Remote Control Application - Project Nhập Môn Lập Trình

A remote desktop control application for Windows machines on LAN using Java, TCP/IP sockets, and JSON messaging.

📚 Overview

This is a learning project demonstrating computer network concepts through building a remote control application. The project consists of:

Client Application: GUI to control a remote machine
Server Application: Executes commands from client on a remote machine

Both communicate via TCP/IP sockets using JSON message format over LAN (Local Area Network).

✨ Features

Core Features

✅ List/Start/Stop Applications
✅ List/Start/Stop/Kill Processes
✅ Screenshot Capture
✅ Keylogger
✅ File Transfer (Upload/Download)
✅ System Control (Shutdown/Restart)
✅ Webcam Stream
✅ Network Monitoring

Advanced Features

✅ Remote Desktop
✅ System Lock (freeze input)
✅ Network Performance Metrics (bandwidth, latency)
✅ Real-time logging

🏗️ Architecture

┌─────────────────────────────────────────────────────┬─────────────────┐
│                   CLIENT MACHINE                    │  SERVER MACHINE │
├─────────────────────────────────────────────────────┼─────────────────┤
│                                                     │                 │
│  ┌─────────────────────────────────────┐           │                 │
│  │   ClientUI (Swing)                  │           │                 │
│  │  ┌─ Application Tab                 │           │                 │
│  │  ├─ Process Tab                     │           │                 │
│  │  ├─ Screenshot Tab                  │           │                 │
│  │  ├─ Keylogger Tab                   │           │                 │
│  │  ├─ File Transfer Tab               │           │                 │
│  │  ├─ System Control Tab              │           │                 │
│  │  ├─ Webcam Tab                      │           │                 │
│  │  ├─ Network Monitor Tab             │           │                 │
│  │  ├─ Remote Desktop Tab              │           │                 │
│  │  ├─ System Lock Tab                 │           │                 │
│  │  └─ Log Window                      │           │                 │
│  └─────────────────────────────────────┘           │                 │
│           │                                        │                 │
│           ↓                                        │                 │
│  ┌──────────────────────────────────┐             │                 │
│  │   ClientCore (Socket Connection) │             │                 │
│  └──────────────────────────────────┘             │                 │
│           │                                        │                 │
│           ↓                                        │                 │
│  ────────────[TCP Socket - Port 8888]──────────↓  │                 │
│           ↑                                        │    ┌────────────┴──────┐
│           │                         Connection    │    │                   │
│           └────────────────────────────────────────│──→ │ ServerCore       │
│                                                     │    │ (Accept)         │
│                                                     │    └─────────┬────────┘
│                                                     │            │
│                                                     │    ┌───────┴─────────┐
│                                                     │    │ MessageRouter   │
│                                                     │    └───────┬─────────┘
│                                                     │            │
│                                                     │    ┌───────┴─────────────────────┐
│                                                     │    │                             │
│                                                     │  Handlers:                      │
│                                                     │  ├─ ApplicationHandler          │
│                                                     │  ├─ ProcessHandler              │
│                                                     │  ├─ ScreenCaptureHandler       │
│                                                     │  ├─ KeyloggerHandler           │
│                                                     │  ├─ FileTransferHandler        │
│                                                     │  ├─ SystemControlHandler       │
│                                                     │  ├─ WebcamHandler              │
│                                                     │  ├─ NetworkMonitorHandler      │
│                                                     │  ├─ RemoteDesktopHandler       │
│                                                     │  └─ SystemLockHandler          │
│                                                     │                                 │
└─────────────────────────────────────────────────────┴─────────────────────────────────┘

🔌 Protocol & Messaging

Connection

Protocol: TCP/IP (Transmission Control Protocol)
Port: 8888 (configurable)
Connection Type: Persistent, full-duplex
Format: Length-prefix framing + JSON

Message Structure

{
  "type": "REQUEST|RESPONSE|STREAM|ERROR|HEARTBEAT",
  "action": "LIST_APPS|SCREENSHOT|KILL_PROCESS|...",
  "requestId": "uuid-string",
  "timestamp": 1234567890,
  "data": { ... }
}

Protocol Stack

┌──────────────────────────────┐
│  Application Layer           │  JSON Messages
│  (Commands & Data)           │
├──────────────────────────────┤
│  Length-Prefix Framing       │  [4 bytes length][N bytes data]
├──────────────────────────────┤
│  TCP Socket Layer            │  Reliable, ordered, 8888
├──────────────────────────────┤
│  IP Layer                    │  Routing within LAN
├──────────────────────────────┤
│  Link Layer                  │  Ethernet/WiFi
└──────────────────────────────┘

📦 Project Structure

nhap_mon_lap_trinh/
├── src/
│   ├── common/                           # Shared code
│   │   ├── Message.java                  # Message class
│   │   ├── MessageType.java              # Message types enum
│   │   ├── ActionType.java               # Action types enum
│   │   ├── Constants.java                # Global constants
│   │   ├── LogManager.java               # Logging utilities
│   │   └── NetworkUtils.java             # Network utilities
│   │
│   ├── client/                           # Client application
│   │   ├── ClientMain.java               # Entry point
│   │   ├── ClientCore.java               # Socket connection
│   │   ├── controllers/                  # Business logic (10 controllers)
│   │   └── ui/
│   │       ├── ClientUI.java             # Main window
│   │       └── tabs/                     # 10 tabs (1 per feature)
│   │
│   └── server/                           # Server application
│       ├── ServerMain.java               # Entry point
│       ├── ServerCore.java               # Socket listener
│       ├── MessageRouter.java            # Route messages to handlers
│       ├── handlers/                     # 10 feature handlers
│       └── ui/
│           └── ServerUI.java             # UI + logging
│
├── .github/
│   └── workflows/
│       └── build-and-package.yml         # GitHub Actions CI/CD
│
├── scripts/
│   ├── package.ps1                       # PowerShell packaging script
│   ├── package.bat                       # Batch packaging script
│   └── package.sh                        # Bash packaging script
│
├── build.bat & build.sh                  # Quick build commands
├── pom.xml                               # Maven configuration
├── BUILD_GUIDE.md                        # Build instructions
├── GITHUB_ACTIONS_GUIDE.md               # CI/CD documentation
└── README.md                             # This file

