File history and versioning

TagBites.IO can expose previous versions of a file as FileVersionLink objects, if the underlying file system supports it. None of the built-in providers (Local, Virtual, FTP, SFTP, HTTP, ZIP, Dropbox, Google Cloud Storage, S3) implement this - it is an opt-in capability for a custom file system whose operations implement IFileSystemHistoryOperations (and, optionally, IFileSystemAsyncHistoryOperations for the asynchronous equivalents).

Listing and restoring versions

// fileSystem is a custom file system whose operations implement IFileSystemHistoryOperations.
var file = fileSystem.GetFile("file.txt");

IList<FileVersionLink> versions = file.GetHistoryVersions();
var lastWeek = versions.FirstOrDefault(v => v.ModifyTime >= DateTime.Now.Date.AddDays(-7));

lastWeek?.Restore(); // overwrites file.txt with this version's content

Asynchronous equivalents are available as GetHistoryVersionsAsync() and RestoreAsync().

FileVersionLink members

Member	Description
Source	The FileLink this version belongs to.
ModifyTime	The modification time identifying this version.
Length, Hash	Size and hash of this version’s content.
Read() / ReadAsync()	Opens a read-only stream on this version’s content.
Restore() / RestoreAsync()	Overwrites the source file with this version’s content.
Delete() / DeleteAsync()	Deletes this version from the history.
CanRead, CanWrite	Whether this version can be read/written, per IFileSystemHistoryOperations.HasReadAccess/HasWriteAccess.

A version can also be copied to an arbitrary destination like any other file link, e.g. lastWeek.Copy(otherFile, overwrite: true), instead of restoring it in place.