Changes

General

• Increase initial window size for SSH channels from 2 MB to 2147483647 (2^31 - 1) bytes. This results in less protocol overhead when receiving data from a SSH server.

SftpClient

• When the read buffer is empty, SftpFileStream.Read(byte[], int, int) only writes those bytes to the buffer that go beyond the number of bytes requested by the caller.
• Reduced memory allocations in SftpFileStream by lazily allocating read and write buffer.
• Improved compatibility of SftpFileStream.SetLength(long value) with System.IO.FileStream (PR #272):
  • Flush buffers before changing the length of stream.
  • Move the current position to the last byte of the stream if the current position is greater than the new length.
• Eliminated extra read from server in SftpFileStream to determine EOF.
• Greatly improved performance of SftpClient.(Begin)DownloadFile(...) by asynchronously reading ahead chunks (issue #145 and #100).

Breaking changes

SftpClient

• The IsAsync property was removed from SftpFileStream. Previously this property always returned false.

• The read and write position in SftpFileStream are no longer tracked separately. Reading from or seeking in the SftpFileStream will now also affect the position at which a subsequent write is performed, and vice versa (issue #253).

  For example, the following code snippet will now write "123456" to the console:

    var buffer = Encoding.UTF8.GetBytes("123456");

    using (var client = new SftpClient("host", "user", "pwd"))
    {
        client.Connect();

        using (var ws = client.OpenWrite(path))
        {
            ws.Write(buffer, 0, 3);
        }

        using (var ws = client.OpenWrite(path))
        {
            ws.Seek(3, SeekOrigin.Begin);
            ws.Write(buffer, 3, 3);
        }

        Console.WriteLine(client.ReadAllText(path, Encoding.UTF8));
    }

• To improve compatibility of SftpFileStream with System.IO.FileStream, Append mode is now only allowed when combined with write-only access (issue #267). This only affects SftpClient.Open(string path, FileMode mode, FileAccess access).

  The following code snippet will now throw an ArgumentException:

    using (var client = new SftpClient("host", "user", "pwd"))
    {
        client.Connect();
  
        using (var fs = client.Open("/home/user/file.log", FileMode.Append, FileShare.Read))
        {
        }
    }
  

  Result: System.ArgumentException: Append mode can be requested only when combined with write-only access.

• To improve compatibility of SftpClient with System.IO.File, the following methods now use UTF-8 encoding without a Byte-Order Mark (BOM):

  • void AppendAllLines(string path, IEnumerable<string> contents)
  • void AppendAllText(string path, string contents)
  • StreamWriter AppendText(string path)
  • StreamWriter CreateText(string path)
  • void WriteAllLines(string path, IEnumerable<string> contents)
  • void WriteAllLines(string path, string[] contents)
  • void WriteAllText(string path, string contents)

Fixes

General

• ConnectSocks5() throws a ProxyException with a wrong message (issue #167).
• Comments in ProxyException.cs are not relevant (issue #163).
• SSH exception after client connect using .NET 3.5 version (issue #113).

SftpClient

• SftpFileStream allows invalid combinations of FileMode and FileAccess (issue #191).
• SftpFileStream.ReadByte() throws ArgumentException when no data is available in read buffer (issue #173).
• SftpFileStream also sends SSH_FXP_FSTAT upon initialization when mode is not Append (issue #154).
• In Append mode, SftpFileStream throws a SftpPathNotFoundException when the specified file does not exist (issue #266).