Generate and save a pdf to S3 with wicked_pdf and paperclip

estimate.rb

# Main reference was lascarides' post at http://stackoverflow.com/questions/14743447/getting-pdf-from-wickedpdf-for-attachment-via-carrierwave

# estimate.rb
# ...
  has_attached_file :pdf,
    storage: :s3,
    s3_credentials: {
      access_key_id: ENV['AWS_ACCESS_KEY_ID'],
      secret_access_key: ENV['AWS_SECRET_ACCESS_KEY'],
      bucket: ENV['AWS_BUCKET']
    },
    s3_permissions: :private,
    path: "/estimates/:id/:version/:filename"

  Paperclip.interpolates :document_type do |attachment, style|
    attachment.instance.document_type
  end
  Paperclip.interpolates :version do |attachment, style|
    attachment.instance.latest_pdf_version
  end
# ...
  
  def generate_pdf
    increment!(:latest_pdf_version)

    pdf_string = WickedPdf.new.pdf_from_string(
      ActionController::Base.new().render_to_string(
        :template => '/finance/estimate',
        :locals => {
          :@estimate => self,
          :@billing_client => billing_client,
          :@shipping_client => shipping_client,
          :@project => project
        },
        :layout => false,
      ),
      :pdf => estimate_number,
      :layout => false,
      :page_size => 'Letter',
      :lowquality => false,
      :handlers => [:erb],
      :formats => [:html],
      :margin => {:top                => 5,
                  :bottom             => 0,
                  :left               => 0,
                  :right              => 0},
      :orientation => 'Portrait',
      :disposition => 'attachment'
    )

    tempfile = Tempfile.new(["#{estimate_number}", ".pdf"], Rails.root.join('tmp'))
    tempfile.binmode
    tempfile.write pdf_string
    tempfile.close

    self.pdf = File.open tempfile.path
    self.pdf_file_name = "#{estimate_number}.pdf"
    # Store secure url on the model, valid for 90 days
    self.pdf_url = self.pdf.s3_object.url_for(:read, secure: true, expires: 90.days).to_s
    save

    tempfile.unlink

    # Only keep 5 most recent versions
    if self.latest_pdf_version > 5
      s3 = AWS::S3.new access_key_id: ENV['AWS_ACCESS_KEY_ID'], secret_access_key: ENV['AWS_SECRET_ACCESS_KEY']
      s3.buckets[ENV['AWS_BUCKET']].objects["estimates/#{self.id}/#{self.latest_pdf_version - 5}/#{self.estimate_number}.pdf"].delete
      s3.buckets[ENV['AWS_BUCKET']].objects["estimates/#{self.id}/#{self.latest_pdf_version - 5}"].delete
    end

  end