Wicked PDF header not showing up - ruby-on-rails

Question

After already checking the Rails Gem repository for similar issues as well as Stack Overflow, I couldn't find an answer to my problem.
I'm trying to render a pdf using wicked_pdf within a Rails controller, but the header is not showing up, no matter what I do or which recommended solutions to similar issues I follow.
First and foremost, here is the development console output:
***************WICKED***************
Rendering biddings/show.pdf.html.haml within layouts/pdf
Rendered biddings/show.pdf.html.haml within layouts/pdf (0.7ms)
Rendering biddings/header_pdf.html.haml within layouts/pdf_header
Rendered biddings/header_pdf.html.haml within layouts/pdf_header (1.9ms)
"***************[\"/home/tommy/.rvm/gems/ruby-
2.5.1#igalbids/bin/wkhtmltopdf\", \"-q\", \"--encoding\", \"UTF-8\",
\"--javascript-delay\", \"500\",
\"--disable-internal-links\", \"--disable-external-links\",
\"--orientation\", \"Portrait\", \"--margin-top\",
\"50\", \"--margin-bottom\", \"25\", \"--header-html\",
\"file:////tmp/wicked_header_pdf20180801-27285-b8y5sg.html\",
\"--footer-right\", \"Página [page] de [topage]\",
\"file:////tmp/wicked_pdf20180801-27285-1jfgdd7.html\",
\"/tmp/wicked_pdf_generated_file20180801-27285-1bkrvhx.pdf\"]***************"
Rendering text template
Rendered text template (0.1ms)
Sent data Licitación_2524.pdf (0.6ms)
Completed 200 OK in 2334ms (Views: 0.5ms | ActiveRecord: 64.4ms)
As you can see, both the header layout and its contents are being rendered and processed, however they don't make the final output PDF, and I don't know why! Look:
So, here's my controller code:
class Api::V1::Biddings::PdfBiddingsController < PdfController
# JWT Authentication enforced
before_action :authenticate_user!
# GET /biddings/:id/pdf
def show
#bidding = scoped_collection.find(params[:id])
authorize [:biddings, :pdf, #bidding]
respond_to do |format|
format.pdf do
render(
pdf: "#{Bidding.model_name.human}_#{#bidding.code}",
disposition: "inline",
orientation: "Portrait",
template: 'biddings/show.pdf.html.haml',
header: {
html: {
template: "biddings/header_pdf.html.haml",
handlers: [:haml],
layout: "pdf_header",
formats: [:haml, :html]
}
},
footer: {
html: {
handlers: [:haml],
layout: "pdf",
formats: [:haml, :html],
encoding: 'UTF-8'
},
right: "#{I18n.t('pdf.page')} [page] #{I18n.t('pdf.of')} [topage]"
},
margin: { :top => 50, :bottom => 25},
handlers: [:haml],
layout: "pdf",
javascript_delay: 500,
encoding: 'UTF-8',
show_as_html: false,
disable_internal_links: true,
disable_external_links: true) and return
end
end
end
protected
def self.model
Bidding
end
private
def scoped_collection
policy_scope([:biddings, :pdf, Bidding]).includes(:bidding_type, :client, :payment_condition, :price_list, :real_payment_condition, :sales_man, :user)
end
def records_per_page
params[:per_page] || 10
end
end
Nothing fancy, there you can see all the config options, pretty standard. Needless to say, the footer with the page numbering IS working fine (screenshot too long to show, but trust me). Can't say the same about the header.
Here's the PDF header layout file:
pdf_header.html.haml:
!!! 5
%html
%head
%meta{:content => "text/html; charset=utf-8", "http-equiv" => "content-type"}/
= wicked_pdf_stylesheet_link_tag "bidding_pdf", media: :all
= csrf_meta_tags
%body.pdf
= yield
and here the contents for the header "contents" per se:
header_pdf.html.haml:
Test text
Just plain text. I have a Linux 16.04 x64 OS, wicked_pdf (1.1.0), wkhtmltopdf-binary (0.12.4). How can I debug this?

Answer 1

For anyone who bumps in this, since OP's answer is not too precise, what did the job for me was including a DOCTYPE HTML tag in your header/footer. Went from invisible header (with text that could be found using the search tool), to fully rendered.

Answer 2

For anyone else reaching here... it was a CSS issue. The header was there but "invisible" and no matter what margin I set on the render options it was a CSS issue. After starting the CSS from scratch, the header appeared! I could not debug it with the flag show_as_html: true because header and footer are not rendered in that mode, only the body.
If anyone reads this and happens to be in the same situation, use the search tool in the PDF document to find a word you know that's in the header. If it finds something but it's invisible, then you know you have a CSS problem.
Also don't forget to check if you included in the html of the header the <!DOCTYPE html>. Thanks #joaolell for this.
Another thing to check, is that you have the version with patched qt of the wkhtmltopdf library (0.12.4 and above) that supports header and footer. Previous versions won't

Answer 3

Upgrade wkhtmltopdf binary to at least version "0.12.4 (with patched qt)". I just spent half a day troubleshooting because my version of 0.12.1 did not support header and footer.
Ref: Wicked pdf not rendering header/footer