v5.9.0 — Resolve file name & size without downloading

Downloader v5.9.0

✨ Resolve a remote file's name and size — without downloading it

This release exposes the engine's internal "what is this remote file?" logic as a clean public API, so you can preview a file's name and size (and whether it supports ranged/resumable downloads) from a single lightweight header probe — no need to start and immediately stop a real download just to learn its name. Perfect for populating a queue/grid of pending downloads.

// Just the name (resilient — falls back to the URL name on a network/server error):
string name = await RemoteFileResolver.GetFileNameAsync(url);

// Full metadata in one probe:
RemoteFileInfo info = await RemoteFileResolver.GetFileInfoAsync(url);
// info.FileName, info.FileSize (-1 if unknown), info.SupportsRange, info.Address (final, post-redirect)

Both methods accept an optional DownloadConfiguration (headers, proxy, credentials, cookies, redirect policy) and a CancellationToken.

🆕 What's new

• RemoteFileResolver (new public static helper) — GetFileNameAsync(url) and GetFileInfoAsync(url) returning the new RemoteFileInfo record { FileName, FileSize, SupportsRange, Address }. Name resolution: Content-Disposition → URL path → GUID. Size: Content-Range → Content-Length.
• IDownloadService.GetFileInfoAsync(url) — the same lookup on the download service, using that service's configuration, without disturbing any download in progress.

🔧 Internal

• Filename/size/range resolution is now unified behind the canonical SocketClient.GetFileInfoAsync, consumed by both the download pipeline (DownloadService) and RemoteFileResolver — removing duplicated probing logic.
• No behavior change to existing downloads (verified against the full test suite: 165 regression tests + new resolver tests, green on .NET 8/9/10).

📦 Install

dotnet add package Downloader --version 5.9.0

Full Changelog: v5.8.1...v5.9.0