HTTPService Printer

HTTPService Printer is a Node.js-based service that provides silent printing of HTML content to PDF and physical printers via a REST API. It uses Express, Puppeteer, and pdf-to-printer, and can be installed as a Windows service for always-on printing.

NPM

npm install -g invoice-print-service

Features

• Exposes HTTP endpoints for printing HTML to a physical printer.
• Automatically generates PDFs and sends them to the printer.
• Supports multiple printers and settings.
• Can run as a Windows service (install/uninstall script included).
• Uses Puppeteer for rendering HTML and Chrome for PDF generation.

Install the Service

The service.js script allows you to install/uninstall the Express print service as a Windows service.

1. Open a terminal in the project folder.
2. Install the service:

printserver install

• The service is named alen-print-service (or change the name in service.js).
• The service will start automatically.

3. To uninstall:

printserver uninstall

API Endpoints

GET /ping

Check if the service is online.

Response:

{
  "printerIsOnline": true
}

GET /printers

List available printers and the default printer.

Response Example:

[
  {
    "deviceId": "Printer1",
    "name": "HP LaserJet",
    "isDefault": true
  },
  {
    "deviceId": "Printer2",
    "name": "Canon Inkjet"
  }
]

POST /print

Print HTML content to a specified printer.

Request Body:

{
  "deviceId": "Printer1",
  "html": "<h1>Hello World</h1>",
  "settings": { "format": "A4" }
}

Response Example:

{
  "printer": { "deviceId": "Printer1", "name": "HP LaserJet" },
  "status": "printed"
}

How It Works

1. Receives HTML content via POST /print.
2. Generates a temporary PDF using Puppeteer and Chrome.
3. Sends the PDF to the selected printer using pdf-to-printer.
4. Deletes the temporary PDF after printing.
5. Supports queued printing via printQueue.js.

Logging

Logs are generated using logger.js. You can customize it to output to console, files, or external logging services.

Notes

• Chrome must be installed and detected by chrome-launcher.
• Temporary PDFs are stored in the jobs/ folder inside the project directory.
• The service is silent; no browser windows will open during printing (headless: true).