City Digital Twin — Backend & Frontend Setup Guide

This guide explains how to set up and run the backend and frontend services for the City Digital Twin project in a local development environment.

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Prerequisites

Make sure you have the following installed:

• Node.js (v16 or higher recommended)
• npm (Node Package Manager)
• Git

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Directory Structure

city-digital-twin/
├── backend/
│   ├── .env
│   └── (source code)
└── frontend/
    ├── .env
    └── (source code)

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Environment Variables (.env)

Before running the project, you need to create .env files for both backend and frontend.

Backend .env example:

Create backend/.env:

ENDPOINT_URL=http://your-graphdb-endpoint-url

Replace http://your-graphdb-endpoint-url with your actual GraphDB endpoint.

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Frontend .env example:

Create frontend/.env:

REACT_APP_API_URL=http://localhost:3000

This tells the frontend where to send API requests. (It should points to the backend address)

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Running Backend and Frontend Locally

You can use the provided script to automatically install dependencies and start both services.

Using a Script

On Windows: Run the run_windowns.bat script.

On Mac: Run the run_shell script.

To Run Manually:

Step to run backend (run backend first)

cd backend/

npm install

npx nodemon index.js &

Step to run frontend

cd frontend

npm install

npm run dev-start

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Expected Behavior

• The backend server (API) will start on port 3000.
• The frontend React development server will start on port 3001 or 3000 (depending on configuration).
• When you stop the frontend (CTRL+C), the backend server will also be stopped automatically.

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Notes

• Make sure to update the .env files with your actual API endpoints.
• This script is intended for development only — for production use Docker-based deployment.
• If you modify the backend code, nodemon will auto-restart the server.