More .NET libraries
-
Rebex SFTP
.NET SFTP client
-
Rebex File Transfer Pack
FTP/SSL and SFTP together
-
Rebex Total Pack
All Rebex .NET libraries together
Back to feature list...
Single file operations
On this page:
Single-file upload and download
Use PutFile
method to upload a single file, and GetFile
method to download it.
Both methods require a target name, which means it's possible to use a different target file name if needed.
// upload a local file to server ftp.PutFile(@"C:\MyData\file.txt", "/MyData/file.txt"); // download from server to a local file using a different name ftp.GetFile("/MyData/file.txt", @"C:\MyData\copy-file.txt");
' upload a local file to server ftp.PutFile("C:\MyData\file.txt", "/MyData/file.txt") ' download from server to a local file using a different name ftp.GetFile("/MyData/file.txt", "C:\MyData\copy-file.txt")
These methods overwrite any existing files. To check whether a remote file exists,
use FileExists
method.
Upload
and Download
methods. They accept single-file input as well and support both single-file and multi-file transfers.
Stream-based upload and download
Both PutFile
and GetFile
methods accept a System.IO.Stream
object, making it possible to
transfer data from/to any kind of stream.
For example, use MemoryStream
when processing data in memory, without having to create temporary disk files:
Upload from memory:
// prepare data byte[] data = System.Text.Encoding.UTF8.GetBytes("test data"); // convert data to a memory stream var stream = new MemoryStream(data); // upload data from memory ftp.PutFile(stream, "/MyData/file.txt");
' prepare data Dim data() As Byte = System.Text.Encoding.UTF8.GetBytes("test data") ' convert data to a memory stream Dim stream As New MemoryStream(data) ' upload data from memory ftp.PutFile(stream, "/MyData/file.txt")
Download to memory:
// download a remote file into a memory stream var stream = new MemoryStream(); ftp.GetFile("/MyData/file.txt", stream); // convert memory stream to data byte[] data = stream.ToArray();
' download a remote file into a memory stream Dim stream As New MemoryStream() ftp.GetFile("/MyData/file.txt", stream) ' convert memory stream to data Dim data() As Byte = stream.ToArray()
Deleting a file
To delete a remote file, use DeleteFile
method.
For example, to delete a remote file that doesn't exist locally, use the following code:
// if local file is deleted if (!File.Exists(@"C:\MyData\file.txt")) { // delete remote file as well ftp.DeleteFile("/MyData/file.txt"); }
' if local file is deleted If Not File.Exists("C:\MyData\file.txt") Then ' delete remote file as well ftp.DeleteFile("/MyData/file.txt") End If
Tip: For deleting multiple files or non-empty directories,
use Delete
method.
Rename/move a file
To rename a remote file or directory, use Rename
method.
It can also be used for moving a remote file or directory to another location on the file system of the remote host.
// rename a remote file ftp.Rename("/MyData/a.txt", "/MyData/b.txt"); // move a remote file ftp.Rename("/MyData/file.txt", "/Backups/file.txt");
' rename a remote file ftp.Rename("/MyData/a.txt", "/MyData/b.txt") ' move a remote file ftp.Rename("/MyData/file.txt", "/Backups/file.txt")
Tip: For moving files between client and server,
use Upload
or Download
methods with the TransferMethod.Move
argument specified.
Checking file existence
To check whether a remote file already exists, use FileExists
method.
This is useful, for example, when you are about to upload a file, but would like to ask the user whether to overwrite an existing target file first:
// check whether a remote file exists bool exists = ftp.FileExists("/MyData/file.txt"); if (exists) { // prompt the user // ... }
' check whether a remote file exists Dim exists = ftp.FileExists("/MyData/file.txt") If exists Then ' prompt the user ' ... End If
Please be aware that this operation is not a part of the original FTP protocol. Although FileExists
tries several ways to check whether the file exists
and works well with almost all FTP servers, it may fail on some legacy FTP servers with a "not supported" exception.
Getting file length
To retrieve the length of a remote file, use GetFileLength
method:.
