Create PDF’s and Images from your website in Rails 3

I am going to show you how to generate both a pdf and image from a single action in a controller using the awesome, wkhtmltopdf library. This also uses PDFKit and WebSnap gems available on GitHub.
This example assumes the following:

• wkhtmltopdf and wkhtmltoimage are already installed and accessible on in the PATH.
• You have an html page setup to display the record.
• You have created a pdf CSS file to help display the pdf, if you so choose. 

# config/initializers/mime_types.rb
  Mime::Type.register "application/pdf", :pdf
  Mime::Type.register "image/png", :png
 
  # app/controllers/items_controller.rb
  def show
    @item = Item.find(params[:id])
 
    respond_to do |format|
      format.html { }
      format.pdf {
       html = render_to_string :action => "show.html.erb"
        kit  = PDFKit.new( html, :zoom => 0.75 )
        kit.stylesheets << File.join( RAILS_ROOT, "public", "stylesheets", "pdf.css" )
 
        send_data kit.to_pdf, :filename => "item.pdf", :type => 'application/pdf', :disposition => 'inline'
      }
      format.png {
       html = render_to_string :action => "show.html.erb"
 
        # I am nil'ing these options out because my version of wkhtmltoimage does
        # not support the scale options and I do not want to crop the image at all.
        snap = WebSnap::Snapper.new(html, :format => 'png', :'scale-h' => nil, :'scale-w' => nil,
          :'crop-h' => nil, :'crop-w' => nil, :quality => 100, :'crop-x' => nil, :'crop-y' => nil)
 
        send_data snap.to_bytes, :filename => "item.png", :type => "image/png", :disposition => 'inline'
      }
    end

You should be able to access

  http://example.com/items/1 # => Generates an html page.
  http://example.com/items/1.pdf # => Generates a pdf of the html page.
  http://example.com/items/1.png # => Generates a png of the html page 

(https://github.com/siuying/websnap)