Rails: QR code generating with rqrcode

Creating and rendering QR codes in rails app is easy now. rqrcode gem provides this functionality. Follow this tutorial. At the end, you will be having a QR code rendered on your app. Scanning that code will ask you to open Googlein browser. You may replace the URL as you need.

Installing

Add this line to your application’s Gemfile:

gem 'rqrcode'

or install manually:

gem install rqrcode

Basic usage example

You can use this helper: /helpers/qrcode_helper.rb

module QrcodeHelper
  require 'rqrcode'

  def render_qr_code text, size = 3
    return if text.to_s.empty?
    qr = RQRCode::QRCode.new(text)
    sizeStyle = "width: #{size}px; height: #{size}px;"

    content_tag :table, class: "qrcode pull-right" do
      qr.modules.each_index do |x|
        concat(content_tag(:tr) do
          qr.modules.each_index do |y|
            color = qr.qrcode.checked?(x, y) ? 'black' : 'white'
            concat content_tag(:td, nil, class: color, style: sizeStyle)
          end
        end)
      end
    end
  end
end

Into your view some_view.html.erb

<%= render_qr_code("https://www.google.com/") %>

And you need to add style for your code qrcode.css.scss

table.qrcode {
  border-width: 0;
  border-style: none;
  border-color: #0000ff;
  border-collapse: collapse;
  margin-top: 100px;
  margin-bottom: 12px;

  td {
    border-width: 0;
    border-style: none;
    border-color: #0000ff;
    border-collapse: collapse;
    padding: 0;
    margin: 0;
    width: 3px;
    height: 3px;

    &.black {
      background-color: #000 !important
    }

    &.white {
      background-color: #fff !important
    }
  }
}

Reload the webpage and scan the QR code. We’re done..!