Lyo.Sftp.Client 2.0.1

Lyo.Sftp.Client

SSH.NET wrapper for SFTP used by Lyo hosts and storage adapters (Lyo.FileStorage.Sftp). Call *Async from hosts (Task + CancellationToken). Those methods hit SSH.NET's async API and the await-safe pool/per-client gates. Sync methods wait on that async path. Pooled connections are leased, POSIX paths stay under RootRemoteDirectory through Lyo.Common.Core.Pathing.PathHelpers, host-key allow lists are checked, and auth is password or private key. ILogger and sftp.* metrics are recorded. Callers may run concurrently up to MaxPooledClients. Do not share one leased Stream across threads. SftpFileSystem adapts ISftpClient onto Lyo.IO.FileSystem.IFileSystem (AddSftpFileSystem).

Features

• Async. Hosts and adapters should call *Async. Sync wrappers wait on the async implementation. No Task.Run.
• Pooled leases. Up to MaxPooledClients SSH.NET clients at once. Each client serializes work across awaits with a SemaphoreSlim.
• Concurrent callers. Parallelism stops at the pool size. A single leased stream is not thread-safe.
• IFileSystem. SftpFileSystem wraps ISftpClient. Register with AddSftpFileSystem.
• Path jail. Paths stay under RootRemoteDirectory with PathStyle.Posix.
• Auth. Password and/or a PEM or key-file private key. Host-key fingerprint allow list, or AcceptAny in tests.
• Logging and metrics. ILogger and IMetrics (sftp.connect, sftp.operation, sftp.bytes, sftp.pool, sftp.errors). Turning EnableMetrics off uses NullMetrics.
• DI. AddSftpClient / AddSftpClientFromConfiguration.

Examples

DI setup

services.AddSftpClient(o =>
{
    o.Host = "sftp.example.com";
    o.Username = "lyo";
    o.Password = secret;
    o.RootRemoteDirectory = "/data/lyo";
    o.HostKeyPolicy = SftpHostKeyPolicy.FingerprintAllowList;
    o.AllowedHostKeyFingerprints.Add("SHA256:...");
});

Upload and download asynchronously

await client.UploadAsync("report.bin", bytes, ct);
var copy = await client.DownloadBytesAsync("report.bin", ct);

Dependencies

Generated from ProjectReference / PackageReference (same model as docs/Lyo.ProjectGraph.html).

• Lyo.Common.Metadata (direct, lyo)
• Lyo.Exceptions (direct, lyo)
• Lyo.IO.FileSystem (direct, lyo)
• Lyo.Metrics (direct, lyo)
• Microsoft.Extensions.Configuration.Binder 10.0.5 (direct, microsoft)
• Microsoft.Extensions.DependencyInjection.Abstractions 10.0.5 (direct, microsoft)
• Microsoft.Extensions.Logging.Abstractions 10.0.5 (direct, microsoft)
• SSH.NET 2025.1.0 (direct, third-party)
• Lyo.Common.Core (transitive, lyo)
• Microsoft.Bcl.AsyncInterfaces 10.0.5 (transitive, microsoft, netstandard2.0)
• System.Memory 4.6.3 (transitive, microsoft, netstandard2.0)
• System.Text.Json 10.0.5 (transitive, microsoft, netstandard2.0)