cherfia
A lightweight Typescript library that interacts with Gotenberg's different routes to convert a variety of document formats to PDF files.
Table of Contents
Getting Started
Installation
Using npm:
npm install chromiumlyUsing yarn:
yarn add chromiumlyPrerequisites
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:8Configuration
Chromiumly supports configurations via both dotenv and config configuration libraries or directly via code to add Gotenberg endpoint to your project.
dotenv
GOTENBERG_ENDPOINT=http://localhost:3000config
{
"gotenberg": {
"endpoint": "http://localhost:3000"
}
}code
import { Chromiumly } from "chromiumly";
Chromiumly.configure({ endpoint: "http://localhost:3000" });Authentication
Basic Authentication
Gotenberg introduces basic authentication support starting from version 8.4.0. Suppose you are running a Docker container using the command below:
docker run --rm -p 3000:3000 \
-e GOTENBERG_API_BASIC_AUTH_USERNAME=user \
-e GOTENBERG_API_BASIC_AUTH_PASSWORD=pass \
gotenberg/gotenberg:8.4.0 gotenberg --api-enable-basic-authTo integrate this setup with Chromiumly, you need to update your configuration as outlined below:
GOTENBERG_ENDPOINT=http://localhost:3000
GOTENBERG_API_BASIC_AUTH_USERNAME=user
GOTENBERG_API_BASIC_AUTH_PASSWORD=passOr
{
"gotenberg": {
"endpoint": "http://localhost:3000",
"api": {
"basicAuth": {
"username": "user",
"password": "pass"
}
}
}
}Or
Chromiumly.configure({
endpoint: "http://localhost:3000",
username: "user",
password: "pass",
});Advanced Authentication
To implement advanced authentication or add custom HTTP headers to your requests, you can use the customHttpHeaders option within the configure method. This allows you to pass additional headers, such as authentication tokens or custom metadata, with each API call.
For example, you can include a Bearer token for authentication along with a custom header as follows:
const token = await generateToken();
Chromiumly.configure({
endpoint: "http://localhost:3000",
customHttpHeaders: {
Authorization: `Bearer ${token}`,
"X-Custom-Header": "value",
},
});Core Features
Chromiumly introduces different classes that serve as wrappers to
Gotenberg's routes. These classes encompass methods featuring an
input file parameter, such as html, header, footer, and markdown, capable of accepting inputs in the form of a
string (i.e. file path), Buffer, or ReadStream.
Chromium
There are three different classes that come with a single method (i.e.convert) which calls one of
Chromium's Conversion routes to convert html and markdown files, or
a url to a buffer which contains the converted PDF file content.
Similarly, a new set of classes have been added to harness the recently introduced Gotenberg Screenshot routes. These classes include a single method called capture, which allows capturing full-page screenshots of html, markdown, and url.
URL
import { UrlConverter } from "chromiumly";
const urlConverter = new UrlConverter();
const buffer = await urlConverter.convert({
url: "https://www.example.com/",
});import { UrlScreenshot } from "chromiumly";
const screenshot = new UrlScreenshot();
const buffer = await screenshot.capture({
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",
});import { HtmlScreenshot } from "chromiumly";
const screenshot = new HtmlScreenshot();
const buffer = await screenshot.capture({
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",
});import { MarkdownScreenshot } from "chromiumly";
const screenshot = new MarkdownScreenshot();
const buffer = await screenshot.capture({
html: "path/to/index.html",
markdown: "path/to/file.md",
});Each convert() method takes an optional properties parameter of the following type which dictates how the PDF generated
file will look like.
