Wicked_PDF render a string from a template in a background process - ruby-on-rails-3

Question

I've got a controller "tech" that has an action to email and invoice, from there we use Delayed::Job.enqueue to shove the actual email action into a background process which will be handled via a worker dyno on Heroku.
This is all working fine.
The trouble that I found is that my generated PDF invoice lives over on the Heroku Web Dyno file system and the Worker has no idea where this is.
I will do upload the PDF during the generation process, it takes too damn long.
So I need to create the invoice over on the worker dyno when it goes to execute the mailer action to send the message.
I found this blog with some detailed instructions on creating the pdf from a string: http://viget.com/extend/how-to-create-pdfs-in-rails
But it's not working at all for me, here is the code:
html = render_to_string(:action =>":show", :layout => "invoice.html")
#pdf = WickedPdf.new.pdf_from_string(html)
And the error:
"last_error"=>"undefined method `response_body=' for #<MailSenderJob:0x007fdf7e70a638>
I know this is from the docs:
WickedPdf.new.pdf_from_string(
render_to_string('templates/pdf.html.erb', :layout => 'pdfs/layout_pdf'),
:footer => {
:content => render_to_string(:layout => 'pdfs/layout_pdf')
}
)
And that code has never worked for me at all.
What I'm getting over and over is the response_body= error. It's like it's not getting a response at all.
At the top of my file I'm doing:
include ActionController::Rendering
Because this is the module that has the render_to_string method inside it.
Any help at all - please keep in mind in your response that I'm running this code on a Heroku WORKER dyno - so if there's any dependency that I need to manually include that is naturally included on the web server, please let me know.

Answer 1

I ended up having to do some weird stuff with this to finally get it working.
html = File.read(Rails.root.join('app','views','technician','invoice.html.erb'))
html = ERB.new(html).result(binding)
html = html.gsub!(/\0/,'') # There is a null byte in the rendered html, so we'll strip it out (this is kind of a hack)
# Render the PDF - we're on a worker dyno and have no access to the pdf we rendered already on the web dyno
#pdf = WickedPdf.new.pdf_from_string(
html,
:handlers => [:erb],
:footer => {
:center => "Copyright 2014"
},
:disable_smart_shrinking => true,
)
#pdf = #pdf.gsub!(/\0/,'') # Again with the null bytes!

Answer 2

Using Partials.
I know what you mean, it gets a little funky when you're rendering PDFs in the background job as opposed to a Controller action.
I thought I would share my implementation as a comparison and for others to get another example from.
notification_mailer.rb
def export
header_html = render_to_string( partial: 'exports/header.pdf.erb',
locals: { report_title: 'Emissions Export' } )
body_html = render_to_string( partial: "exports/show.pdf.erb" )
footer_html = render_to_string( partial: 'exports/footer.pdf.erb' )
#pdf = WickedPdf.new.pdf_from_string(
body_html,
orientation: 'Landscape',
margin: { bottom: 20, top: 30 },
header: { content: header_html },
footer: { content: footer_html } )
# Attach to email as attachment.
attachments["Emissions Export.pdf"] = #pdf
# Send email. Attachment assigned above will automatically be included.
mail( { subject: 'Emissions Export PDF', to: 'elon#musk.com' } )
end