123ish

<# /app/views/users/activate_2fa.html.erb %>
<%= @svg.html_safe %>
<%= form_for(@user, url: activate_2fa_update_path) do |f| %>
  <%= f.text_field :otp_response_code %>
  <%= f.submit %>
<% end %>

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gem 'devise', '~> 4.7.1'
gem 'active_model_otp', '~> 2.0.1'
gem 'rqrcode', '~> 1.1.2

123ish

# /app/controllers/users/sessions_controller.rb
class Users::SessionsController < Devise::SessionsController
 
  def create
    self.resource = resource_class.find_for_authentication(sign_in_params.except(:password, :otp_response_code))
    if resource
      if resource.active_for_authentication?
        if resource && resource.otp_module_disabled?
          continue_sign_in(resource, resource_name)
        elsif resource && resource.otp_module_enabled?

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<%# /app/views/users/sessions/two_factors_authentication.html.erb %>
<%= form_for(resource, :as => resource_name, :url => session_path(resource_name), :html => { :role => 'form', :method => 'POST' }) do |f| %>
  <%= f.hidden_field :email, value: params[:user][:email] %>
  <%= f.text_field :otp_response_code %>
  <%= f.submit %>
<% end %>

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# app/controllers/users_controller.rb
class UsersController < ApplicationController  
  def activate_2fa
    qrcode = RQRCode::QRCode.new(current_user.provisioning_uri(nil, issuer: 'your-app-url.com'), :size => 12, :level => :h)
    @svg = qrcode.as_svg(offset: 0, color: '000', 
                    shape_rendering: 'crispEdges', 
                    module_size: 4)   
    respond_to :html
  end
  

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gem 'bullet', '~> 6.1.0'

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config.after_initialize do
  Bullet.enable = true
  Bullet.alert = true
  Bullet.bullet_logger = true
  Bullet.console = true
  Bullet.rails_logger = true
  Bullet.add_footer = true
end

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group :optimization do
  gem 'bullet', '~> 6.1.0'
end

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# config/initializers/mime_types.rb
Mime::Type.register 'text/html', :amp

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# app/controllers/samples_controller.rb
Class SamplesController
  # other existing methods

  def show
    # your existing codes
    respond_to do |format|
      format.html
      format.amp { render 'amp/samples/show.amp', layout: 'amp/layouts/application' }
    end