Admin Documentation

PDF Rendering

By default BookStack uses dompdf to export pages as PDF documents. The benefit of using dompdf is that it doesn’t require any additional installation or setup but the rendering capabilities are somewhat limited.

As an alternative you can use wkhtmltopdf to generate PDF documents instead. wkhtmltopdf uses the Qt WebKit rendering engine to provide a more accurate overall result, but comes with additional security concerns to be aware of.

Using wkhtmltopdf

Pre-compiled binaries for wkhtmltopdf can be found on the downloads page of their website. BookStack will check for a file named wkhtmltopdf at the base folder of a BookStack install. If found it will use that to render PDF exports. If that does not exist it will check for a WKHTMLTOPDF variable in the .env file. You can use the below variable in your .env file to set an alternate location to wkhtmltopdf:

WKHTMLTOPDF=/home/user/bins/wkhtmltopdf

If neither of those exist, or if the below mentioned security option is not enabled, the default dompdf renderer will be used instead.

Note: As of BookStack v21.08 the ALLOW_UNTRUSTED_SERVER_FETCHING must also be set to true for wkhtmltopdf to be enabled, without this dompdf will be used instead. This change was made for security since, in many cases, wkhtmltopdf will perform fetches to external URLs which may be defined by users. You should only enable the below option in environments where users & visitors are trusted.

ALLOW_UNTRUSTED_SERVER_FETCHING=true

See our security page for more detail regarding this option.

Export Page Size

By default PDF exports are generated at an A4 size. If you’d prefer exports to be generated at “US Letter” standard sizes you can specify this within your .env like so:

# US Letter
EXPORT_PAGE_SIZE=letter