Note Search Engine

A modern note search application with hybrid search capabilities, combining local document management with web search integration.

✨ Features

• Hybrid Search: Combines BM25 and embedding-based search for accurate results
• Multi-format Support: Upload TXT, MD, PDF, and DOCX files
• Google Search Integration: Search the web alongside your local notes
• Tag-based Organization: Organize documents with tags and filter by tag
• User Authentication: Google, GitHub, Email/Password, and Guest mode via Firebase
• Multi-language UI: Supports English, Chinese, Japanese, Korean, Spanish, French, and German
• Customizable Themes: Multiple color themes with light/dark mode

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🎬 Demo

Authentication

Flexible sign-in options including Google, GitHub, Email/Password, or continue as a guest.

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Hybrid Search

Split-view interface showing Google search results on the left and local documents on the right.

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Home Page

Clean interface with Google search integration and local document library.

Dark Mode	Light Mode

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Document Management

Create new documents or upload existing files with custom tags.

Create Document	Upload Document

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Account Management

Guest users can link their account later to save documents permanently.

Guest User	Signed In

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Settings

Customize appearance, color themes, and language preferences.

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🛠 Tech Stack

Frontend

• React 18 + Vite
• React Router for navigation
• Firebase Authentication
• CSS Variables for theming

Backend

• Node.js + Express
• MongoDB with Mongoose
• Custom tokenizer for mixed-language text
• BM25 search algorithm

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🚀 Quick Start

Prerequisites

• Node.js 18+
• MongoDB (local or Atlas)

Installation

# Clone the repository
git clone https://github.com/Lou-Meixuan/Note_Search_Engine.git
cd Note_Search_Engine

# Install backend dependencies
cd backend
npm install

# Install frontend dependencies
cd ../frontend
npm install

Configuration

1. Backend: Create backend/.env:

MONGODB_URI=your_mongodb_connection_string
GOOGLE_API_KEY=your_google_api_key (optional)
GOOGLE_CX=your_google_search_cx (optional)

2. Frontend: Create frontend/.env:

VITE_API_URL=http://localhost:3001

Running Locally

# Terminal 1: Start backend
cd backend
npm start

# Terminal 2: Start frontend
cd frontend
npm run dev

Open http://localhost:5173 in your browser.

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📁 Project Structure

Note_Search_Engine/
├── frontend/               # React frontend
│   ├── src/
│   │   ├── components/     # Reusable UI components
│   │   ├── context/        # React contexts (Auth, Theme, Language)
│   │   ├── pages/          # Page components
│   │   ├── i18n/           # Translations
│   │   └── config/         # API configuration
│   └── ...
├── backend/                # Node.js backend
│   ├── src/
│   │   ├── app/            # Express routes and server
│   │   ├── data_access/    # Database and external services
│   │   ├── entity/         # Domain entities
│   │   ├── interface_adapter/  # Controllers and repositories
│   │   └── use_case/       # Business logic
│   └── docs/               # Architecture documentation
└── README.md

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🌐 Deployment

Backend (Render)

1. Create a Web Service on render.com
2. Set root directory to backend
3. Add environment variables (MONGODB_URI, etc.)

Frontend (Vercel)

1. Import project on vercel.com
2. Set root directory to frontend
3. Add VITE_API_URL pointing to your backend URL

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📄 License

MIT License - see LICENSE for details.