@cdl/ssr

CDL Server-Side Rendering and Export Service

Service for rendering CDL charts to PNG, SVG, or PDF on the server side using Puppeteer.

Installation

cd packages/ssr
npm install

Usage

Start the Server

npm start

Server will start on http://localhost:3000 by default.

API Endpoints

POST /api/export

Export a CDL chart to an image.

Request:

curl -X POST http://localhost:3000/api/export \
  -H "Content-Type: application/json" \
  -d '{
    "source": "@lang(data)\nSalesData { month,sales 1月,100 2月,150 }\nChart { use SalesData type line x month y sales }",
    "format": "png",
    "width": 800,
    "height": 600
  }' \
  --output chart.png

Parameters:

• source (string, required) - CDL source code
• format (string, optional) - Output format: png, svg, or pdf. Default: png
• width (number, optional) - Output width in pixels. Default: 800
• height (number, optional) - Output height in pixels. Default: 600
• backgroundColor (string, optional) - Background color. Default: #ffffff

Response:

• Success: Binary image data with appropriate Content-Type
• Error: JSON with error field

GET /health

Health check endpoint.

Response:

{
  "status": "ok",
  "timestamp": "2025-03-15T..."
}

Programmatic Usage

import axios from 'axios';

const response = await axios.post('http://localhost:3000/api/export', {
  source: cdlSource,
  format: 'png',
  width: 1024,
  height: 768
}, {
  responseType: 'stream'
});

response.data.pipe(fs.createWriteStream('chart.png'));

Docker

Build and run with Docker:

docker build -t cdl-ssr .
docker run -p 3000:3000 cdl-ssr

Configuration

Environment variables:

• PORT - Server port (default: 3000)
• PUPPETEER_EXECUTABLE_PATH - Path to Chrome/Chromium executable
• CDL_SSR_TIMEOUT - Render timeout in ms (default: 30000)

License

MIT