This can be used to determine the current remote file length when resuming a broken transfer or in order to ask the user for permission before downloading a large file over a slow network:
// get the length of a remote file long length = ftp.GetFileLength("/MyData/file.txt"); // large downloads need user permission if (length > 1024 * 1024) { // prompt the user what to do with file > 1 MB // ... }
' get the length of a remote file Dim length = ftp.GetFileLength("/MyData/file.txt") ' large downloads need user permission If length > 1024 * 1024 Then ' prompt the user what to do with file > 1 MB ' ... End If
Getting and setting file date/time
To retrieve the last modification date/time of a remote file, use GetFileDateTime
method. To set it, use SetFileDateTime
method.
Getting remote time
string localPath = @"C:\MyData\file.txt"; string remotePath = "/MyData/file.txt"; DateTime remoteTime = ftp.GetFileDateTime(remotePath); // download file and set local time appropriately ftp.GetFile(remotePath, localPath); File.SetLastWriteTime(localPath, remoteTime);
Dim localPath = "C:\MyData\file.txt" Dim remotePath = "/MyData/file.txt" Dim remoteTime = ftp.GetFileDateTime(remotePath) ' download file and set local time appropriately ftp.GetFile(remotePath, localPath) File.SetLastWriteTime(localPath, remoteTime)
Setting remote time
string localPath = @"C:\MyData\file.txt"; string remotePath = "/MyData/file.txt"; DateTime localTime = new FileInfo(localPath).LastWriteTime; // upload file and set remote time appropriately ftp.PutFile(localPath, remotePath); ftp.SetFileDateTime(remotePath, localTime);
Dim localPath = "C:\MyData\file.txt" Dim remotePath = "/MyData/file.txt" Dim localTime = New FileInfo(localPath).LastWriteTime ' upload file and set remote time appropriately ftp.PutFile(localPath, remotePath) ftp.SetFileDateTime(remotePath, localTime)
Depending on the remote FTP server software, the returned time would be in local or universal time zone. See an article about treating time zones in FTP GetFileDateTime method.
Getting file checksums
To make it possible to verify the file has been transferred correctly, some FTP servers support checksum calculation, making it possible to compare checksums of local and remote files.
string localPath = @"C:\MyData\file.txt"; string remotePath = "/MyData/file.txt"; // upload the file ftp.PutFile(localPath, remotePath); // get checksum algorithms supported by the server ChecksumAlgorithm[] checksumAlgorithms = ftp.GetSupportedChecksumAlgorithms(); if (checksumAlgorithms.Length > 0) { // compute checksums // choose the first checksum type ChecksumAlgorithm checksumAlgorithm = checksumAlgorithms[0]; // retrieve checksum from the server string remoteChecksum = ftp.GetChecksum(remotePath, checksumAlgorithm); // calculate local checksum string localChecksum = LocalItem.GetChecksum(localPath, checksumAlgorithm); // compare checksums if (remoteChecksum == localChecksum) Console.WriteLine("File uploaded and verified."); else Console.WriteLine("File uploaded with errors."); } else { Console.WriteLine("Server does not support checksums."); }
Dim localPath = "C:\MyData\file.txt" Dim remotePath = "/MyData/file.txt" ' upload the file ftp.PutFile(localPath, remotePath) ' get checksum types supported by the server Dim checksumAlgorithms() As ChecksumAlgorithm = ftp.GetSupportedChecksumAlgorithms() If checksumAlgorithms.Length > 0 Then ' compute checksums ' choose the first checksum type Dim checksumAlgorithm = checksumAlgorithms(0) ' retrieve checksum from the server Dim remoteChecksum As String = ftp.GetChecksum(remotePath, checksumAlgorithm) ' calculate local checksum Dim localChecksum As String = LocalItem.GetChecksum(localPath, checksumAlgorithm) ' compare checksums If remoteChecksum = localChecksum Then Console.WriteLine("File uploaded and verified.") Else Console.WriteLine("File uploaded with errors.") End If Else Console.WriteLine("Server does not support checksums.") End If
Partial file transfer (appending)
GetFile
and PutFile
methods make it possible to download or upload a part of a file.
