Rails 3.0 PDFKit, include asset and image_tag when generating PDF trought a rake task

Question

I'm using rails 3.0 and PDFKit. SASS and HAML but I don't have the asset pipeline implemented yet.

If I make a call from a controller I can generate perfect styled pdf with images, calling PDFKit.new passing render_to_string :show. But if I do the same through a rake task, my PDF is generated without styles, and image_tag helper throws an error like this:

can't convert nil into String

Surely, I'm doing something wrong in the rake task... but everything works in the controller... What I'm missing? Should I include something in the rake task? or maybe use another view with inline styles and absolute paths? the calls are these:

CONTROLLER VERSION

def generate_html_invoice
  render_to_string :show, layout: 'mypdflayout'
end

mypdf = PDFKit.new html_generator

RAKE TASK VERSION

def generate_html_invoice
  invoice_view = ActionView::Base.new(MyWeb::Application.config.paths["app/views"].first)
  invoice_view.assign({ ....... various params here})
  html_invoice = invoice_view.render(template: "invoices/show", layout: 'mypdflayout')
return html_invoice

mypdf = PDFKit.new html_generator

The same error is thrown by image_tag helper and stylesheet_link_tag helper

An alternative way could be instantiate the controller in the rake task but.. is it possible? and, is it a good practice?

score 1 · Accepted Answer · answered May 14 '13 at 14:33

I couldn't find any decent solution to this, but I tried the following techniques:

QUICK AND DIRTY

change the view using %link and %img HAML tags instead the helpers, using the absolute path to the files.

SLOW BUT ELEGANT

In the rake task, call the controller to receive the view url and give it to PDFKit in this way

url = "#{(Rails.env.production? ? 'http://www.example.com' : 'http://localhost')}/invoce/#{invoice.id}"
path_to_pdf = "root/......./mypdf.pdf"
invoce_page = PDFKit.new url
invoce_page.to_file(path_to_pdf)

This one is the solution I choose. I know, it's a little dumb: the controller calls a rake task which calls the controller again... And it makes a lot of http request to the server. But in this way I can have a underground process to generate PDF invoices without waiting for the response.

I think I don't have to worry about overcharging the server because the request will be queued normally.

Rails 3.0 PDFKit, include asset and image_tag when generating PDF trought a rake task

1 Answers1