Rails app hangs when using Wicked_pdf gem and wkhtmltopdf-binary-edge - ruby-on-rails

Question

I'm trying to print a PDF of my view by using the `'wicked_pdf' gem. This is the first time I use this gem. I've read the the documentation and googled around and I also found some simular questions here on Stack Overflow But nothing seems to do the trick.
I've validated the binaries ( see edit below) they are working fine, so the problem isn´t there.
I found two strange lines in the terminal when running rails s( See edit at the bottom)
I've been searching for a solution to this for three straight days, and can't figure this out.
Am I missing something here?
the server constantly hangs with that output in the terminal
Rendered pages/partials/_travel_part.html.erb (36.6ms)
Rendered users/show.html.erb within layouts/application (531.7ms)
Rendered layouts/_navbar.html.erb (2.6ms)
Rendered shared/_footer.html.erb (0.8ms)
Completed 200 OK in 1640ms (Views: 1115.4ms | ActiveRecord: 136.0ms)
"***************[\"/usr/local/bin/wkhtmltopdf\", \"-q\", \"file:////var/folders/sm/zwm8cy0x73qb6q1pq22r4bjh0000gn/T/wicked_pdf20160913-35465-hkw9b8.html\", \"/var/folders/sm/zwm8cy0x73qb6q1pq22r4bjh0000gn/T/wicked_pdf_generated_file20160913-35465-10go9dt.pdf\"]***************"
Below is what I have so far.
I want to print views/users/show.html.erb so in the users_controller.rb I have this code in the showmethod
def show
#user = User.find(params[:id])
#users = User.order('created_at DESC').paginate(page: params[:page], per_page: 30)
#paper = current_user.papers.build
#electro = current_user.electros.build
#hwater = current_user.hwaters.build
#cleaning = current_user.cleanings.build
#transport = current_user.transports.build
#papers = current_user.papers
respond_to do |format|
format.html {render layout:'application'}
format.pdf {render pdf:"test",javascript_delay:2000,
layout:'application',template:'users/show.pdf.erb'}
end
end
In the application.html.erbI have this in the head using the wicked pdf helper
<%= wicked_pdf_stylesheet_link_tag 'application', media: 'all', 'data-turbolinks-track' => true %>
<%= wicked_pdf_javascript_include_tag 'application', 'data-turbolinks-track' => true %>
<%= javascript_include_tag "http://www.google.com/jsapi"%>
<%= wicked_pdf_javascript_include_tag 'chartkick'%>
<%= csrf_meta_tags %>
The button in the views/users/show.html.erb is
<%= link_to 'Download Pdf', user_path(current_user, format: :pdf) %>
in the config/initializers/mime_types.rb I have this code
Mime::Type.register "application/pdf", :pdf
in the config/initializers/wicked_pdf.rb I have this code
WickedPdf.config = {
#:wkhtmltopdf => '/usr/local/bin/wkhtmltopdf',
#:layout => "pdf.html",
:exe_path => '/usr/local/bin/wkhtmltopdf'
}
And in the gemfile.rb I have those two gems:
gem 'wicked_pdf', '~> 1.0', '>= 1.0.6'
gem 'wkhtmltopdf-binary-edge'
EDIT*
Ok I've Validated the binaries are working fine by typing this wkhtmltopdf google.com google in the terminal. So my conclusion is that the problem lies somewhere else than in the wkhtmltopdf. But where? I still can't find out...
(AddingWickedPdf) $ wkhtmltopdf google.com google
Loading pages (1/6)
Counting pages (2/6)
Resolving links (4/6)
Loading headers and footers (5/6)
Printing pages (6/6)
Done
(AddingWickedPdf) $
ANOTHER EDIT
I noticed this lines in the terminal when I started my server rails s earlier to night, I don´t know what it means, but I'm sure it has something to do with the App hanging when rendering pdf:
/Users/dadi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/actionpack-4.2.5/lib/action_dispatch/http/mime_type.rb:163: warning: already initialized constant Mime::PDF
/Users/dadi/.rbenv/versions/2.2.3/lib/ruby/gems/2.2.0/gems/actionpack- 4.2.5/lib/action_dispatch/http/mime_type.rb:163: warning: previous definition of PDF was here
It would be so great if someone could take a look at this and guide me to the right path here.
thanks in advance
DH

Answer 1

The answer was originally posted here:
How rails resolve multi-requests at the same time?
Subsequently adapted for this question here (Last answer):
PDFkit hangs when generating a pdf with an image