📡 MultiShare

A fast, secure, and easy way to transfer files between devices on the same local network—no internet connection or account required.

✨ Features

Feature	Description
🔌 Local Network Only	All transfers stay on your WiFi—never touch the internet
🚫 No Accounts	Start sharing instantly—no login, no registration
📱 QR Code Sharing	Scan to connect devices quickly
⚡ High-Speed Transfer	Stream files at full LAN speed (50-200 MB/s)
📊 Live Progress	Real-time transfer progress with speed display
✅ Integrity Check	SHA256 checksum verification
📲 PWA Support	Install as a native app on any device
🔒 Privacy First	Sessions expire after 1 hour, no logs retained

🔄 How It Works

sequenceDiagram
    participant S as Sender
    participant R as Receiver
    participant B as Backend

    Note over S,R: Both devices on same WiFi

    S->>B: 1. Select files & create session
    B-->>S: Returns session_id & share URL

    S->>R: 2. Share URL/QR Code
    R->>B: 3. Open URL, join session
    B-->>R: Show receiver UI + QR for sender

    S->>B: 4. Scan receiver's QR
    B-->>B: 5. WebSocket pairing
    B-->>S: Receiver connected!
    B-->>R: Transfer starting!

    S->>R: 6. File stream (chunked)
    R->>B: 7. Progress updates
    B-->>S: Transfer complete

Loading

Transfer Flow

┌─────────────┐     ┌─────────────┐     ┌─────────────┐
│   SENDER    │────►│   SERVER   │────►│  RECEIVER   │
│             │     │  (Flask +  │     │             │
│ 1. Pick     │     │  SocketIO) │     │ 3. Open URL │
│    files    │     │             │     │    & join   │
└─────────────┘     └─────────────┘     └─────────────┘
                           │                   │
                           │ 4. Pair via      │
                           │    WebSocket     │
                           ▼                   ▼
                    ┌─────────────┐     ┌─────────────┐
                    │ 5. Stream   │────►│ 6. Download │
                    │    files    │     │    files   │
                    │ (4MB chunks)│     │ + verify   │
                    └─────────────┘     └─────────────┘

🚀 Quick Start

Prerequisites

• Python 3.8+
• A local network (WiFi)

Installation

# Clone or download the project
cd MultiShare/backend

# Create virtual environment (recommended)
python -m venv venv
# Windows
venv\Scripts\activate
# Linux/Mac
source venv/bin/activate

# Install dependencies
pip install -r requirements.txt

Run the App

python app.py

Expected output:

🚀 MultiShare starting...
📱 Open on sender:   http://192.168.1.5:5000
📥 Receiver visits:  http://192.168.1.5:5000

Usage Guide

1. Open in Browser — Visit http://<your-ip>:5000 on both devices
2. Send Files — Click "Send Files", select files, share the link/QR
3. Receive Files — Open the shared link or scan QR code
4. Confirm Transfer — Review and confirm on the sender side
5. Download — Files stream directly to receiver with progress

📊 Performance

Metric	WiFi 5	WiFi 6
Transfer Speed	50-100 MB/s	100-200 MB/s
Connection Time	< 2s	< 2s
RAM Usage	< 100 MB	< 100 MB

🛠️ Tech Stack

┌─────────────────────────────────────────────────┐
│                  Frontend                       │
│   HTML5  •  CSS3  •  JavaScript  •  Socket.IO  │
└─────────────────────────────────────────────────┘
                         │
                         ▼
┌─────────────────────────────────────────────────┐
│                   Backend                       │
│   Flask  •  Flask-SocketIO  •  Python 3.8+     │
└─────────────────────────────────────────────────┘
                         │
                         ▼
┌─────────────────────────────────────────────────┐
│              Network Layer                      │
│   HTTP (transfers)  •  WebSocket (signaling)   │
└─────────────────────────────────────────────────┘

Dependencies

• Flask — Web framework
• Flask-SocketIO — Real-time communication
• qrcode[pil] — QR code generation
• Pillow — Image processing
• eventlet — Async I/O

📁 Project Structure

MultiShare/
├── backend/
│   ├── app.py              # Main Flask + SocketIO server
│   ├── config.py           # Port, chunk size, session TTL
│   ├── requirements.txt    # Python dependencies
│   └── utils/
│       ├── network.py      # Local IP detection
│       ├── session.py      # In-memory session management
│       └── file_handler.py # Chunked streaming + checksums
│
├── frontend/
│   ├── templates/
│   │   ├── index.html      # Landing page
│   │   ├── send.html       # File sender UI
│   │   └── receive.html    # File receiver UI
│   └── static/
│       ├── css/style.css   # Responsive styles
│       ├── js/main.js      # Client-side logic
│       ├── sw.js           # Service worker (PWA)
│       └── manifest.json   # PWA manifest
│
├── README.md
└── LICENSE

🔐 Security

• Local Network Only — All traffic stays within your LAN
• Auto-Expiring Sessions — Sessions expire after 1 hour
• Random Session IDs — Unguessable UUIDs prevent unauthorized access
• Checksum Verification — SHA256 ensures file integrity
• No Persistent Storage — No logs or files retained after transfer

🌍 Cross-Platform Support

Platform	Method
Windows	Native Python
macOS	Built-in Python3
Linux	System Python
Android	Termux
iOS	Pythonista / a-Shell

📝 License

This project is licensed under the MIT License — see the LICENSE file for details.

🤝 Contributing

Contributions are welcome! Feel free to open issues or submit pull requests.