使用 Ruby on Rails 中的 gem 收据将 QR 码插入 PDF

Question

I'm using gem 'receipts' by Chris Oliver, and I want to insert QRcode with payment details (to the footer section for example). Models: Partner and Charge. I want QR code to contain model attributes, like these: charge.partner.iban, charge.amount and something like that. Charge .rb has method receipt:

  def receipt
    Receipts::Invoice.new(
      details: [
        ["Receipt Number", "123"],
        ["Date paid", Date.today],
        ["Payment method", "ACH super long super long super long super long super long"]
        ],
        company: {
          name: "Example, LLC",
          address: "123 Fake Street\nNew York City, NY 10012",
          email: "support@example.com",
          logo: File.expand_path("./app/assets/images/logo.png")
        },
        recipient: [
          self.partner.name,
          self.partner.address,
          "City, State Zipcode",
          nil,
          "customer@example.org"
        ],
        line_items: [
          ["<b>Item</b>", "<b>Unit Cost</b>", "<b>Quantity</b>", "<b>Amount</b>"],
          ["Subscription", "$19.00", "1", "$19.00"],
          [nil, nil, "Subtotal", "$19.00"],
          [nil, nil, "Tax", "$1.12"],
          [nil, nil, "Total", "$20.12"],
          [nil, nil, "<b>Amount paid</b>", "$20.12"],
          [nil, nil, "Refunded on #{Date.today}", "$5.00"]
        ],
        footer: "Thanks for your business. Please contact us if you have any questions."
      )
  end

charges_controller has:

  def show
    respond_to do |format|
      format.html
      format.json
      format.pdf { send_pdf }
    end
  end

private
    def send_pdf
      send_data @charge.receipt.render,
        filename: "#{@charge.created_at.strftime("%Y-%m-%d")}-gorails-receipt.pdf",
        type: "application/pdf",
        disposition: :inline # or :attachment to download
    end

charges/show.html.erb:

<%= link_to "View invoice", charge_path(@charge, format: :pdf) %>

I tried using prawn-qrcode, but couldn't make it. Maximum what I get is something as line of text in the footer. When I put this in receipts method:

    qrcode = RQRCode::QRCode.new(self.partner.ico.to_s)
    png = qrcode.as_png(
      resize_gte_to: false,
      resize_exactly_to: false,
      fill: 'white',
      color: 'black',
      size: 120,
      border_modules: 4,
      module_px_size: 6,
      file: nil # path to write
    )

and this in the footer: footer: ActionController::Base.helpers.image_tag(png.to_data_url)

What should I do to insert QRcode with desired data? Is there any examples of similar task? Thanks

Answer 1

Note : This is untested as-is but should work based on the documentation of the libraries themselves.

receipts uses prawn to generate pdfs.

Someone has created a QR Code renderer for prawn called prawn-qrcode which uses rqrcode so you may be able to use this as a simple bridge between the 2 libraries.

Theoretical Example:

def send_pdf
  receipt = @charge.receipt
  qr_code = RQRCode::QRCode.new(self.partner.ico.to_s)
  receipt.render_qr_code(qr_code, extent: 72)
  send_data receipt.render,
    filename: "#{@charge.created_at.strftime("%Y-%m-%d")}-gorails-receipt.pdf",
    type: "application/pdf",
    disposition: :inline # or :attachment to download
end

Additional Notes:

• You may have to play around with positioning eg render_qr_code(qr_code, pos: [x,y])
• I am not sure what self.partner.ico.to_s generates