3 API

README.md

This is a demonstration of the various ways to get a package size (in bytes) using the NuGet V3 API.

Program.cs

using System;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using NuGet.Common;
using NuGet.Frameworks;
using NuGet.Packaging.Core;
using NuGet.Protocol;
using NuGet.Protocol.Core.Types;
using NuGet.Versioning;

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            MainAsync(args, CancellationToken.None).Wait();
        }

        static async Task MainAsync(string[] args, CancellationToken token)
        {
            // You can log to STDOUT using the following type, which is from NuGet.CommandLine.Xplat.
            // var log = new CommandOutputLogger(LogLevel.Debug);
            var log = NullLogger.Instance;

            // NuGet.org
            var sourceRepository = Repository.Factory.GetCoreV3("https://api.nuget.org/v3/index.json", FeedType.HttpV3);
            var packageIdentity = new PackageIdentity("NuGet.Versioning", NuGetVersion.Parse("4.3.0"));

            // MyGet:
            // var sourceRepository = Repository.Factory.GetCoreV3("https://www.myget.org/F/dotnet/api/v3/index.json", FeedType.HttpV3);
            // var packageIdentity = new PackageIdentity("Microsoft.DotNet.AppDep", NuGetVersion.Parse("1.0.5-prerelease-00001"));

            // This 
            var packageSizeFromCatalog = await GetPackageSizeFromCatalog(packageIdentity, sourceRepository, log, token);
            var packageSizeFromPackageUrl = await GetPackageSizeFromPackageUrl(packageIdentity, sourceRepository, log, token);

            Console.WriteLine($"Package size from catalog: {packageSizeFromCatalog} bytes");
            Console.WriteLine($"Package size from package URL: {packageSizeFromPackageUrl} bytes");
        }

        private static async Task<long?> GetPackageSizeFromCatalog(PackageIdentity packageIdentity, SourceRepository sourceRepository, ILogger log, CancellationToken token)
        {
            var registrationResource = await sourceRepository.GetResourceAsync<RegistrationResourceV3>();
            var packageMetadata = await registrationResource.GetPackageMetadata(packageIdentity, log, token);
            if (packageMetadata == null)
            {
                Console.WriteLine($"The package {packageIdentity} does not exist.");
                return null;
            }

            var catalogItemUrl = packageMetadata.Value<string>("@id");
            Console.WriteLine($"Catalog item URL: {catalogItemUrl}");

            var httpSourceResource = await sourceRepository.GetResourceAsync<HttpSourceResource>();
            var catalogItem = await httpSourceResource.HttpSource.GetJObjectAsync(
                new HttpSourceRequest(catalogItemUrl, log),
                log,
                token);

            return catalogItem.Value<long>("packageSize");
        }

        private static async Task<long?> GetPackageSizeFromPackageUrl(PackageIdentity packageIdentity, SourceRepository sourceRepository, ILogger log, CancellationToken token)
        {
            // Find the package URL.
            var dependencyInfoResource = await sourceRepository.GetResourceAsync<DependencyInfoResource>();
            var package = await dependencyInfoResource.ResolvePackage(
                packageIdentity,
                NuGetFramework.AnyFramework,
                log,
                token);
            if (package == null)
            {
                Console.WriteLine($"The package {packageIdentity} does not exist.");
                return null;
            }

            Console.WriteLine($"Package URL: {package.DownloadUri.AbsoluteUri}");
            
            long? packageSize = null;
            using (var httpClient = new HttpClient())
            {
                // Make a HEAD request to the package URL.
                // We can't use NuGet's HttpSource here due to https://github.com/NuGet/Home/issues/6112.
                using (var headRequest = new HttpRequestMessage(HttpMethod.Head, package.DownloadUri))
                using (var headResponse = await httpClient.SendAsync(headRequest))
                {
                    if (headResponse.IsSuccessStatusCode &&
                        headResponse.Content.Headers.ContentLength.HasValue)
                    {
                        Console.WriteLine("Got Content-Length header.");
                        packageSize = headResponse.Content.Headers.ContentLength;
                    }
                }

                // If that didn't work, download the package to get the size.
                if (!packageSize.HasValue)
                {
                    Console.WriteLine("Downloading package to determine file size.");
                    using (var getRequest = new HttpRequestMessage(HttpMethod.Get, package.DownloadUri))
                    using (var getResponse = await httpClient.SendAsync(getRequest, HttpCompletionOption.ResponseHeadersRead))
                    using (var getStream = await getResponse.Content.ReadAsStreamAsync())
                    {
                        getResponse.EnsureSuccessStatusCode();

                        var buffer = new byte[16 * 1024];
                        int read;
                        long totalBytes = 0;
                        while ((read = await getStream.ReadAsync(buffer, 0, buffer.Length)) > 0)
                        {
                            totalBytes += read;
                        }

                        packageSize = totalBytes;
                    }
                }
            }
            
            return packageSize;
        }
    }
}