type PageProperties = {
singlePage?: boolean; // Print the entire content in one single page (default false)
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)
omitBackground?: boolean; // Hide the default white background and allow generating PDFs with transparency (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
};In addition to the PageProperties customization options, the convert() method also accepts a set of parameters to further enhance the versatility of the conversion process. Here's an overview of the full list of parameters:
type ConversionOptions = {
properties?: PageProperties; // Customize the appearance of the generated PDF
pdfFormat?: PdfFormat; // Define the PDF format for the conversion
pdfUA?: boolean; // Enable PDF for Universal Access for optimal accessibility (default false)
userAgent?: string; // Customize the user agent string sent during conversion
header?: PathLikeOrReadStream; // Specify a custom header for the PDF
footer?: PathLikeOrReadStream; // Specify a custom footer for the PDF
emulatedMediaType?: EmulatedMediaType; // Specify the emulated media type for conversion
waitDelay?: string; // Duration (e.g., '5s') to wait when loading an HTML document before conversion
waitForExpression?: string; // JavaScript expression to wait before converting an HTML document into PDF
extraHttpHeaders?: Record<string, string>; // Include additional HTTP headers in the request
failOnHttpStatusCodes?: number[]; // List of HTTP status codes triggering a 409 Conflict response (default [499, 599])
failOnConsoleExceptions?: boolean; // Return a 409 Conflict response if there are exceptions in the Chromium console (default false)
skipNetworkIdleEvent?: boolean; // Do not wait for Chromium network to be idle (default true)
metadata?: Metadata; // Metadata to be written.
cookies?: Cookie[]; // Cookies to be written.
downloadFrom?: DownloadFrom; //Download a file from a URL. It must return a Content-Disposition header with a filename parameter.
split?: SplitOptions; // Split the PDF file into multiple files.
};Screenshot
Similarly, the capture() method takes an optional properties parameter of the specified type, influencing the appearance of the captured screenshot file.
type ImageProperties = {
format: "png" | "jpeg" | "webp"; //The image compression format, either "png", "jpeg" or "webp".
quality?: number; // The compression quality from range 0 to 100 (jpeg only).
omitBackground?: boolean; // Hide the default white background and allow generating screenshots with transparency.
width?: number; // The device screen width in pixels (default 800).
height?: number; // The device screen height in pixels (default 600).
clip?: boolean; // Define whether to clip the screenshot according to the device dimensions (default false).
};Furthermore, alongside the customization options offered by ImageProperties, the capture() method accommodates a variety of parameters to expand the versatility of the screenshot process. Below is a comprehensive overview of all parameters available:
type ScreenshotOptions = {
properties?: ImageProperties;
header?: PathLikeOrReadStream;
footer?: PathLikeOrReadStream;
emulatedMediaType?: EmulatedMediaType;
waitDelay?: string; // Duration (e.g, '5s') to wait when loading an HTML document before convertion.
waitForExpression?: string; // JavaScript's expression to wait before converting an HTML document into PDF until it returns true.
extraHttpHeaders?: Record<string, string>;
failOnHttpStatusCodes?: number[]; // Return a 409 Conflict response if the HTTP status code is in the list (default [499,599])
failOnConsoleExceptions?: boolean; // Return a 409 Conflict response if there are exceptions in the Chromium console (default false)
skipNetworkIdleEvent?: boolean; // Do not wait for Chromium network to be idle (default true)
optimizeForSpeed?: boolean; // Define whether to optimize image encoding for speed, not for resulting size.
cookies?: Cookie[]; // Cookies to be written.
downloadFrom?: DownloadFrom; // Download the file from a specific URL. It must return a Content-Disposition header with a filename parameter.
};LibreOffice
The LibreOffice class comes with a single method convert. This method interacts with LibreOffice route to convert different documents to PDF files. You can find the file extensions
accepted here.
import { LibreOffice } from "chromiumly";
const buffer = await LibreOffice.convert({
files: [
"path/to/file.docx",
"path/to/file.png",
{ data: xlsxFileBuffer, ext: "xlsx" },
],
});Similarly to Chromium's route convert method, this method takes the following optional parameters :
properties: changes how the PDF generated file will look like. It also includes apasswordparameter to open the source file.pdfa: PDF format of the conversion resulting file (i.e.PDF/A-1a,PDF/A-2b,PDF/A-3b).pdfUA: enables PDF for Universal Access for optimal accessibility.merge: merges all the resulting files from the conversion into an individual PDF file.metadata: writes metadata to the generated PDF file.lolosslessImageCompression: allows turning lossless compression on or off to tweak image conversion performance.reduceImageResolution: allows turning on or off image resolution reduction to tweak image conversion performance.quality: specifies the quality of the JPG export. The value ranges from 1 to 100, with higher values producing higher-quality images and larger file sizes.maxImageResolution: specifies if all images will be reduced to the specified DPI value. Possible values are:75,150,300,600, and1200.flatten: a boolean that, when set to true, flattens the split PDF files, making form fields and annotations uneditable.
