Verify Paystack Payments in Ruby on Rails

# app/services/paystack_service.rb (extended)
def verify_and_fulfill(reference)
  order = Order.find_by(reference: reference)
  return { error: 'Order not found' } unless order
  return { success: true, already_fulfilled: true } if order.paid?

  result = verify_transaction(reference)
  return { error: 'Verification failed' } unless result['status']
  return { error: 'Payment not successful' } unless result['data']['status'] == 'success'
  return { error: 'Amount mismatch' } if result['data']['amount'] != order.amount_kobo
  return { error: 'Currency mismatch' } if result['data']['currency'] != order.currency

  updated = Order.where(reference: reference, paid: false)
                 .update_all(paid: true, paid_at: Time.current)

  { success: true, already_fulfilled: updated == 0 }
end

def callback
  reference = params[:reference] || params[:trxref]
  return redirect_to root_path, alert: 'Missing reference' unless reference

  service = PaystackService.new
  result = service.verify_and_fulfill(reference)

  if result[:success]
    render :success
  else
    flash[:error] = result[:error]
    render :failed
  end
end

• Using update instead of update_all. update triggers callbacks and is not atomic for concurrent requests.
• Not checking currency. Always verify the currency matches your model.
• Mixing test and live keys. Both must be in the same mode.

This guide is part of the Paystack integration guides by language and framework series.

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