GiantsTools/Giants.Launcher/Updater/Updater.cs

using System;
using System.ComponentModel;
using System.IO;
using System.Net;
using System.Threading.Tasks;
using System.Windows.Forms;
using Giants.WebApi.Clients;

namespace Giants.Launcher
{
    public class Updater
    {
		private readonly Version appVersion;
        private readonly AsyncCompletedEventHandler updateCompletedCallback;
		private readonly DownloadProgressChangedEventHandler updateProgressCallback;
		
		public Updater(
			Version appVersion,
			AsyncCompletedEventHandler updateCompletedCallback,
			DownloadProgressChangedEventHandler updateProgressCallback)
		{
			this.appVersion = appVersion;
            this.updateCompletedCallback = updateCompletedCallback;
            this.updateProgressCallback = updateProgressCallback;
        }

		public Task UpdateApplication(ApplicationType applicationType, VersionInfo versionInfo)
        {
			try
			{
				if (this.ToVersion(versionInfo.Version) > this.appVersion)
				{
					this.StartApplicationUpdate(applicationType, versionInfo);
				}
			}
			catch (Exception)
            {
            }

			return Task.CompletedTask;
        }

		private int GetHttpFileSize(Uri uri)
		{
			HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(uri);
			req.Proxy = null;
			req.Method = "HEAD";
			HttpWebResponse resp = (HttpWebResponse)req.GetResponse();

			if (resp.StatusCode == HttpStatusCode.OK && int.TryParse(resp.Headers.Get("Content-Length"), out int contentLength))
			{
				resp.Close();
				return contentLength;
			}

			resp.Close();
			return -1;

		}

		private void StartApplicationUpdate(ApplicationType applicationType, VersionInfo versionInfo)
		{
			// Display update prompt
			string updateMsg = applicationType == ApplicationType.Game ?
								string.Format(Resources.UpdateAvailableText, this.ToVersion(versionInfo.Version).ToString()) :
								string.Format(Resources.LauncherUpdateAvailableText, this.ToVersion(versionInfo.Version).ToString());

			if (MessageBox.Show(updateMsg, Resources.UpdateAvailableTitle, MessageBoxButtons.YesNo) == DialogResult.No)
			{
				return; // User declined update
			}

			string patchFileName = Path.GetFileName(versionInfo.InstallerUri.AbsoluteUri);
			string localPath = Path.Combine(Path.GetTempPath(), patchFileName);

			// Delete the file locally if it already exists, just to be safe
			if (File.Exists(localPath))
			{
				File.Delete(localPath);
			}

			int fileSize = this.GetHttpFileSize(versionInfo.InstallerUri);
			if (fileSize == -1)
			{
				string errorMsg = string.Format(Resources.UpdateDownloadFailedText, "File not found on server.");
				MessageBox.Show(errorMsg, Resources.UpdateDownloadFailedTitle, MessageBoxButtons.OK, MessageBoxIcon.Error);
				return;
			}

			var updateInfo = new UpdateInfo()
            {
				FilePath = localPath,
				FileSize = fileSize,
				ApplicationType = applicationType
            };

			// Download the update
			// TODO: Super old code, replace this with async HttpClient
			WebClient client = new WebClient(); 
            client.DownloadFileAsync(versionInfo.InstallerUri, localPath, updateInfo);
			client.DownloadFileCompleted += this.updateCompletedCallback;
			client.DownloadProgressChanged += this.updateProgressCallback;
		}

        private Version ToVersion(AppVersion version)
		{
			return new Version(version.Major, version.Minor, version.Build, version.Revision);
		}
	}
}