Making wkhtmltopdf and chrome-headless available through an API
This project uses Elixir/Phoenix to expose a pretty simple API that renders PDFs from either HTML or URLs.
There's only one endpoint which can be called as GET and POST.
GET /api/generatePOST /api/generate
Both will result in a HTTP response which contains a PDF in the body.
HTTP/1.1 200 OK
Content-Disposition: attachment; filename=
Content-Type: application/pdf
cache-control: max-age=0, private, must-revalidate
content-length: 7557
date: Tue, 04 Jun 2019 11:17:17 GMT
server: Cowboy
x-request-id: FaT6t7TJQHHXZtcAAABD
%PDF-1.4
…Send some html (or SVG in this case) as file upload and get back a PDF.
curl -F "html=@\"ticket.svg\"" -XPOST http:/127.0.0.1:4000/api/generate\?generator=chrome --output ticket.pdfBoth GET and POST parameters are accepted. For HTML to sent directly to the
endpoint, POST is recommended.
-
takes either parameter
htmlwith some HTML string or parameterurlwith some URL that returns atext/htmlpage to be rendered as PDFs. -
filenameif you like to have filename set for downloads. Handy for Download links. -
generator: can be eitherwkhtmltopdf(default) orchrome(for chrome-headless). wkhtmltopdf's results are usually smaller while crome supports more features (for JS-rendering, use chrome) -
page_size: "A4" and "A5" are currently supported -
paper_height: set a custom paper height in inches (chrome only) -
paper_width: set a custom paper width in inches (chrome only)
Both wkhtmltopdf and chrome-headless support many more options but this is the whitelisted options that I need right now. Since options are passed as command-line paramters, I'll stick to whitelisting in fear of shell-injections.
# build image
docker build -t pdf-server .
# run image, listen on port 4000
docker run -p 4000:4000/tcp -d --name pdf-server-rel pdf-server
# generate simple "hello" PDF
curl 'http://127.0.0.1:4000/api/generate?html=<html><body><h1>Hello' --output hello.pdfSee install.bash for a cound-init.sh-compatible script to
have a śerver configured, up and running from a scratch Ubuntu 18.