Lyo.IO.FileSystem 3.0.0

Lyo.IO.FileSystem

Path-rooted virtual file system. Callers use IFileSystem. LocalFileSystem and MemoryFileSystem ship in this package. SFTP, FTP, S3, Azure Blob, and FileSystemWatcher implement the same contract in their existing packages. FileStorage uses IFileSystem only for physical keys (IFileStoragePhysical), not as a catalog. Paths stay under RootPath through Lyo.Common.Core.Pathing.PathHelpers.

Features

• Contract. IFileSystem lists, reads, writes, copies, and moves files, and resolves a relative path against RootPath. Async is canonical; sync methods park (same pattern as Lyo SFTP/FTP clients). Missing paths throw FileNotFoundException, a refused overwrite throws IOException, and an unsupported capability throws NotSupportedException on every backend.
• Metadata in one call. GetEntry / GetEntryAsync return a FileSystemEntry? (kind, length, last write) instead of chaining FileExists, GetLength, and GetLastWriteTimeUtc. EnumerateDirectoryAsync streams a directory, optionally recursively, without materialising the listing.
• Capabilities. FileSystemCapabilities flags (Read, Write, CreateDirectory, Delete, Move, Copy, Watch, Append, MoveDirectory). Object stores clear Append and MoveDirectory; Watch returns null when watching is not supported.
• Local disk. LocalFileSystem (PathStyle.Host) jailed to a root directory, with one stat per metadata call, a single-pass directory listing, and async-capable streams from the async openers. CreateRootIfMissing controls whether the root is created on construction.
• Memory. MemoryFileSystem (PathStyle.Posix) on a flat path map plus a child index, guarded by a ReaderWriterLockSlim. Point lookups stay O (1), listing is O (children) rather than O (store), and append, create, move, and subtree delete are atomic. Fits WASM and tests.
• Helpers. FileSystemExtensions for ReadAllBytes / ReadAllText, TouchFile, WriteAllBytes / WriteAllText / AppendAllText (including ReadOnlyMemory<byte> overloads), CopyStreamToFileAsync, and EnsureDirectoryAccessible. IFileTreeSource is a list-only seam for tree UIs (including HTTP).
• Shared contract suite. Lyo.IO.FileSystem.Tests exposes IFileSystemContractTests, which every in-repo backend derives from so the sync and async halves of the interface are held to the same behaviour.
• DI. AddLocalFileSystem / AddMemoryFileSystem / AddLocalFileSystemFromConfiguration / AddFileTreeSource.

Examples

Local disk

services.AddLocalFileSystem(o => o.RootPath = "/var/lyo-data");

var fs = new LocalFileSystem("/tmp/lyo");
fs.CreateDirectory(Path.Combine(fs.RootPath, "reports"));
fs.WriteAllBytes(Path.Combine(fs.RootPath, "a.bin"), payload);

In-memory

services.AddMemoryFileSystem();

var fs = new MemoryFileSystem();
fs.WriteAllText("/note.txt", "hello");

if (await fs.GetEntryAsync("/note.txt", ct) is { IsDirectory: false } entry)
    Console.WriteLine($"{entry.Length} bytes, written {entry.LastWriteTimeUtc:O}");

Dependencies

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

• Lyo.Common.Core (direct, lyo)
• Lyo.Exceptions (direct, lyo)
• Microsoft.Bcl.AsyncInterfaces 10.0.5 (direct, microsoft, netstandard2.0)
• Microsoft.Extensions.Configuration.Binder 10.0.5 (direct, microsoft)
• Microsoft.Extensions.DependencyInjection.Abstractions 10.0.5 (direct, microsoft)
• System.Memory 4.6.3 (transitive, microsoft, netstandard2.0)
• System.Text.Json 10.0.5 (transitive, microsoft, netstandard2.0)