pdfkit

A Ruby gem to transform HTML + CSS into PDFs using the command-line utility wkhtmltopdf

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Ruby

PDFKit

Create PDFs using plain old HTML+CSS. Uses wkhtmltopdf on the back-end which renders HTML using Webkit.

Supported versions

  • Ruby 2.5, 2.6, 2.7, 3.0, 3.1
  • Rails 4.2, 5.2, 6.0, 6.1, 7.0

Install

PDFKit

gem install pdfkit

wkhtmltopdf

  1. Install by hand (recommended):

    https://github.com/pdfkit/pdfkit/wiki/Installing-WKHTMLTOPDF

  2. Try using the wkhtmltopdf-binary-edge gem (mac + linux i386)

gem install wkhtmltopdf-binary

Note: The automated installer has been removed.

Usage

# PDFKit.new takes the HTML and any options for wkhtmltopdf
# run `wkhtmltopdf --extended-help` for a full list of options
kit = PDFKit.new(html, :page_size => 'Letter')
kit.stylesheets << '/path/to/css/file'

# Get an inline PDF
pdf = kit.to_pdf

# Save the PDF to a file
file = kit.to_file('/path/to/save/pdf')

# PDFKit.new can optionally accept a URL or a File.
# Stylesheets can not be added when source is provided as a URL or File.
kit = PDFKit.new('http://google.com')
kit = PDFKit.new(File.new('/path/to/html'))

# Add any kind of option through meta tags
PDFKit.new('<html><head><meta name="pdfkit-page_size" content="Letter"')
PDFKit.new('<html><head><meta name="pdfkit-cookie cookie_name1" content="cookie_value1"')
PDFKit.new('<html><head><meta name="pdfkit-cookie cookie_name2" content="cookie_value2"')

Resolving relative URLs and protocols

If the source HTML has relative URLs (/images/cat.png) or
protocols
(//example.com/site.css) that need to be resolved, you can pass :root_url
and :protocol options to PDFKit:

PDFKit.new(html, root_url: 'http://mysite.com/').to_file
# or:
PDFKit.new(html, protocol: 'https').to_file

Using cookies in scraping

If you want to pass a cookie to pdfkit to scrape a website, you can
pass it in a hash:

kit = PDFKit.new(url, cookie: {cookie_name: :cookie_value})
kit = PDFKit.new(url, [:cookie, :cookie_name1] => :cookie_val1, [:cookie, :cookie_name2] => :cookie_val2)

Configuration

If you’re on Windows or you would like to use a specific wkhtmltopdf you installed, you will need to tell PDFKit where the binary is. PDFKit will try to intelligently guess at the location of wkhtmltopdf by running the command which wkhtmltopdf. If you are on Windows, want to point PDFKit to a different binary, or are having trouble with getting PDFKit to find your binary, please manually configure the wkhtmltopdf location. You can configure PDFKit like so:

# config/initializers/pdfkit.rb
PDFKit.configure do |config|
  config.wkhtmltopdf = '/path/to/wkhtmltopdf'
  config.default_options = {
    :page_size => 'Legal',
    :print_media_type => true
  }
  # Use only if your external hostname is unavailable on the server.
  config.root_url = "http://localhost"
  config.verbose = false
end

Middleware

PDFKit comes with a middleware that allows users to get a PDF view of any page on your site by appending .pdf to the URL.

Middleware Setup

Non-Rails Rack apps

# in config.ru
require 'pdfkit'
use PDFKit::Middleware

Rails apps

# in application.rb(Rails3) or environment.rb(Rails2)
require 'pdfkit'
config.middleware.use PDFKit::Middleware

With PDFKit options

# options will be passed to PDFKit.new
config.middleware.use PDFKit::Middleware, :print_media_type => true

With conditions to limit routes that can be generated in pdf

# conditions can be regexps (either one or an array)
config.middleware.use PDFKit::Middleware, {}, :only => %r[^/public]
config.middleware.use PDFKit::Middleware, {}, :only => [%r[^/invoice], %r[^/public]]

# conditions can be strings (either one or an array)
config.middleware.use PDFKit::Middleware, {}, :only => '/public'
config.middleware.use PDFKit::Middleware, {}, :only => ['/invoice', '/public']

# conditions can be regexps (either one or an array)
config.middleware.use PDFKit::Middleware, {}, :except => [%r[^/prawn], %r[^/secret]]

# conditions can be strings (either one or an array)
config.middleware.use PDFKit::Middleware, {}, :except => ['/secret']

With conditions to force download

# force download with attachment disposition
config.middleware.use PDFKit::Middleware, {}, :disposition => 'attachment'
# conditions can force a filename
config.middleware.use PDFKit::Middleware, {}, :disposition => 'attachment; filename=report.pdf'

Saving the generated .pdf to disk

Setting the PDFKit-save-pdf header will cause PDFKit to write the generated .pdf to the file indicated by the value of the header.

For example:

headers['PDFKit-save-pdf'] = 'path/to/saved.pdf'

Will cause the .pdf to be saved to path/to/saved.pdf in addition to being sent back to the client. If the path is not writable/non-existent the write will fail silently. The PDFKit-save-pdf header is never sent back to the client.

Troubleshooting

  • Single thread issue: In development environments it is common to run a
    single server process. This can cause issues when rendering your pdf
    requires wkhtmltopdf to hit your server again (for images, js, css).
    This is because the resource requests will get blocked by the initial
    request and the initial request will be waiting on the resource
    requests causing a deadlock.

    This is usually not an issue in a production environment. To get
    around this issue you may want to run a server with multiple workers
    like Passenger or try to embed your resources within your HTML to
    avoid extra HTTP requests.

    Example solution (rails / bundler), add unicorn to the development
    group in your Gemfile gem 'unicorn' then run bundle. Next, add a
    file config/unicorn.conf with

     worker_processes 3
    

    Then to run the app unicorn_rails -c config/unicorn.conf (from rails_root)

  • Resources aren’t included in the PDF: Images, CSS, or JavaScript
    does not seem to be downloading correctly in the PDF. This is due
    to the fact that wkhtmltopdf does not know where to find those files.
    Make sure you are using absolute paths (start with forward slash) to
    your resources. If you are using PDFKit to generate PDFs from a raw
    HTML source make sure you use complete paths (either file paths or
    urls including the domain). In restrictive server environments the
    root_url configuration may be what you are looking for change your
    asset host.

  • Mangled output in the browser: Be sure that your HTTP response
    headers specify “content-type: application/pdf”

Note on Patches/Pull Requests

  • Fork the project.
  • Setup your development environment with: gem install bundler; bundle install
  • Make your feature addition or bug fix.
  • Add tests for it. This is important so I don’t break it in a
    future version unintentionally.
  • Commit, do not mess with rakefile, version, or history.
    (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
  • Send me a pull request. Bonus points for topic branches.

Copyright

Copyright © 2010 Jared Pace. See LICENSE for details.