Implemented FtpSource based on FluentFtp library

src/NAppUpdate.Framework/NAppUpdate.Framework.csproj

@@ -69,6 +69,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="System" />
+    <Reference Include="System.Web" />
     <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup>
@@ -97,6 +98,7 @@
       <DesignTime>True</DesignTime>
       <DependentUpon>Resources.resx</DependentUpon>
     </Compile>
+    <Compile Include="Sources\FtpSource.cs" />
     <Compile Include="Sources\IUpdateSource.cs" />
     <Compile Include="Sources\MemorySource.cs" />
     <Compile Include="Sources\SimpleWebSource.cs" />

src/NAppUpdate.Framework/Sources/FtpSource.cs

@@ -0,0 +1,136 @@
+using System;
+using System.IO;
+using System.Net;
+using System.Text;
+using System.Web.UI.WebControls;
+using NAppUpdate.Framework.Common;
+
+namespace NAppUpdate.Framework.Sources
+{
+	public class FtpSource : IUpdateSource
+	{
+		public string HostUrl { get; set; }
+
+		private string feedPath { get; }
+
+		private string feedBasePath => Path.GetDirectoryName(feedPath);
+
+		private int bufferSize = 2048;
+
+		private NetworkCredential credentials { get; }
+
+		/// <param name="hostUrl">Url of ftp server ("ftp://somesite.com/")</param>
+		/// <param name="feedPath">Local ftp path to feed ("/path/to/feed.xml")</param>
+		/// <param name="login">Login of ftp user, if needed</param>
+		/// <param name="password">Password of ftp user, if needed</param>
+		public FtpSource(string hostUrl, string feedPath, string login = null, string password = null)
+		{
+			HostUrl = hostUrl;
+			this.feedPath = feedPath;
+
+			if (login != null && password != null)
+			{
+				credentials = new NetworkCredential(login, password);
+			}
+		}
+
+		private void TryConnectToHost()
+		{
+			var ftpConnRequest = (FtpWebRequest)FtpWebRequest.Create(HostUrl);
+			ftpConnRequest.Method = WebRequestMethods.Ftp.ListDirectory;
+			ftpConnRequest.UsePassive = true;
+			ftpConnRequest.KeepAlive = false;
+			ftpConnRequest.Credentials = credentials;
+
+			try
+			{
+				ftpConnRequest.GetResponse();
+			}
+			catch (WebException e)
+			{
+				throw new WebException($"Failed to connect to host: {HostUrl}. Error message: {e.Message}");
+			}
+		}
+
+		/// <summary>
+		/// Downloads remote file from ftp
+		/// </summary>
+		/// <param name="path">Path to file on server (example: "/path/to/file.txt")</param>
+		/// <param name="localPath">Path on local machine, where file should be saved (if not provided, Temp folder will be used)</param>
+		/// <returns>Path to saved on disk file (Temp folder)</returns>
+		private string DownloadRemoteFile(string path, string localPath = null)
+		{
+			try
+			{
+				string pathToSave = localPath ?? Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString());
+				// Create an FTP Request
+				var ftpRequest =
+					(FtpWebRequest)FtpWebRequest.Create(
+						$@"{HostUrl}{(HostUrl.EndsWith("/") ? string.Empty : "/")}{path}");
+				ftpRequest.Credentials = credentials;
+				// Set options
+				ftpRequest.UseBinary = true;
+				ftpRequest.UsePassive = true;
+				ftpRequest.KeepAlive = true;
+				// Specify the Type of FTP Request 
+				ftpRequest.Method = WebRequestMethods.Ftp.DownloadFile;
+
+				// Establish Return Communication with the FTP Server 
+				using (var ftpResponse = (FtpWebResponse)ftpRequest.GetResponse())
+				{
+					// Get the FTP Server's Response Stream 
+					using (var ftpStream = ftpResponse.GetResponseStream())
+					{
+						// Save data on disk
+						using (var localFileStream = new FileStream(pathToSave, FileMode.Create))
+						{
+							byte[] byteBuffer = new byte[bufferSize];
+							int bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);
+
+							while (bytesRead > 0)
+							{
+								localFileStream.Write(byteBuffer, 0, bytesRead);
+								bytesRead = ftpStream.Read(byteBuffer, 0, bufferSize);
+							}
+						}
+					}
+				}
+
+				return pathToSave;
+			}
+			catch (Exception ex)
+			{
+				throw new WebException(
+					$"An error occurred when trying to download file {Path.GetFileName(path)}: {ex.Message}");
+			}
+		}
+
+		#region IUpdateSource Members
+
+		public String GetUpdatesFeed()
+		{
+			TryConnectToHost();
+
+			string feedFilePath = DownloadRemoteFile(feedPath);
+			string data = File.ReadAllText(feedFilePath);
+
+			// Remove byteorder mark if necessary
+			int indexTagOpening = data.IndexOf('<');
+			if (indexTagOpening > 0)
+			{
+				data = data.Substring(indexTagOpening);
+			}
+
+			return data;
+		}
+
+		public Boolean GetData(String filePath, String basePath, Action<UpdateProgressInfo> onProgress,
+			ref String tempLocation)
+		{
+			DownloadRemoteFile(Path.Combine(feedBasePath, filePath), tempLocation);
+			return true;
+		}
+
+		#endregion
+	}
+}