🚀 LAN Share — Blazing Fast LAN File Explorer & Transfer

A high-performance, multi-threaded LAN file sharing tool with a live browser dashboard.
Browse any computer's files on your local network, send/receive files, and monitor everything in real time.

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Features

• Auto device discovery — UDP broadcast + active /24 subnet scanning detects devices in seconds
• Blazing fast — 64-thread pool for concurrent connections, 1 MB chunk transfers, keep-alive HTTP
• Live dashboard — Server-Sent Events push updates to the browser instantly, no polling
• File explorer — Browse any connected device's filesystem like a native file manager
• Send & receive — Transfer files to/from any device with a progress bar
• Self-browse — Works even with a single machine (browse your own files)
• 3-file architecture — server.py, state.json, dashboard.html

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Files

File	Purpose
server.py	Python backend — HTTP server, UDP discovery, file transfer engine
dashboard.html	Live browser UI — file explorer, device list, transfer tracker
state.json	Persisted state — devices seen, transfer history, stats

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Requirements

• Python 3.10+ (uses walrus operator :=)
• No external packages — 100% standard library

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Quick Start

# Clone or copy the 3 files into a folder, then:
python server.py

Open your browser to the URL printed in the terminal, e.g.:

Dashboard → http://192.168.1.42:8765/

Run the same command on every machine you want to connect.
They will discover each other automatically within a few seconds.

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How It Works

Discovery (two-layer)

1. UDP Broadcast — Every device broadcasts a LANSHARE: packet every 3 seconds on port 54321.
   Devices on the same subnet hear it instantly.

2. Active Subnet Scan — A background thread probes every IP in your /24 subnet (x.x.x.1–x.x.x.254)
   by hitting the LAN Share HTTP endpoint. New devices appear in seconds.

File Transfer

• Click a remote device in the sidebar → its filesystem opens in the explorer
• Select files → click ⇧ Send Selected → choose target device + destination folder
• Progress bars update live via SSE

Single-Device Mode

Works perfectly on one machine — browse your own files, test transfers to yourself,
or just use it as a fast local file manager in the browser.

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Configuration

Edit the constants at the top of server.py:

BASE_DIR       = Path.home()   # Root directory for browsing
HTTP_PORT      = 8765          # Web server port
DISCOVERY_PORT = 54321         # UDP broadcast port
SCAN_INTERVAL  = 5             # Seconds between network scans
BROADCAST_INT  = 3             # Seconds between presence broadcasts
MAX_WORKERS    = 64            # Thread pool size
CHUNK_SIZE     = 1 << 20      # 1 MB transfer chunks

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API Reference

All endpoints are available on every running instance.

Method	Path	Description
GET	/	Serve the dashboard
GET	/api/info	Device info (used for discovery probing)
GET	/api/state	Full JSON state snapshot
GET	/api/browse?path=<path>	List directory contents
GET	/api/download?path=<path>	Download a file
GET	/api/events	SSE stream for live updates
GET	/api/remote/browse?ip=&port=&path=	Proxy browse to remote device
POST	/api/send	Trigger upload to remote device
POST	/api/receive	Receive an uploaded file
POST	/api/delete	Delete a file or folder
POST	/api/mkdir	Create a directory

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Performance Notes

• The thread pool (MAX_WORKERS=64) handles all HTTP requests and background scans concurrently
• File transfers use chunked streaming — no full file buffering in RAM
• SSE keeps one persistent connection open per browser tab; all events are pushed zero-latency
• Subnet scanning runs 254 probe connections in parallel via ThreadPoolExecutor

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Security

⚠️ LAN only. This tool has no authentication. Anyone on your local network can browse
and download files from the directories you expose. Do not run on public/untrusted networks.

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License

MIT — use freely, modify freely.