wicked_pdf Error: PDF could not be generated

I had wkhtmltopdf-binary already in gemfile, but as this was working on my local computer and not on server, I left this error for the server support team to care off.. they have checked the path to wkhtmltopdf, they tried to convert a simple html to pdf and it worked.. so they tried to run a bundle update command and after this the pdf converting worked fine on server too. I had a gem path changed and I guess this was the problem. I posted my solution in case someone else will have this problem too.

I had the same problem. I had wkhtmltopdf-binary installed and bundle update didn't help neither. Here is what helped me:

The important thing is that I run this on Alpine Linux and it does not seem to be supported by gem wkhtmltopdf_binary_gem https://github.com/zakird/wkhtmltopdf_binary_gem/issues/53

I installed separately wkhtmltopdf into the system: apk add wkhtmltopdf

And then edited the initializer to include the binary path:

# config/initializers/wicked_pdf.rb
require "wicked_pdf"

WickedPdf.config = {
  exe_path: ENV["WKHTMLTOPDF_BIN"]
}

I had the same problem. The solution was to add wkhtmltopdf-binary to the gem file and run bundle install.

gem "wicked_pdf"
gem "wkhtmltopdf-binary"

For Alpine 3.9+ the wkhtmltopdf binary is available, however I was getting either a blank PDF or "Failed to load document" error - despite working fine locally on MacOSX. It turns out that you need to include fonts explicitly for alpine builds (at least)

Controller action

def show
    respond_to do |format|
      format.html do
        render 'pdfs/templates/my_template.html.erb'
      end

      format.pdf do
        render(
          pdf: "file_name",
          template: 'pdfs/templates/my_template.html.erb',
          disposition: 'inline'
        )
      end
    end
end

The above worked locally on MacOSX machine but on a server based on ruby alpine image, as below, it failed with failed to load document

Dockerfile

FROM ruby:2.6.3-alpine3.10
....
# add wkhtmltopdf for use with wicked_pdf gem
RUN apk --no-cache add wkhtmltopdf
...

even a more basic example failed with a blank pdf

respond_to do |format|
  format.pdf do
    pdf = WickedPdf.new.pdf_from_string('TESTING 123')
    send_data(
      pdf,
      filename: "file_name.pdf",
      type: 'application/pdf',
      disposition: 'inline'
    )
  end
end

Solution

Dockerfile

FROM ruby:2.6.3-alpine3.10
....
# add wkhtmltopdf for use with wicked_pdf gem
RUN apk --no-cache add \
                  ttf-ubuntu-font-family \
                  wkhtmltopdf
...

Ideally Alpine would include a basic font with the wkhtmltopdf package, however until such time I found this to be a useful source of info and/or good for adding a mutistage Docker file.

https://github.com/madnight/docker-alpine-wkhtmltopdf/blob/master/Dockerfile

NOTE:

lack of an explicit font package in alpine may also cause PDF conversion using libreoffice to fail too. We found corrupt PDFs when converted from docx files in particular.