PDF Engines
The PDFEngines class interacts with Gotenberg's PDF Engines routes to manipulate PDF files.
Format Conversion
This method interacts with PDF Engines convertion route to transform PDF files into the requested PDF/A format and/or PDF/UA.
import { PDFEngines } from "chromiumly";
const buffer = await PDFEngines.convert({
files: ["path/to/file_1.pdf", "path/to/file_2.pdf"],
pdfa: PdfFormat.A_2b,
pdfUA: true,
});Merging
This method interacts with PDF Engines merge route which gathers different engines that can manipulate and merge PDF files such as: PDFtk, PDFcpu, QPDF, and UNO.
import { PDFEngines } from "chromiumly";
const buffer = await PDFEngines.merge({
files: ["path/to/file_1.pdf", "path/to/file_2.pdf"],
pdfa: PdfFormat.A_2b,
pdfUA: true,
});Metadata Management
readMetadata
This method reads metadata from the provided PDF files.
import { PDFEngines } from "chromiumly";
const metadataBuffer = await PDFEngines.readMetadata([
"path/to/file_1.pdf",
"path/to/file_2.pdf",
]);writeMetadata
This method writes metadata to the provided PDF files.
import { PDFEngines } from "chromiumly";
const buffer = await PDFEngines.writeMetadata({
files: [
"path/to/file_1.pdf",
"path/to/file_2.pdf",
],
metadata: {
Author: 'Taha Cherfia',
Tite: 'Chromiumly'
Keywords: ['pdf', 'html', 'gotenberg'],
}
});Please consider referring to ExifTool for a comprehensive list of accessible metadata options.
File Generation
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.
PDF Splitting
Each Chromium and LibreOffice route has a split parameter that allows splitting the PDF file into multiple files. The split parameter is an object with the following properties:
mode: the mode of the split. It can bepagesorintervals.span: the span of the split. It is a string that represents the range of pages to split.unify: a boolean that allows unifying the split files. Only works whenmodeispages.flatten: a boolean that, when set to true, flattens the split PDF files, making form fields and annotations uneditable.
import { UrlConverter } from "chromiumly";
const buffer = await UrlConverter.convert({
url: "https://www.example.com/",
split: {
mode: "pages",
span: "1-2",
unify: true,
},
});On the other hand, PDFEngines' has a split method that interacts with PDF Engines split route which splits PDF files into multiple files.
import { PDFEngines } from "chromiumly";
const buffer = await PDFEngines.split({
files: ["path/to/file_1.pdf", "path/to/file_2.pdf"],
options: {
mode: "pages",
span: "1-2",
unify: true,
},
});⚠️ Note: Gotenberg does not currently validate the
spanvalue whenmodeis set topages, as the validation depends on the chosen engine for the split feature. See PDF Engines module configuration for more details.
PDF Flattening
PDF flattening converts interactive elements like forms and annotations into a static PDF. This ensures the document looks the same everywhere and prevents further edits.
import { PDFEngines } from "chromiumly";
const buffer = await PDFEngines.flatten({
files: ["path/to/file_1.pdf", "path/to/file_2.pdf"],
});Snippet
The following is a short snippet of how to use the library.
import { PDFEngines, UrlConverter } from "chromiumly";
async function run() {
const urlConverter = new UrlConverter();
const buffer = await urlConverter.convert({
url: "https://gotenberg.dev/",
properties: {
singlePage: true,
size: {
width: 8.5,
height: 11,
},
},
emulatedMediaType: "screen",
failOnHttpStatusCodes: [404],
failOnConsoleExceptions: true,
skipNetworkIdleEvent: false,
optimizeForSpeed: true,
split: {
mode: "pages",
span: "1-2",
unify: true,
},
});
await PDFEngines.generate("gotenberg.pdf", buffer);
}
run();