localsend-nas

A LocalSend node with a web UI, built for NAS-style deployments: browse host-mounted share directories in a browser, assemble a basket of files, pick a discovered device, and the server sends the files directly to the recipient's LocalSend app — the files never round-trip through your laptop. Receiving works too: a desktop-app-style dialog lets you accept inbound files straight into a share.

Speaks LocalSend Protocol v2.2 over HTTPS (port 53317 by default) and announces itself via multicast, so it shows up in other devices' lists.

Receiving

On by default. When a device sends files to the NAS, every open UI tab pops a dialog with the sender, file list, a destination picker (any configured share), and a countdown (default 30 s):

• Accept / Decline — your call, per transfer.
• Countdown expires — with a dropbox configured, files are auto-accepted into that share; otherwise the request is politely rejected.
• --read-only (env LOCALSEND_NAS_READ_ONLY=1) — restores the strict v1 send-only posture: no receiving at all (senders get a clean 403).

Countdown length and the dropbox share live in the settings menu (gear icon, top right) and persist server-side in <data-dir>/settings.json. The menu also has a toggle for showing NAS metadata files (@eaDir, .DS_Store, #recycle, …) — hidden by default.

Received files keep their folder structure, never overwrite existing files (name (1).ext dedupe), and land in shares as normal files — browsable and re-sendable immediately.

Single static Go binary, no runtime dependencies, embedded web UI.

Running

Binary (see releases):

localsend-nas --listen :80 --share movies=/srv/movies --share books=/srv/books

Docker (alexindigo/localsend-nas on Docker Hub — also on GHCR; Docker Hub is the one Synology Container Manager can browse):

docker run -d --name localsend-nas --network host \
  -v /volume1/movies:/srv/movies:ro \
  -v /volume1/books:/srv/books:ro \
  -v localsend-nas-data:/data \
  -e PUID=1026 -e PGID=100 \
  -e LOCALSEND_NAS_SHARES="movies=/srv/movies,books=/srv/books" \
  alexindigo/localsend-nas:latest

(Volume syntax is -v host-path:container-path; shares stay read-only in the container. On PUID/PGID see the permissions note below.)

--network host is recommended: LocalSend discovery rides multicast UDP 53317, which NAT/bridge networking breaks. All flags have LOCALSEND_NAS_* env equivalents (--listen → LOCALSEND_NAS_LISTEN, repeatable --share → comma-separated LOCALSEND_NAS_SHARES, …).

docker-compose equivalent:

services:
  localsend-nas:
    # use `alexindigo/localsend-nas` for the Docker Hub based image
    image: ghcr.io/alexindigo/localsend-nas:latest
    container_name: localsend-nas
    network_mode: host          # required for multicast discovery
    restart: unless-stopped
    environment:
      # Your host user's uid/gid (`id` over SSH; Synology default user is
      # typically 1026:100). DSM's permission-manager abstraction doesn't
      # exist inside containers, but the underlying POSIX ACLs are enforced
      # by the kernel — the process's uid/gid must match the grant.
      PUID: "1026"
      PGID: "100"
      LOCALSEND_NAS_SHARES: movies=/srv/movies,books=/srv/books
      # LOCALSEND_NAS_LISTEN: ":8080"   # image default; :80 needs root
      # LOCALSEND_NAS_ALIAS: "Nas living-room"
    volumes:
      # host path : container path  (shares stay read-only inside the container)
      - /volume1/movies:/srv/movies:ro
      - /volume1/books:/srv/books:ro
      - localsend-nas-data:/data      # named volume for the persistent device identity

volumes:
  localsend-nas-data:

With network_mode: host the web UI lands on the host's port 8080 directly; change LOCALSEND_NAS_LISTEN if that clashes.

Permissions: the image follows the linuxserver.io PUID/PGID convention — the container starts as root, renumbers the built-in localsend user, then drops privileges. Defaults are 1000/1000; set them to the uid/gid that owns your shares (id on the host). The app never writes to :ro mounts; received files land owned by that uid/gid.

Operability (for scripts and monitoring)

• GET /api/health — liveness + identity: {"version","protocol","alias","fingerprint","lsPort"}. Always 200 when the process serves HTTP.
• GET /api/selftest — subsystem diagnostics: share roots re-stat'd, LocalSend port self-dial, multicast listener state, known-device count. 200 {"ok":true,…} when healthy, 503 with per-check error strings otherwise — so curl -sf …/api/selftest works as an install gate.

Status

Early development. See the commit history and the plan document for scope.

Logo: web/logo.svg (source) / web/logo.png (rendered) — the LocalSend "device + broadcast ring" motif, squared: a NAS box at the center of the local network. Style derived from the LocalSend logo (© Tien Do Nam, Apache-2.0) as an ecosystem homage — this is not an official LocalSend project.

License

GNU Lesser General Public License v3.0 (LGPL-3.0). See LICENSE.