README.md

🌐 Advanced Real-Time Collaboration System
_{A distributed networking system showcasing custom protocol implementations}

🎯 What is SyncroX?

SyncroX is a real-time collaborative and communication platform demonstrating advanced networking concepts including custom TCP protocols, Tahoe/Reno congestion control, RTT estimation, and secure Docker-based code execution — all built entirely from scratch using Python sockets. It features reliable file sharing, instant messaging with image CDN, and synchronous collaborative editing.

⚡ Key Features

📡 Reliable UDP Protocol Custom RDT 3.0+ implementation Sliding windows with cumulative ACKs Tahoe & Reno congestion control Real-time RTT estimation	💬 Real-time Chat System Custom TCP application layer protocol Image CDN with lazy loading Instant message broadcast Persistent chat history
📝 Collaborative Code Editor Live document synchronization Multi-user editing support 500ms update frequency Last-Write-Wins conflict resolution	🐳 Secure Code Execution Docker-sandboxed environment Network isolation (--network=none) Resource limits (CPU, RAM, PIDs) Ephemeral containers

📸 Screenshots

🖥️ Application Interface

🏠 Home Dashboard	📁 File Transfer
💻 Code Editor	⚡ Code Execution

📊 Congestion Control Analytics

📈 RTT vs Chunk Sequence & CWND vs Event Sequence

📈 Window Size vs Transmission Round

🏗️ Architecture

📋 Service Details

Service	Port	Protocol	Description
🖥️ Frontend	8501	HTTP	Streamlit UI Gateway
🔑 Room Manager	9013	TCP	Room lifecycle management
💬 Chat Service	9009	TCP	Messaging & image CDN
📂 File Control	9010	TCP	File listing & signaling
📡 File Data	9011	UDP	Reliable data transfer
📝 Collab Service	9011	TCP	Document synchronization
🐳 Exec Service	9012	TCP	Docker code execution

📡 Technical Deep Dives

🔧 Reliable UDP Protocol

Packet Structure (JSON over UDP)

{
  "type": "DATA",           // SYN | SYN-ACK | ACK | DATA | FIN | FIN-ACK
  "seq": 105,               // Sequence Number
  "ack": 105,               // Acknowledgement Number
  "rwnd": 64,               // Receiver Window Size
  "room": "ABCD",           // Room context
  "filename": "doc.pdf",    // File context
  "payload_b64": "...",     // Base64 encoded chunk (4KB)
  "session_id": "a1b2c3d4"  // Session token
}

RTT Estimation (Jacobson/Karels)

Parameter	Formula	Value
Smoothed RTT	(1-α)·SRTT + α·RTTsample	α = 0.125
RTT Variance	`(1-β)·RTTVAR + β·	SRTT - RTTsample
RTO	SRTT + 4·RTTVAR	Min: 200ms

Congestion Control

Event	Tahoe 🐢	Reno 🦊
Timeout	CWND = 1, Slow Start	Same
3 Dup ACKs	CWND = 1, Slow Start	CWND = ssthresh + 3, Fast Recovery

💬 TCP Chat Protocol

Command Reference

Command	Direction	Description
HELLO <user> <room>	C → S	Join room
MSG <content>	C → S	Send message
IMG <filename> <b64>	C → S	Upload image
GET_IMG <filename>	C → S	Fetch image
BYE	C → S	Disconnect

CDN Lazy Loading

Step	Action	Description
1	📤 Broadcast	Server sends metadata only
2	🖼️ Render	Client shows placeholder
3	📥 Fetch	On-demand binary request
4	💾 Cache	Store in backend/data/cdn/

🛡️ Docker Security Profile

Flag	Value	Purpose
--network	none	Total network isolation
--memory	256m	Prevent RAM exhaustion
--cpus	0.5	Fair CPU scheduling
--pids-limit	64	Prevent fork bombs
--rm	true	Auto-cleanup containers

🚀 Quick Start

Prerequisites

✅ Python 3.10+     (required for match-case syntax)
✅ Docker Desktop   (must be running for code execution)
✅ pip              (for dependency management)

Installation

# Clone the repository
git clone https://github.com/Abs-Futy7/SyncroX.git
cd SyncroX

# Create virtual environment
python -m venv venv
source venv/bin/activate  # Windows: venv\Scripts\activate

# Install dependencies
pip install -r requirements.txt

# Build Docker image
docker build -t syncro-sandbox ./backend/code_exec/

# Start servers
python start_all_servers_venv.py

# Launch frontend (new terminal)
streamlit run frontend/streamlit_app/app.py

⚠️ Note: Ensure Docker Desktop is running before starting the servers.

Verify Installation

Step	Action	Expected
1	Click "Create New Room"	4-digit code appears
2	Open new tab, enter code	Join as second user
3	Send chat message	Instant delivery
4	Upload file	See congestion graph
5	Run code	Docker execution works

📁 Project Structure

SyncroX/
├── 📂 backend/
│   ├── 📂 code_exec/          # 🐳 Docker execution engine
│   ├── 📂 collab/             # 📝 Collaborative editor
│   ├── 📂 file_transfer/      # 📡 UDP file transfer
│   ├── 📂 room_mgmt/          # 🔑 Room management
│   └── 📂 tcp_chat/           # 💬 Chat protocol
├── 📂 frontend/               # 🖥️ Streamlit UI
├── 📂 App_Screenshots/        # 📸 Screenshots
├── 📂 assets/                 # 🎨 Branding
├── 📄 config.py               # ⚙️ Configuration
├── 📄 requirements.txt        # 📦 Dependencies
└── 📄 start_all_servers_venv.py  # 🚀 Launcher

👨‍💻 Authors

        

H.M. Mehedi Hasan   •   MD. Abu Bakar Siddique

 

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Built with ❤️ using Python Sockets & Streamlit

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