Download NuGet Catalog Using C# Console App

cSharpNuGetDownloader.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using Newtonsoft.Json.Linq;

namespace NuGetDownloader
{
    class Program
    {
        public static List<jsonSource> jsonSources = new List<jsonSource>();
        public static Dictionary<string, Version> packageDictionary = new Dictionary<string, Version>();
        static void Main(string[] args)
        {
            using (WebClient client = new WebClient())
            {
                // Create a list of source sites
                List<JToken> response = JObject
                    .Parse(client.DownloadString("https://api.nuget.org/v3/catalog0/index.json")
                    .Replace("@", ""))
                    .Children().ToList()[8].Children().Children().ToList();

                // Add each JSON object from the 'response' to the list of JSON sources
                response.ForEach(item => jsonSources.Add(item.ToObject<jsonSource>()));

                // Parse the 5000 lists of 500 items each (15 at a time) and build dictionary of highest version packages
                Parallel.ForEach(jsonSources, new ParallelOptions { MaxDegreeOfParallelism = 15 }, buildDictionary);

                // Download Highest Versions from the packageDictionary
                Parallel.ForEach(packageDictionary, new ParallelOptions { MaxDegreeOfParallelism = 15 }, downloadDictionaryItems);

                Console.WriteLine("Completed download at: " + System.DateTime.Now);
                Console.ReadLine();
            }
        }

        private static void buildDictionary(jsonSource obj)
        {
            // Get the page number (page1525.json) is 1525
            int myPage = Int32.Parse(Regex.Match(obj.id.Split('/').Last(), @"\d+").Value);

            List<JToken> packageResponse = new List<JToken>();

            // Condition below is due to format change at page 1525
            if (myPage < 1525)
            {
                WebClient client = new WebClient();

                packageResponse = JObject.Parse(client.DownloadString(obj.id)
                        .Replace("@", "").Replace("nuget:", "nuget"))
                    .Children().ToList()[5].Children().Children().ToList();
            }
            else
            {
                WebClient client = new WebClient();
                packageResponse = JObject.Parse(client.DownloadString(obj.id))
                    .Children().ToList()[6].Children().Children().ToList();
            }
            packageResponse.ForEach(item =>
            {
                try
                {
                    packageSource myItem = item.ToObject<packageSource>();
                    if (packageDictionary.ContainsKey(myItem.nugetId))
                    {
                        Version vNew = myItem.nugetVersion;
                        Version vExists = packageDictionary[myItem.nugetId];

                        packageDictionary[myItem.nugetId] =
                            (vNew.CompareTo(vExists) > 0) ? vNew : vExists;
                    }
                    else
                    {
                        packageDictionary.Add(item.ToObject<packageSource>().nugetId,
                            item.ToObject<packageSource>().nugetVersion);
                    }
                }
                catch (Exception ex) { }
            });
            Console.WriteLine(packageDictionary.Count + " - " + obj.id);
        }

        private static void downloadDictionaryItems(KeyValuePair<string, Version> entry)
        {
            try
            {
                WebClient client = new WebClient();
                string downloadFile = "https://www.nuget.org/api/v2/package/" + entry.Key + "/" + entry.Value;
                string outFile = "C:" + "\\" + "Nuget" + "\\" + entry.Key + "." + entry.Value + "." + "nupkg";
                client.DownloadFile(downloadFile, outFile);
            }
            catch(Exception ex) { //Swallow it }
        }

        public class jsonSource
        {
            public string id { get; set; }
        }
        public class packageSource
        {
            public string nugetId { get; set; }
            public Version nugetVersion { get; set; }
        }
    }
}