ChromicPDF is a HTML-to-PDF renderer for Elixir, based on headless Chrome.
- Node-free: In contrast to many other packages, it does not use puppeteer, and hence does not require Node.js. It communicates directly with Chrome's DevTools API over pipes, offering the same performance as puppeteer, if not better.
- Header/Footer: Using the DevTools API allows to apply the full set of options of the
printToPDF
function. Most notably, it supports header and footer HTML templates. - PDF/A: It can convert printed files to PDF/A using Ghostscript. Converted files pass the verapdf validator.
- Chromium or Chrome
- Ghostscript (optional, for PDF/A support and concatenation of multiple sources)
ChromicPDF is tested in the following configurations:
Elixir | Erlang/OTP | Distribution | Chromium | Ghostscript |
---|---|---|---|---|
1.15.7 | 26.2 | Alpine 3.18 | 119.0.6045.159 | 10.02.0 |
1.14.5 | 25.3.1 | Alpine 3.17 | 112.0.5615.165 | 10.01.1 |
1.14.0 | 25.1 | Alpine 3.16 | 102.0.5005.182 | 9.56.1 |
1.14.0 | 25.1 | Debian Buster | 90.0.4430.212-1 | 9.27 |
1.11.4 | 22.3.4.26 | Debian Buster | 90.0.4430.212-1 | 9.27 |
ChromicPDF is a supervision tree (rather than an application). You will need to inject it into the supervision tree of your application. First, add ChromicPDF to your runtime dependencies:
def deps do
[
{:chromic_pdf, "~> 1.15"}
]
end
Next, start ChromicPDF as part of your application:
# lib/my_app/application.ex
def MyApp.Application do
def start(_type, _args) do
children = [
# other apps...
ChromicPDF
]
Supervisor.start_link(children, strategy: :one_for_one, name: MyApp.Supervisor)
end
end
Here's how you generate a PDF from an external URL and store it in the local filesystem.
# Prints a local HTML file to PDF.
ChromicPDF.print_to_pdf({:url, "https://example.net"}, output: "example.pdf")
The next example shows how to print a local HTML file to PDF/A, as well as the use of a callback function that receives the generated PDF as path to a temporary file.
ChromicPDF.print_to_pdfa({:url, "file:///example.html"}, output: fn pdf ->
# Send pdf via mail, upload to S3, ...
end)
ChromicPDF.Template contains additional functionality for controlling page dimensions of your PDF.
[content: "<p>Hello Template</p>", size: :a4]
|> ChromicPDF.Template.source_and_options()
|> ChromicPDF.print_to_pdf()
Multiple sources can be automatically concatenated using Ghostscript.
ChromicPDF.print_to_pdf([{:html, "page 1"}, {:html, "page 2"}], output: "joined.pdf")
- There is an outdated example of how to integrate ChromicPDF in a Phoenix application, see examples/phoenix.
This should get you started:
mix deps.get
mix test
For running the full suite of integration tests, please install and have in your $PATH
:
verapdf
- For
pdfinfo
andpdftotext
, you needpoppler-utils
(most Linux distributions) or Xpdf (OSX) - For the odd ZUGFeRD test in
zugferd_test.exs
, you need to download ZUV and set the$ZUV_JAR
environment variable.
- The PDF/A conversion is inspired by the
pdf2archive
script originally created by @matteosecli and later enhanced by @JaimeChavarriaga.
Copyright (c) 2019โ2023 Bitcrowd GmbH
Licensed under the Apache License 2.0. See LICENSE file for details.