checkout-dates.rb

require 'stripe'
Stripe.api_key = ENV['STRIPE_SECRET_KEY']

def date_description(dates)
end

def next_dates
  # some database stuff
  [start_date, end_date]
end

checkout_session = Stripe::Checkout::Session.create({
  success_url: 'https://example.com/success',
  cancel_url: 'https://example.com/cancel',
  line_items: [{
    price_data: {
      currency: 'cad',
      unit_amount: 100000, # in cents
      product_data: {
        name: 'Product Coaching',
        description: date_description(next_dates),
      },
    },
    quantity: 1,
  }],
  mode: 'payment',
  metadata: {
    start_date: next_dates.first,
    end_date: next_dates.last
  }
})
redirect_to checkout_session.url

webhook.rb

require 'json'

# Using Sinatra
post '/webhook' do
  payload = request.body.read
  event = nil

  begin
    event = Stripe::Event.construct_from(
      JSON.parse(payload, symbolize_names: true)
    )
  rescue JSON::ParserError => e
    # Invalid payload
    status 400
    return
  end

  # Handle the event
  case event.type
  when 'checkout.session.completed', 'checkout.session.async_payment_succeeded'
    checkout_session = event.data.object
    if checkout_session.payment_status == 'paid'
      # use checkout_session.metadata.start_date and checkout_session.metadata.end_date to udpate the database
      
    end
  else
    puts "Unhandled event type: #{event.type}"
  end

  status 200
end