Class SftpTransferOptions

Options for SftpClient's uploads and downloads.

public sealed class SftpTransferOptions

Inherited Members: object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.ReferenceEquals(object, object)

object.ToString()

Properties

MaxRequestsInFlight: How many reads or writes may be in flight at once (default 64, as OpenSSH's sftp). More helps on links with latency.

Overwrite: Replace an existing destination file (default true, as sftp put and get do); otherwise it is an error.

Preserve: Copy the source's modification and access times, and its permission bits (read, write and execute for the owner, the group and others), to the destination, as sftp -p does. Permissions are copied only where the receiving side has Unix modes: a download to Windows keeps the times only, and an upload from Windows sends none. Unlike OpenSSH, setuid, setgid and the sticky bit are never copied, so a server cannot hand this machine a setuid file.

Progress: Reports each file's progress: its path, the bytes transferred so far and its size, when known.

Resume: Continue an interrupted transfer, as sftp's reget and reput do: the destination's existing bytes are taken as the source's first ones, and only the rest is sent; a destination larger than the source is an error. Nothing checks that the existing bytes match, so use it for the same file only. A failed download with this set keeps what arrived. Overrides Overwrite for an existing destination.

Segments: How many parts of one file DownloadFileAsync(string, string, SftpTransferOptions?, CancellationToken) fetches at once, each over its own SFTP session on the same connection (default 1: one session). Each session is an SSH channel with its own flow-control window, and on OpenSSH its own sftp-server process, so on a link with high latency several segments move more than one session can: one session carries at most its 2 MiB window per round trip. It does not help where the bandwidth, or the server's single connection, is the limit. Files smaller than 1 MiB per segment use fewer segments; the server may allow fewer sessions (sshd's MaxSessions, 10 by default), and then fewer are used. Ignored with Resume (only a sequential download leaves a prefix to resume from) and by DownloadAsync(string, Stream, SftpTransferOptions?, CancellationToken), which writes a stream in order. Each extra session opens the file by path, so a file whose size or modification time has changed by then (replaced, or still being written) fails the download.