Dhalang Build Status

Dhalang is a Ruby wrapper for Google's Puppeteer.

Features

  • Generate PDFs from pages
  • Generate PDFs from html ( external images/stylesheets supported )
  • Capture a screenshot of a webpage

Installation

Add this line to your application's Gemfile:

gem 'Dhalang'

And then execute:

$ bundle update

Install puppeteer in your application's root directory:

$ npm install puppeteer

NodeJS v10.18.1 or greater is required

Usage

Get a 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.

Get a PDF of a HTML string
Dhalang::PDF.get_from_html("<html><head></head><body><h1>examplestring</h1></body></html>")

Get a PNG screenshot of a website
Dhalang::Screenshot.get_from_url_as_png("https://www.google.com")

Get a JPEG screenshot of a website
Dhalang::Screenshot.get_from_url_as_jpeg("https://www.google.com")

All methods return a string containing the PDF or JPEG/PNG in binary.

Custom PDF/screenshot 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_as_png("https://www.google.com", {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.md#pagepdfoptions

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

Custom user options

You may want to change the way Dhalang interacts with Puppeteer in general. User options can be set by providing them in a hash as last argument to any calls you make to the library. Are you setting both custom PDF and user options? Then they should be passed as a single hash.

For example to set a custom navigation timeout: Dhalang::Screenshot.get_from_url_as_jpeg("https://www.google.com", {navigationTimeout: 20000})

Below table lists all possible configuration parameters that can be set: | Key | Description | Default | |--------------------|-----------------------------------------------------------------------------------------|---------------------------------| | navigationTimeout | Amount of milliseconds until Puppeteer while timeout when navigating to the given page | 10000 | | 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 | | isHeadless | Indicates if Chromium should be launched headless | true | | 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 |

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 PNG from a Rails controller you can do the following: 

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

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

def example_controller_method  
    binary_jpeg = Dhalang::Screenshot.get_from_url_as_jpeg("https://www.google.com")
    send_data(binary_jpeg, filename: 'screenshotofgoogle.jpeg', type: 'image/jpeg')   
end