🚀 QBar

QBar is a lightweight Spring Boot service for generating QR codes and barcodes.
It supports Redis caching to improve performance for repeated requests.
The service exposes a REST API that returns PNG images.

✨ Features

• Generate QR codes and all ZXing-supported barcode formats (CODE 128, EAN, UPC, etc.)
• Configurable width and height
• Redis caching to speed up repeated requests
• Ready to run in Docker
• Configurable via Spring profiles (application.properties and application-docker.properties)
• Uses ImageUtils for optimized image-to-byte conversion

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🛠️ Technologies Used

• Java 21
• Spring Boot 3.5
• Spring Cache + Redis
• ZXing (QR and barcode generation)
• Docker / Docker Compose

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🏁 Getting Started

Prerequisites

• Docker & Docker Compose
• Java 21 (optional if running outside Docker)
• Maven (optional if running outside Docker)

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🐳 Run with Docker

# Build and start services
docker-compose up --build

• QBar service will be available at: http://localhost:8081
• Redis is available internally at redis:6379

📬 API Endpoint

Generate QR / Barcode

POST /api/codes/generate

Content-Type: application/json
Accept: image/png

📝 Request JSON

{
  "text": "HelloWorld",
  "type": "QR",
  "width": 300,
  "height": 300
}

• text ✏️: The data you want to encode.
• type 🔢: Barcode type (QR, CODE_128, EAN_13, UPC_A, etc.)
• width 📏: Width of the image in pixels.
• height 📐: Height of the image in pixels.

🖼️ Response

Content-Type: image/png
Body: PNG image of the generated QR code or barcode.

Example with cURL:

curl -X POST http://localhost:8081/api/codes/generate \
     -H "Content-Type: application/json" \
     -H "Accept: image/png" \
     -d '{"text":"HelloWorld","type":"QR","width":300,"height":300}' \
     --output qr.png

The generated QR code image will be saved as qr.png ✅

🔢 Example for Code 128 Barcode

{
  "text": "1234567890",
  "type": "CODE_128",
  "width": 400,
  "height": 150
}

Saves the generated barcode as barcode.png using the same cURL command with updated JSON.

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🛣️ Roadmap

• Support additional barcode formats (e.g., EAN, UPC)
• Add custom colors and logo overlays for QR codes 🎨
• Implement rate limiting to avoid abuse 🚦
• Add API key authentication for secure access 🔑
• Provide online frontend for quick QR/barcode generation 🌐
• Enable dynamic TTL for cached codes ⏳
• Add unit & integration tests for all endpoints ✅