Ftp Client

FtpClient provides basic operations for communicating with the MAVLink FTP server. Use the FTP client if you need to exchange files over a MAVLink network, for example, to download logs from the drone (server).

Use case

As an example we will show you how to create a directory and list its contents.

Get FtpClient through the microservice locator:

var ftpClient = drone.GetMicroservice<IFtpClient>() 
    ?? throw new Exception("Ftp client not found");

Call CreateDirectory to create a new folder in the root directory:

var result = await ftpClient.CreateDirectory("/FolderExample", cancel);

Call ListDirectory to get data about the root directory:

// create buffer to store directory's data
var buffer = new char[MavlinkFtpHelper.FtpEncoding.GetMaxCharCount(MavlinkFtpHelper.MaxDataSize)];
var offset = 0u; // use offsets to scan directories with a lot of entities.
var directory = "/"; // use '/' to scan the root folder
var size = await ftpClient.ListDirectory(directory, offset, buffer, cancel);

Print the directory listing (decoded characters) to the console:

Console.WriteLine("Directory: " + string.Join(string.Empty, buffer));

Api

MavlinkFtpClientConfig

Property	Type	Default	Description
`TimeoutMs`	`int`	`500`	Timeout (in milliseconds) for a single FTP command.
`CommandAttemptCount`	`int`	`6`	How many times to retry a command on timeout failure.
`TargetNetworkId`	`byte`	`0`	Target MAVLink network ID (target_network) used for routing.
`BurstTimeoutMs`	`int`	`1000`	Burst-read inactivity timeout (in milliseconds).

IFtpClient

MAVLink FTP (File Transfer Protocol) client abstraction. Provides remote filesystem operations over the MAVLink FTP microservice.

Method	Return Type	Description
`OpenFileRead(string path, CancellationToken cancel = default)`	`Task<ReadHandle>`	Opens a file for reading on the remote filesystem.
`OpenFileWrite(string path, CancellationToken cancel = default)`	`Task<WriteHandle>`	Opens a file for writing on the remote filesystem.
`CreateDirectory(string path, CancellationToken cancellationToken = default)`	`Task<FileTransferProtocolPacket>`	Creates a directory on the remote filesystem.
`CreateFile(string path, CancellationToken cancellationToken = default)`	`Task<FileTransferProtocolPacket>`	Creates an empty file on the remote filesystem.
`ResetSessions(CancellationToken cancellationToken = default)`	`Task<FileTransferProtocolPacket>`	Resets (closes) all FTP sessions on the remote side.
`RemoveDirectory(string path, CancellationToken cancellationToken = default)`	`Task<FileTransferProtocolPacket>`	Removes a directory at the specified path on the remote filesystem.
`RemoveFile(string path, CancellationToken cancellationToken = default)`	`Task<FileTransferProtocolPacket>`	Removes a file at the specified path on the remote filesystem.
`CalcFileCrc32(string path, CancellationToken cancellationToken = default)`	`Task<uint>`	Calculates CRC32 of a remote file.
`TruncateFile(TruncateRequest request, CancellationToken cancellationToken = default)`	`Task<FileTransferProtocolPacket>`	Truncates a remote file to the specified byte offset.
`WriteFile(WriteRequest request, Memory<byte> buffer, CancellationToken cancellationToken = default)`	`Task<FileTransferProtocolPacket>`	Writes a chunk of bytes into an already opened write session on the remote filesystem.
`BurstReadFile(ReadRequest request, Action<FileTransferProtocolPacket> onBurstData, CancellationToken cancel = default)`	`Task`	Performs burst file read from the remote filesystem. Data is delivered to onBurstData as packets arrive.
`Rename(string path1, string path2, CancellationToken cancel = default)`	`Task<FileTransferProtocolPacket>`	Renames or moves a file/directory on the remote filesystem.
`TerminateSession(byte session, CancellationToken cancel = default)`	`Task`	Terminates an FTP session on the remote side.
`ReadFile(ReadRequest request, CancellationToken cancel = default)`	`Task<FileTransferProtocolPacket>`	Reads a chunk of bytes from an already opened read session on the remote filesystem.
`ReadFile(ReadRequest request, Memory<byte> buffer, CancellationToken cancel = default)`	`Task<ReadResult>`	Reads file data into a byte memory buffer from the remote filesystem.
`ReadFile(ReadRequest request, IBufferWriter<byte> buffer, CancellationToken cancel = default)`	`Task<ReadResult>`	Reads file data into a buffer from the remote filesystem.
`ListDirectory(string path, uint offset, CancellationToken cancel = default)`	`Task<FileTransferProtocolPacket>`	Lists a directory starting at the given offset cursor from the remote filesystem.
`ListDirectory(string path, uint offset, IBufferWriter<byte> buffer, CancellationToken cancel = default)`	`Task<byte>`	Lists directory and writes raw bytes into a buffer from the remote filesystem.
`ListDirectory(string path, uint offset, IBufferWriter<char> buffer, CancellationToken cancel = default)`	`Task<byte>`	Lists directory and writes decoded characters into a buffer from the remote filesystem.
`ListDirectory(string path, uint offset, Memory<char> buffer, CancellationToken cancel = default)`	`Task<byte>`	Lists directory and writes decoded characters into a memory block from the remote filesystem.

