Project

Dhalang

0.04
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A long-lived project that still receives updates
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Ruby wrapper for Puppeteer. Generate screenshots and PDF's from HTML!
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 Popularity
Downloads
70,986
Stars
40
Forks
23
Watchers
2
 Releases
Current version
0.7.2
Total releases
16
First release
2019-02-07
Latest release
2024-12-16
 Issues
Open Issues
3
Closed Issues
8
Total Issues
11
Issue Closure Rate
72%
 Pull Requests
Open Pull Requests
0
Closed Pull Requests
1
Merged Pull Requests
60
Pull Request Acceptance Rate
98%
 Development
Primary Language
Ruby
Licenses
MIT
Average date of last 50 commits
2024-01-12
Reverse Dependencies
0

 Dependencies

Development

rspec
~> 3.0
bundler
~> 2.3.6
fastimage
~> 2.2.6
pdf-reader
~> 2.9.0
rake
~> 13.0.6
 Project Readme

Dhalang Build Gem Version

Dhalang is a Ruby wrapper for Google's Puppeteer.

Features

  • Generate PDFs from webpages
  • Generate PDFs from HTML ( external images/stylesheets supported )
  • Capture screenshots from webpages
  • Scrape HTML from webpages

Prerequisites

  • Node ≥ 18
  • Puppeteer ≥ 22
  • Unix shell ( Dhalang will not work on Windows shells )

Installation

Add this line to your application's Gemfile:

gem 'Dhalang'

And then execute:

$ bundle update

Install puppeteer or puppeteer-core in your application's root directory:

$ npm install puppeteer 
or
$ npm install puppeteer-core

Usage

PDF of a website url

Dhalang::PDF.get_from_url("https://www.google.com")

It is important to pass the complete url, leaving out https://, http:// or www. will result in an error.

PDF of a HTML string

Dhalang::PDF.get_from_html("<html><head></head><body><h1>examplestring</h1></body></html>")

PNG screenshot of a website

Dhalang::Screenshot.get_from_url("https://www.google.com", :png)

JPEG screenshot of a website

Dhalang::Screenshot.get_from_url("https://www.google.com", :jpeg)

WEBP screenshot of a website

Dhalang::Screenshot.get_from_url("https://www.google.com", :webp)

HTML of a website

Dhalang::Scraper.html("https://www.google.com")

Above methods either return a string containing the PDF/JPEG/PNG/WEBP in binary or the scraped HTML.

Custom options

To override the default options that are set by Dhalang you can pass as last argument a hash with the custom options you want to set.

For example to set custom margins for PDFs:

Dhalang::PDF.get_from_url("https://www.google.com", {margin: { top: 100, right: 100, bottom: 100, left: 100}})

For example to only take a screenshot of the visible part of the page:

Dhalang::Screenshot.get_from_url("https://www.google.com", :webp, {fullPage: false})

A list of all possible PDF options that can be set, can be found at: https://github.com/puppeteer/puppeteer/blob/main/docs/api/puppeteer.pdfoptions.md

A list of all possible screenshot options that can be set, can be found at: https://github.com/puppeteer/puppeteer/blob/main/docs/api/puppeteer.screenshotoptions.md

The default Puppeteer options contain the options headerTemplate and footerTemplate. Puppeteer expects these to be HTML strings. By default, the Dhalang gem passes all options as arguments in a node ... shell command. In case the HTML strings are too long they might surpass the maximum argument length of the host. For example, on Linux the MAX_ARG_LEN is 128kB. Therefore, you can also pass the headers and footers as file path using the options headerTemplateFile and footerTemplateFile. These non-Puppeteer-options will be used to populate the Puppeteer-options headerTemplate and footerTemplate.

For example: Dhalang::PDF.get_from_url("https://www.google.com", {headerTemplateFile: '/tmp/header.html', footerTemplateFile: '/tmp/footer.html'})

Below table lists more configuration parameters that can be set:

Key Description Default
isHeadless Indicates if Chromium should be launched headless (useful for debugging) true
slowMo Amount of milliseconds to slow down Puppeteer operations (useful for debugging) 0
browserWebsocketUrl Websocket url of remote chromium browser to use None
navigationTimeout Amount of milliseconds until Puppeteer while timeout when navigating to the given page 10000
printToPDFTimeout Amount of milliseconds until Puppeteer while timeout when calling Page.printToPDF 0 (unlimited)
navigationWaitForSelector If set, Dhalang will wait for the specified selector to appear before creating the screenshot or PDF None
navigationWaitForXPath If set, Dhalang will wait for the specified XPath to appear before creating the screenshot or PDF None
userAgent User agent to send with the request Default Puppeteer one
isAutoHeight When set to true the height of generated PDFs will be based on the scrollHeight property of the document body false
viewPort Custom viewport to use for the request Default Puppeteer one
httpAuthenticationCredentials Custom HTTP authentication credentials to use for the request None
chromeOptions A array of options that can be passed to puppeteer in addition to the mandatory ['--no-sandbox', '--disable-setuid-sandbox'] []

Examples of using Dhalang

To return a PDF from a Rails controller you can do the following:

def example_controller_method
  binary_pdf = Dhalang::PDF.get_from_url("https://www.google.com")  
  send_data(binary_pdf, filename: 'pdfofgoogle.pdf', type: 'application/pdf')  
end

To return a screenshot from a Rails controller you can do the following:

def example_controller_method
  binary_png = Dhalang::Screenshot.get_from_url("https://www.google.com", :png)
  send_data(binary_png, filename: 'screenshotofgoogle.png', type: 'image/png')   
end