🚀 Quick Start

Prerequisites

Java 11+ (Download: https://adoptium.net/)
Maven 3.6+ (Download: https://maven.apache.org/)
Windows OS (some features are Windows-specific)
Network: Both machines on same LAN

Build Locally

Windows:

.\build.bat

Mac/Linux:

bash build.sh

This will:

✅ Compile source code with Maven
✅ Create remote-client.jar and remote-server.jar
✅ Package into remote-client.zip and remote-server.zip

Run Application

Extract ZIP files and run:

# Client
java -jar remote-client.jar

# Server
java -jar remote-server.jar

Or use provided launchers:

# Windows
cd remote-client
run.bat

cd remote-server
run.bat

Configure Connection

In Client: Edit config.properties

server.host=192.168.1.100    # Server IP on LAN
server.port=8888              # Server port

Start Server first
Start Client and connect

🔨 Build System

Maven

Language: Java 11
Build Tool: Apache Maven
Plugins Used:
- maven-compiler-plugin: Compile source code
- maven-assembly-plugin: Create JARs with dependencies

Output

target/remote-client.jar: Client executable (~50MB with dependencies)
target/remote-server.jar: Server executable (~50MB with dependencies)

🤖 Continuous Integration / Continuous Deployment

GitHub Actions automatically builds and packages on every push:

Triggers

✅ Push to main, master, or develop branches
✅ Pull Requests
✅ Manual trigger (GitHub Actions tab)

Artifacts

Download from GitHub Actions → Artifacts:

remote-client-package (ZIP)
remote-server-package (ZIP)

See GITHUB_ACTIONS_GUIDE.md for details.

📚 Learning Outcomes

This project teaches:

Network Programming
- TCP/IP socket communication
- Client-server architecture
- Protocol design (Length-prefix framing)
- Message serialization (JSON)
Java Concepts
- Object-oriented design
- Multi-threading (ExecutorService)
- Exception handling
- File I/O
- Java Swing GUI
Software Engineering
- Project structure & organization
- Documentation
- Build automation (Maven)
- CI/CD (GitHub Actions)
- Version control (Git)
System Integration
- Process management (Windows)
- Screenshot capture
- Keyboard/mouse input handling
- Webcam integration
- Registry access

🔐 Security Notes

⚠️ This is a learning project, not production-ready!

Security considerations:

❌ No encryption (data sent in clear text)
❌ No authentication (anyone can connect)
❌ No authorization (no role-based access)
❌ Vulnerable to man-in-the-middle attacks

For production:

✅ Add SSL/TLS encryption
✅ Implement authentication (username/password or certificates)
✅ Add authorization (role-based control)
✅ Rate limiting
✅ Input validation & sanitization
✅ Audit logging

🐛 Troubleshooting

"Java not found"

→ Install Java 11+ from https://adoptium.net/

"Maven not found"

→ Install Maven from https://maven.apache.org/

Build fails

→ Check BUILD_GUIDE.md troubleshooting section

Cannot connect client to server

→ Ensure:

Server is running
Both machines on same LAN
Firewall allows port 8888
Client configured with correct server IP

GUI is not responsive

→ Check if server is running and responding → Look at logs for errors

📖 Documentation

BUILD_GUIDE.md: Detailed build instructions
GITHUB_ACTIONS_GUIDE.md: GitHub Actions CI/CD setup
log.md: Original project requirements & discussion

🎓 Author Notes

Project for "Nhập Môn Lập Trình" (Introduction to Programming) course

Goal: Build a remote control application to understand:

Network protocols (TCP/IP)
Client-server architecture
Multi-threading & concurrency
Message protocol design
Software project organization

Constraints:

Keep it simple for learning
Well-documented code
Minimal dependencies
Cross-platform where possible

📈 Future Enhancements

Possible extensions (beyond scope of current project):

📞 Support

For questions or issues:

Check BUILD_GUIDE.md
Check GITHUB_ACTIONS_GUIDE.md
See original discussion in log.md

⚙️ Tech Stack

Component	Technology
Language	Java 11
Build Tool	Apache Maven
Network	TCP/IP Sockets
Messaging	JSON (org.json library)
GUI	Java Swing
CI/CD	GitHub Actions
Version Control	Git
Platform	Windows (Primary)

📄 License

Educational project - Use for learning purposes

Last Updated: 2026-04-19
Status: ✅ Active Development

Name		Name	Last commit message	Last commit date
Latest commit History 33 Commits
.github/workflows		.github/workflows
scripts		scripts
src		src
.gitignore		.gitignore
README.md		README.md
build.bat		build.bat
build.sh		build.sh
compile.bat		compile.bat
compile.sh		compile.sh
launch4j-client.xml		launch4j-client.xml
launch4j-server.xml		launch4j-server.xml
log.md		log.md
pom.xml		pom.xml
run-client.bat		run-client.bat
run-client.sh		run-client.sh
run-server.bat		run-server.bat
run-server.sh		run-server.sh

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