`IFtpClient.OpenFileRead`

Parameter	Type	Description
`path`	`string`	Remote file path.
`cancel`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.OpenFileWrite`

Parameter	Type	Description
`path`	`string`	Remote file path.
`cancel`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.CreateDirectory`

Parameter	Type	Description
`path`	`string`	Remote directory path.
`cancellationToken`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.CreateFile`

Parameter	Type	Description
`path`	`string`	Remote file path.
`cancellationToken`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.ResetSessions`

Parameter	Type	Description
`cancellationToken`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.RemoveDirectory`

Parameter	Type	Description
`path`	`string`	Remote directory path.
`cancellationToken`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.RemoveFile`

Parameter	Type	Description
`path`	`string`	Remote file path.
`cancellationToken`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.CalcFileCrc32`

Parameter	Type	Description
`path`	`string`	Remote file path.
`cancellationToken`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.TruncateFile`

Parameter	Type	Description
`request`	`TruncateRequest`	Truncate request (path and offset).
`cancellationToken`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.WriteFile`

Parameter	Type	Description
`request`	`WriteRequest`	Write request (session, offset, and size).
`buffer`	`Memory<byte>`	Source buffer.
`cancellationToken`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.BurstReadFile`

Parameter	Type	Description
`request`	`ReadRequest`	Read request (session, offset, and size).
`onBurstData`	`Action<FileTransferProtocolPacket>`	Callback invoked for each received FTP packet during burst read.
`cancel`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.Rename`

Parameter	Type	Description
`path1`	`string`	Source path.
`path2`	`string`	Destination path (new name for the path).
`cancel`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.TerminateSession`

Parameter	Type	Description
`session`	`byte`	Session id.
`cancel`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.ReadFile`

Parameter	Type	Description
`request`	`ReadRequest`	Read request (session, offset, and size).
`cancel`	`CancellationToken`	Optional cancel token argument.

Parameter	Type	Description
`request`	`ReadRequest`	Read request (session, offset, and size).
`buffer`	`Memory<byte>`	Destination buffer.
`cancel`	`CancellationToken`	Optional cancel token argument.

Parameter	Type	Description
`request`	`ReadRequest`	Read request (session, offset, and size).
`buffer`	`IBufferWriter<byte>`	Destination buffer writer.
`cancel`	`CancellationToken`	Optional cancel token argument.

`IFtpClient.ListDirectory`

Parameter	Type	Description
`path`	`string`	Remote directory path.
`offset`	`uint`	Paging offset.
`cancel`	`CancellationToken`	Optional cancel token argument.

Parameter	Type	Description
`path`	`string`	Remote directory path.
`offset`	`uint`	Paging offset.
`buffer`	`IBufferWriter<byte>`	Destination buffer writer.
`cancel`	`CancellationToken`	Optional cancel token argument.

Parameter	Type	Description
`path`	`string`	Remote directory path.
`offset`	`uint`	Paging offset.
`buffer`	`IBufferWriter<char>`	Destination buffer writer.
`cancel`	`CancellationToken`	Optional cancel token argument.

Parameter	Type	Description
`path`	`string`	Remote directory path.
`offset`	`uint`	Paging offset.
`buffer`	`Memory<char>`	Destination buffer writer.
`cancel`	`CancellationToken`	Optional cancel token argument.

Last modified: 02 March 2026