walterra/node-html2img-render-server repository overview

⁠node-html2img-render-server

HTML to image rendering service using Playwright's headless browser.

⁠Overview

A service for converting HTML to images with a REST API. It accepts direct HTML, CSS, and JavaScript input and returns screenshots for visual testing and image generation.

⁠Features

• Direct HTML/CSS/JS input without requiring public URLs
• Configurable viewport and wait conditions
• Element selection and clipping
• PNG/JPEG format support with quality settings
• Custom font and image injection
• API key authentication and rate limiting
• OpenTelemetry instrumentation with detailed tracing
• JSON or binary image response formats

⁠Quick Start

# Run with default settings
docker run -p 3000:3000 -e API_KEY=your-api-key walterra/node-html2img-render-server:latest

# Run with OpenTelemetry for observability
docker run -p 3000:3000 \
  -e API_KEY=your-api-key \
  -e OTEL_SERVICE_NAME=html-renderer \
  -e OTEL_EXPORTER_OTLP_ENDPOINT=https://your-apm-endpoint:443 \
  -e OTEL_EXPORTER_OTLP_HEADERS="Authorization=ApiKey your-api-key" \
  walterra/node-html2img-render-server:latest

⁠Usage Example

curl -X POST \
  -H "Content-Type: application/json" \
  -H "X-API-Key: your-api-key" \
  -d '{
    "html": "<div style=\"width:100px;height:100px;background-color:blue;\"></div>",
    "viewport": {"width": 500, "height": 400},
    "format": "png"
  }' \
  http://localhost:3000/render > screenshot.png

⁠Environment Variables

⁠Required

• API_KEY: Authentication key for API access

⁠Optional

• PORT: Server port (default: 3000)
• NODE_ENV: Environment (development, production)
• RATE_LIMIT_MAX: Maximum requests per window (default: 60)
• RATE_LIMIT_WINDOW_MS: Rate limit window in ms (default: 60000)
• REQUEST_TIMEOUT_MS: Request timeout in ms (default: 30000)

⁠OpenTelemetry Settings

• OTEL_SERVICE_NAME: Service name for telemetry
• OTEL_EXPORTER_OTLP_ENDPOINT: OpenTelemetry collector endpoint
• OTEL_EXPORTER_OTLP_HEADERS: Headers for endpoint authentication
• OTEL_SDK_DISABLED: Set to true to disable telemetry

⁠API Parameters

{
  "html": "<div>Content to render</div>",
  "css": "div { color: blue; }",
  "javascript": "document.querySelector('div').textContent = 'Dynamic content';",
  "viewport": {
    "width": 1280,
    "height": 720,
    "deviceScaleFactor": 1
  },
  "waitForSelector": "#ready-element",
  "clipSelector": "#capture-this",
  "format": "png",
  "quality": 90,
  "responseFormat": "image"
}

⁠Links

• GitHub Repository⁠
• Documentation⁠
• Examples⁠
• Release Notes⁠

⁠Supported Tags

• latest: Latest stable release
• 1.1.1: Enhanced OpenTelemetry instrumentation
• 1.1.0: Initial OpenTelemetry support
• 1.0.1: Maintenance release with Docker improvements
• 1.0.0: Initial version

⁠License

MIT