Peer‑to‑peer file sync over QUIC with Merkle‑based delta transfers. Fast, safe, offline P2P sync with a clean Web UI and CLI. Transfers only changed chunks, resumes after interruptions, and verifies integrity before making changes visible.
- QUIC transport (quinn) + TLS (rustls), single UDP port
- Fixed‑size chunking (1 MiB) with Merkle trees for delta sync
- Atomic staging + verification before finalize (no partial/corrupt files)
- Resume partial transfers (chunk‑level bitmaps)
- TOFU trust pinning (accept‑first or pinned fingerprint)
- Continuous sync: Connect runs repeated passes (near real-time)
- Parallel chunk streams per file (configurable), optional global rate limiting
- Excludes internal artifacts: .leafsync_tmp, .leafsync_trash, .git, and *.part
- Web UI:
- Folder/file picker with Windows quick links (Desktop/Downloads/Documents/Pictures/Music/Videos/Home)
- “Select File” support in Serve, Connect, and Watch (single‑file sync)
- Live status with per‑file progress bar and MB/s speed
- Polished, consistent control sizing
- Optional “Mirror deletes” for Connect/Watch (safe delete: move local‑only files to .leafsync_trash)
- Streams and rate limit inputs for quick performance tuning
- Launch the UI
cargo run -- ui --port 8080- Open http://127.0.0.1:8080 and use the cards:
- Serve a folder
- Pick a folder to expose. Optional: click “Browse…” and “Select File” to serve only one file.
- Connect to a peer
- Enter peer IP:port and choose your local destination folder.
- Optional: pick a specific file to sync (relative to the chosen folder).
- First time: check “Accept first” to pin the server fingerprint automatically.
- Connect runs continuously; leave it open for near real-time sync.
Notes
- The picker lets you browse directories and also select a file. When you click “Select File”, the folder field is set to the current directory and the file field is populated with a relative path.
- On Windows, the picker shows quick links (Desktop, Downloads, Documents, Pictures, Music, Videos, Home).
The CLI supports single‑file sync and mirror deletes flags. Connect runs continuously.
# Start a server (listener)
cargo run -- serve .\shared --port 4455 [--file relative\\path\\to\\file]
# Connect to a server and sync (first time: trust on first use)
cargo run -- connect 127.0.0.1:4455 .\shared --accept-first [--fingerprint <hex>] [--file relative\\path\\to\\file] [--mirror] [--streams 8] [--rate-mbps 50]
# Connect runs continuous sync passes until you stop it
# Manage trusted fingerprints (TOFU store)
cargo run -- trust list
cargo run -- trust add 127.0.0.1:4455 <hex-fingerprint>
cargo run -- trust remove 127.0.0.1:4455Tips
- After the first successful connect, the fingerprint is pinned and reused.
- Allow UDP on your chosen port in Windows Firewall.
- Mirror deletes is safe by design: instead of hard‑deleting, it moves local‑only files into a timestamped folder under .leafsync_trash so you can undo.
- Internal paths are ignored automatically: .leafsync_tmp/, .leafsync_trash/, .git/, and any *.part staging files.
- Summary + diff
- Server summarizes files; client requests per‑file metadata (chunk hashes).
- Client diffs by chunk index and requests only missing/different chunks.
- Transfer
- Chunks stream over a QUIC bidirectional stream with length‑prefixed, bincode‑encoded messages.
- Integrity + atomic finalize
- Chunks write to a staging path; the Merkle root is recomputed and verified.
- On success, the staged file is atomically renamed into place.
- Resume
- If interrupted, the next session requests only the missing chunk indices.
- Watch
- Debounced local changes trigger a sync; a periodic pull catches remote‑only edits.
- Sends only what changed
- Merkle‑based, fixed‑size chunk diffs avoid re‑sending whole files; ideal for large binaries and VM images.
- Robust on flaky links
- QUIC multiplexing avoids TCP head‑of‑line blocking; per‑chunk resume skips already‑received data after interruptions.
- Safe writes
- Atomic staging + verification prevents corrupt or partially written files from replacing good ones.
- Low ceremony peer trust
- TOFU pinning gives encrypted, authenticated connections without a CA or external service.
- Practical UX
- Built‑in Web UI, real‑time progress/speed, and a native‑feeling picker with Windows quick folders.
- Bandwidth efficiency
- Only changed chunks transfer; unchanged chunks are skipped entirely.
- Latency tolerance
- QUIC avoids head‑of‑line blocking; a lost packet doesn’t stall the whole stream.
- Disk I/O
- Chunk‑aligned writes to a staging file reduce random I/O on finalize.
- Resume at scale
- Chunk bitmaps prevent re‑downloading already received data after a drop or restart.
- Single‑file mode
- Targeting one file reduces metadata exchange and scanning overhead.
- Practical tuning
- Streams: 4–8 on LAN works well; up to 16 on high‑latency links. Increase gradually.
- Rate limit: set --rate-mbps to avoid saturating shared links.
- Run on wired/LAN or strong Wi‑Fi for peak throughput.
- Exclude large caches/temp folders via .leafsyncignore to reduce scanning.
- When enabled on Connect/Watch, files present locally but missing on the server are moved to:
- /.leafsync_trash//
- Only the local side is affected; the server’s folder is not pruned.
- Restore by moving files back from .leafsync_trash.
- Self‑signed TLS with certificate fingerprint pinning (TOFU).
- Use
--accept-firstonly in trusted environments; fingerprints persist locally. - No external servers or cloud dependency for LAN/Wi‑Fi usage.
- Timeout on connect
- Ensure the server is running and Windows Firewall allows UDP on the chosen port.
- File looks unchanged after shrink
- Atomic finalize truncates staged files to the exact size before rename; re‑run connect if needed.
- Watch doesn’t fire
- Confirm Watch is started on the correct local folder; .leafsyncignore may exclude the path.
- “Push verify failed” on server during uploads
- Fixed by seeding the server’s staging from existing destination before applying deltas. Update to latest build.
- Also ensure internal folders are excluded; don’t place data under .leafsync_tmp or .leafsync_trash.
- Cross‑file parallelism and parallel uploads
- mDNS peer discovery + UPnP mapping
- Mirror retention policy and history view; optional true delete
- Conflict detection/resolve UX
- Mobile apps (Android/iOS)