This is used for appending data to an existing file or to resume broken transfers.
To upload a file part, use three additional parameters: local offset, remote offset and number of bytes you want to transfer. To download a file part, only two parameters are available: local offset and remote offset. Local offset is not required for stream-based methods - data is read/written from/to the current stream position.
string localPath = @"C:\MyData\part7.txt"; string remotePath = "/MyData/summary.txt"; string header = string.Format("<FILE>: {0}\n", localPath); long localFileLength = new FileInfo(localPath).Length; long remoteFileLength = ftp.GetFileLength(remotePath); // append header for part7.txt to summary.txt from memory MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(header)); ftp.PutFile(ms, remotePath, remoteFileLength, // remote offset ms.Length); // number of bytes to upload // update remote length remoteFileLength += ms.Length; // append data from part7.txt to summary.txt ftp.PutFile(localPath, remotePath, 0, // local offset remoteFileLength, // remote offset localFileLength); // number of bytes to upload
Dim localPath = "C:\MyData\part7.txt" Dim remotePath = "/MyData/summary.txt" Dim header = String.Format("<FILE>: {0}" & vbLf, localPath) Dim localFileLength = New FileInfo(localPath).Length Dim remoteFileLength = ftp.GetFileLength(remotePath) ' append header for part7.txt to summary.txt from memory Dim ms = New MemoryStream(Encoding.UTF8.GetBytes(header)) ftp.PutFile(ms, remotePath, remoteFileLength, ms.Length) ' remote offset, number of bytes to upload ' update remote length remoteFileLength += ms.Length ' append data from part7.txt to summary.txt ftp.PutFile(localPath, remotePath, 0, remoteFileLength, localFileLength) ' local offset, remote offset, number of bytes to upload
AppendFile
method to append data to a file at the server, it uses FTP 'APPE
' command that is only supported
by some servers. Using PutFile
method might be a better choice.
Partial file transfer (resuming)
But if you prefer to have more control over the process, partial file transfer support
in GetFile
and PutFile
methods might be useful.
To resume a file transfer, determine the length of the local file and
the length of the remote file.
Then transfer the missing part.
Resuming upload:
string localPath = @"C:\MyData\file.txt"; string remotePath = "/MyData/file.txt"; long localFileLength = new FileInfo(localPath).Length; long remoteFileLength = ftp.GetFileLength(remotePath); long remains; // resume failed upload remains = localFileLength - remoteFileLength; if (remains > 0) { ftp.PutFile(localPath, remotePath, remoteFileLength, // local offset remoteFileLength, // remote offset remains); // number of bytes to upload }
Dim localPath = "C:\MyData\file.txt" Dim remotePath = "/MyData/file.txt" Dim localFileLength = New FileInfo(localPath).Length Dim remoteFileLength = ftp.GetFileLength(remotePath) Dim remains As Long ' resume failed upload remains = localFileLength - remoteFileLength If remains > 0 Then ftp.PutFile(localPath, remotePath, remoteFileLength, remoteFileLength, remains) ' local offset, remote offset, number of bytes to upload End If
Resuming download:
string localPath = @"C:\MyData\file.txt"; string remotePath = "/MyData/file.txt"; long localFileLength = new FileInfo(localPath).Length; long remoteFileLength = ftp.GetFileLength(remotePath); // resume failed download if (remoteFileLength > localFileLength) { ftp.GetFile(remotePath, localPath, localFileLength, // remote offset localFileLength); // local offset }
Dim localPath = "C:\MyData\file.txt" Dim remotePath = "/MyData/file.txt" Dim localFileLength = New FileInfo(localPath).Length Dim remoteFileLength = ftp.GetFileLength(remotePath) ' resume failed download If remoteFileLength > localFileLength Then ftp.GetFile(remotePath, localPath, localFileLength, localFileLength) ' remote offset, local offset End If
Back to feature list...