Chromiumly

A lightweight Typescript library that interacts with Gotenberg's different modules to convert a variety of document formats to PDF files.

Install

Using npm:

npm install chromiumly

Using yarn:

yarn add chromiumly

Prerequisites

Before attempting to use Chromiumly, be sure you install Docker if you have not already done so.

After that, you can start a default Docker container of Gotenberg as follows:

docker run --rm -p 3000:3000 gotenberg/gotenberg:7

Get Started

Configuration

Chromiumly supports both dotenv and config configuration libraries to add Gotenberg endpoint to your project.

dotenv

GOTENBERG_ENDPOINT=http://localhost:3000

config

{
  "gotenberg": {
    "endpoint": "http://localhost:3000"
  }
}

Modules

Chromiumly introduces different classes that serve as wrappers to Gotenberg's modules.

Chormium

There are three different classes that come with a single method (i.e.convert) which calls one of Chromium's routes to convert html and markdown files, or a url to a buffer which contains the converted PDF file content.

URL

import { UrlConverter } from "chromiumly";

const urlConverter = new UrlConverter();
const buffer = await urlConverter.convert({
    url: "https://www.example.com/",
});

HTML

The only requirement is that the file name should be index.html.

import { HtmlConverter } from "chromiumly";

const htmlConverter = new HtmlConverter();
const buffer = await htmlConverter.convert({
    html: "path/to/index.html",
});

Markdown

This route accepts an index.html file plus a markdown file.

import { MarkdownConverter } from "chromiumly";

const markdownConverter = new MarkdownConverter();
const buffer = await markdownConverter.convert({
    html: "path/to/index.html",
    markdown: "path/to/file.md",
});

Customization

convert() method takes an optional properties parameter of the following type which dictates how the PDF generated file will look like.

type PageProperties = {
  size?: {
    width: number; // Paper width, in inches (default 8.5)
    height: number; //Paper height, in inches (default 11)
  };
  margins?: {
    top: number; // Top margin, in inches (default 0.39)
    bottom: number; // Bottom margin, in inches (default 0.39)
    left: number; // Left margin, in inches (default 0.39)
    right: number; // Right margin, in inches (default 0.39)
  };
  preferCssPageSize?: boolean; // Define whether to prefer page size as defined by CSS (default false)
  printBackground?: boolean; // Print the background graphics (default false)
  landscape?: boolean; // Set the paper orientation to landscape (default false)
  scale?: number; // The scale of the page rendering (default 1.0)
  nativePageRanges?: { from: number; to: number }; // Page ranges to print
};

PDF Engine

The PDFEngine combines the functionality of both Gotenberg's PDF Engines and LibreOffice modules to manipulate different file formats.

convert

This method interacts with LibreOffice module to convert different documents to PDF files. You can find the file extensions accepted here.

import { PDFEngine } from "chromiumly";

const buffer = await PDFEngine.convert({
  files: ["path/to/file.docx", "path/to/file.png"],
});

Similarly to Chromium's module convert method, this method takes the following optional parameters :

• properties: changes how the PDF generated file will look like.
• pdfFormat: PDF format of the conversion resulting file (i.e. PDF/A-1a, PDF/A-2b, PDF/A-3b).
• merge: merge all the resulting files from the conversion into an individual PDF file.

merge

This method interacts with PDF Engines module which gathers different engines that can manipulate and merge PDF files such as: PDFtk, PDFcpu, QPDF, and UNO.

import { PDFEngine } from "chromiumly";

const buffer = await PDFEngine.merge({
  files: ["path/to/file.docx", "path/to/file.png"],
});

generate

It is just a generic complementary method that takes the buffer returned by the convert method, and a chosen filename to generate the PDF file.

Please note that all the PDF files can be found __generated__ folder in the root folder of your project.

Snippet

The following is a short snippet of how to use the library.

import { PDFEngine, UrlConverter } from "chromiumly";

async function run() {
  const urlConverter = new UrlConverter();
  const buffer = await urlConverter.convert({
    url: "https://gotenberg.dev/",
  });

  await PDFEngine.generate("gotenberg.pdf", buffer);
}

run();