create a (Prawn) PDF inside custom DelayedJob and upload it to S3? - amazon-s3

Question

Using: Rails 4.2, Prawn, Paperclip, DelayedJobs via ActiveJobs, Heroku.
I have a PDF that is very large and needs to be handled in the background. Inside a custom Job I want to create it, upload it to S3, and then email the user with a url when its ready. I facilitate this via a PdfUpload model.
Is there anything wrong with my approach/code? Im using File.open() as outlined in examples I found, but this seems to be the root of my error ( TypeError: no implicit conversion of FlightsWithGradesReport into String ).
class PdfUpload < ActiveRecord::Base
has_attached_file :report,
path: "schools/:school/pdf_reports/:id_:style.:extension"
end
/pages_controller.rb
def flights_with_grades_report
flash[:success] = "The report you requested is being generated. An email will be sent to '#{ current_user.email }' when it is ready."
GenerateFlightsWithGradesReportJob.perform_later(current_user.id, #rating.id)
redirect_to :back
authorize #rating, :reports?
end
/ the job
class GenerateFlightsWithGradesReportJob < ActiveJob::Base
queue_as :generate_pdf
def perform(recipient_user_id, rating_id)
rating = Rating.find(rating_id)
pdf = FlightsWithGradesReport.new( rating.id )
pdf_upload = PdfUpload.new
pdf_upload.report = File.open( pdf )
pdf_upload.report_processing = true
pdf_upload.report_file_name = "report.pdf"
pdf_upload.report_content_type = "application/pdf"
pdf_upload.save!
PdfMailer.pdf_ready(recipient_user_id, pdf_upload.id)
end
end
This results in an error:
TypeError: no implicit conversion of FlightsWithGradesReport into String

Answer 1

Changing this:
pdf_upload.report = File.open( pdf )
to this:
pdf_upload.report = StringIO.new(pdf.render)
fixed my problem.