Bitbean.Dependencies.FtpService 1.0.15

FTP Service

A simple, focused service for downloading files from FTP/SFTP servers with support for multiple protocols.

Features

• Downloads files from SFTP servers (using SSH.NET)
• Downloads files from FTPS servers with explicit/implicit TLS/SSL encryption (using FluentFTP)
• Automatic protocol selection based on connection configuration
• Skips files that already exist locally with the same size
• Provides detailed download statistics
• Handles errors gracefully

Usage

Registration

Register the service in your Startup.cs or Program.cs:

// Add FTP service
services.AddFtpService();

Basic Usage

// Create connection info for SFTP
var sftpConnectionInfo = new FtpConnectionInfo
{
    ProtocolType = FtpProtocolType.Sftp,
    Host = "sftp.example.com",
    Username = "username",
    Password = "password",
    RemoteDirectory = "remote/directory"
    // Port will default to 22 for SFTP
};

// Create connection info for FTPS Explicit
var ftpsConnectionInfo = new FtpConnectionInfo
{
    ProtocolType = FtpProtocolType.FtpsExplicit,
    Host = "ftp.example.com",
    Username = "username",
    Password = "password",
    RemoteDirectory = "remote/directory"
    // Port will default to 21 for FTPS Explicit
};

// Download files
var result = await ftpService.DownloadFilesAsync(
    connectionInfo,
    "remote/directory",
    "local/directory",
    cancellationToken);

// Check results
Console.WriteLine($"Total files: {result.TotalFiles}");
Console.WriteLine($"Downloaded: {result.DownloadedFiles}");
Console.WriteLine($"Skipped: {result.SkippedFiles}");
Console.WriteLine($"Failed: {result.FailedFiles}");

With CompanyIntegration

If you're using the CompanyIntegration model, you can use the extension method:

// Convert from CompanyIntegration
var connectionInfo = integration.ToFtpConnectionInfo();

// Download files
var result = await ftpService.DownloadFilesAsync(
    connectionInfo,
    "remote/directory",
    "local/directory",
    cancellationToken);

Progress Tracking

Track download progress in real-time for both SFTP and FTPS with detailed metrics:

var connectionInfo = new FtpConnectionInfo
{
    ProtocolType = FtpProtocolType.Sftp,
    Host = "sftp.example.com",
    Username = "username",
    Password = "password",

    // Optional: Track download progress with detailed metrics
    ProgressCallback = progress =>
    {
        Console.WriteLine($"Progress: {progress.Progress:F1}%");
        Console.WriteLine($"Downloaded: {progress.TransferredBytes:N0} / {progress.FileSize:N0} bytes");
        Console.WriteLine($"Speed: {progress.TransferSpeedBytesPerSecond / 1024 / 1024:F2} MB/s");

        if (progress.EstimatedTimeRemaining.HasValue)
        {
            Console.WriteLine($"ETA: {progress.EstimatedTimeRemaining.Value:hh\\:mm\\:ss}");
        }

        // Update progress bar, UI, etc.
    }
};

var result = await ftpService.DownloadFileAsync(
    connectionInfo,
    "/remote/path/file.zip",
    @"C:\local\path\file.zip",
    cancellationToken);

Progress Information Available:

• Progress - Percentage complete (0-100), or -1 if unknown
• TransferredBytes - Number of bytes transferred so far
• FileSize - Total file size in bytes
• TransferSpeedBytesPerSecond - Current transfer speed
• EstimatedTimeRemaining - Estimated time to completion (nullable)
• LocalPath - Local file path being transferred
• RemotePath - Remote file path being transferred

Performance Optimization for SFTP (Large Files)

For downloading large files over SFTP, you can configure performance settings:

var sftpConnectionInfo = new FtpConnectionInfo
{
    ProtocolType = FtpProtocolType.Sftp,
    Host = "sftp.example.com",
    Username = "username",
    Password = "password",

    // Performance optimizations for large file downloads
    BufferSize = 64 * 1024,                    // 64KB buffer (default)
    DisableCompression = true,                  // Disable compression for faster transfers
    PreferredCiphers = new[] { "aes128-ctr", "aes256-ctr" }, // Prioritize CTR ciphers for high-speed NICs
    InterFileDelayMilliseconds = 0,             // No delay between files (default)

    // Optional: Track progress with detailed metrics
    ProgressCallback = progress =>
    {
        Console.WriteLine($"{progress.Progress:F1}% - {progress.TransferSpeedBytesPerSecond / 1024 / 1024:F2} MB/s");
    }
};

var result = await ftpService.DownloadFileAsync(
    sftpConnectionInfo,
    "/remote/path/large-file.sqb",
    @"C:\local\path\large-file.sqb",
    cancellationToken);

Performance Notes:

• The service uses SSH.NET's DownloadFile method which internally uses up to 100 concurrent read requests for optimal throughput
• For large files (>100MB), these optimizations can provide 3-7x performance improvement
• CTR ciphers (aes128-ctr, aes256-ctr) are optimized for high-speed network interfaces
• Disabling compression reduces CPU overhead when transferring already-compressed files
• InterFileDelayMilliseconds allows rate-limiting when downloading many files (default is 0 for maximum speed)
• ProgressCallback works for both SFTP and FTPS protocols

Moving/Archiving Files

Move files from one location to another on the remote server (useful for archiving processed files):

// Move a file to an archive directory
bool success = await ftpService.MoveFileAsync(
    connectionInfo,
    "/remote/inbox/data.csv",
    "/remote/archive/data.csv",
    cancellationToken);

if (success)
{
    Console.WriteLine("File successfully moved to archive");
}
else
{
    Console.WriteLine("Failed to move file");
}

Notes:

• The destination directory will be created automatically if it doesn't exist
• For SFTP, uses SSH.NET's RenameFile method
• For FTPS, uses FluentFTP's MoveFile method
• Returns true on success, false on failure
• Errors are logged but do not throw exceptions

Implementation Details

• Uses SSH.NET for SFTP operations with optimized download methods
• Uses FluentFTP for FTPS operations
• Implements IAsyncEnumerable for efficient file listing
• Handles connection and authentication errors
• Provides detailed logging
• Supports performance tuning for large file transfers (SFTP only)