sPDF

sPDF ( pronounced speedy-f ) is a Scala library that makes it super easy to create complex PDFs from plain old HTML, CSS and Javascript.

On the backend it uses wkhtmltopdf which renders HTML using Webkit.

sPDF is heavily inspired by Ruby's PdfKit gem.

The main features of sPDF are:

full support of wkhtmltopdf extended parameters (see the source of the PdfConfig trait)
can read HTML from several sources: java.io.File, java.io.InputStream, java.net.URL, scala.xml.Elem, and String
can write PDFs to File and OutputStream

The source HTML can reference to images and stylesheet files as long as the URLs point to the absolute path of the source file. It's also possible to embed javascript code in the pages, wkhtmltopdf will wait for the document ready event before generating the PDF.

Installation

Add the following to your sbt build for Scala 2.10, 2.11 and 2.12:

libraryDependencies += "io.github.simplifier-ag" %% "spdf" % "1.4.1"

Usage

import java.io._
import java.net._

// Create a new Pdf converter with a custom configuration
// run `wkhtmltopdf --extended-help` for a full list of options
val pdf = Pdf(new PdfConfig {
  orientation := Landscape
  pageSize := "Letter"
  marginTop := "1in"
  marginBottom := "1in"
  marginLeft := "1in"
  marginRight := "1in"
})

val page = <html>
  <body>
    <h1>Hello World</h1>
  </body>
</html>

// Save the PDF generated from the above HTML into a Byte Array
val outputStream = new ByteArrayOutputStream
pdf.run(page, outputStream)

// Save the PDF of Google's homepage into a file
pdf.run(new URL("http://www.google.com"), new File("google.pdf"))

If you want to use sPDF in headless mode on debian you'll need to call to wkhtmltopdf through a virtualizer like xvfb-run. This is because wkhtmltopdf does not support running in headless mode on debian through the apt package. To use sPDF in this kind of environment you need to use WrappedPdf instead of Pdf. For Example:

import java.io._
import java.net._

// Create a new Pdf converter with a custom configuration
// run `wkhtmltopdf --extended-help` for a full list of options
val pdf = WrappedPdf(Seq("xvfb-run", "wkhtmltopdf"), new PdfConfig {
  orientation := Landscape
  pageSize := "Letter"
  marginTop := "1in"
  marginBottom := "1in"
  marginLeft := "1in"
  marginRight := "1in"
})

val page = <html>
  <body>
    <h1>Hello World</h1>
  </body>
</html>

// Save the PDF generated from the above HTML into a Byte Array
val outputStream = new ByteArrayOutputStream
pdf.run(page, outputStream)

// Save the PDF of Google's homepage into a file
pdf.run(new URL("http://www.google.com"), new File("google.pdf"))

Installing wkhtmltopdf

Visit the wkhtmltopdf downloads page and install the appropriate package for your platform.

Troubleshooting

NoExecutableException

Make sure wkhtmltopdf is installed and your JVM is running with the correct PATH environment variable.

If that doesn't work you can manually set the path to wkhtmltopdf when you create a new Pdf instance:

val pdf = Pdf("/opt/bin/wkhtmltopdf", PdfConfig.default)

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).

Notes

Asynchronous conversion

sPDF relyies on Scala's scala.sys.process.Process class to execute wkhtmltopdf and pipe input/output data.

The execution of wkhtmltopdf and thus the conversion to PDF is blocking. If you need the processing to be asynchronous you can wrap the call inside a Future.

val pdf = Pdf(PdfConfig.default)

val result = Future { pdf.run(new URL("http://www.google.com"), new File("google.pdf")) }

Contributing

Fork the project.
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 build settings, version, or history.
Send me a pull request. Bonus points for topic branches.

Release / Publish

release cross with-defaults
check out released version
publishSigned
sonatypeRelease

Roadmap

Full support for extended options
Full support for input types
Streaming API (with scalaz-stream)
Simplified API with implicits
Integration with Play for streaming PDFs in HTTP responses

simplifier-ag / spdf 1.5.0