class OffsitePayments::Integrations::Paypal::Notification

end
end
render :nothing
end
end
order.save
ensure
raise
order.status = ‘failed’
rescue => e
end
logger.error(“Failed to verify Paypal’s notification, please investigate”)
else
shop.ship(order)
order.status = ‘success’
if notify.complete? and order.total == notify.amount
begin
if notify.acknowledge
order = Order.find(notify.item_id)
end
masspay_items = notify.items
if notify.masspay?
notify = Paypal::Notification.new(request.raw_post)
def paypal_ipn
include OffsitePayments::Integrations
class BackendController < ApplicationController
Example
on creating a safe payment controller.
is an example, please read the Paypal API documentation for all the details
The Example shows a typical handler in a rails application. Note that this
Parser and handler for incoming Instant payment notifications from paypal.

def account 

def account
  params['business'] || params['receiver_email']
end

def acknowledge(authcode = nil)

end
... log possible hacking attempt ...
else
... process order ... if notify.complete?
if notify.acknowledge

notify = PaypalNotification.new(request.raw_post)
def paypal_ipn

Example:

ok or a fail.
ipn arrives. Paypal will verify that all the information we received are correct and will return a
Acknowledge the transaction to paypal. This method has to be called after a new 
def acknowledge(authcode = nil)
  payload =  raw
  response = ssl_post(Paypal.service_url + '?cmd=_notify-validate', payload,
    'Content-Length' => "#{payload.size}",
    'User-Agent'     => "Active Merchant -- http://activemerchant.org"
  )
  raise StandardError.new("Faulty paypal result: #{response}") unless ["VERIFIED", "INVALID"].include?(response)
  response == "VERIFIED"
end

def complete?

Was the transaction complete? 
def complete?
  status == "Completed"
end

def currency

What currency have we been dealing with 
def currency
  params['mc_currency']
end

def fee

the markup paypal charges for the transaction 
def fee
  params['mc_fee']
end

def gross

the money amount we received in X.2 decimal. 
def gross
  params['mc_gross']
end

def initialize(post, options = {}) 

def initialize(post, options = {})
  super
  extend MassPayNotification if masspay?
end

def invoice

This is the invoice which you passed to paypal 
def invoice
  params['invoice']
end

def item_id

doesn't return item_number in dispute notifications
The custom field is also mapped to item_id because PayPal
This is the item number which we submitted to paypal 
def item_id
  params['item_number'] || params['custom']
end

def masspay?

Is it a masspay notification? 
def masspay?
  type == "masspay"
end

def received_at

times an hour to inform us about the notification
One possible scenario is that our web application was down. In this case paypal tries several
sometimes it can happen that we get the notification much later.
When was this payment received by the client. 
def received_at
  parsed_time_fields = DateTime._strptime(params['payment_date'], "%H:%M:%S %b %d, %Y %Z")
  Time.gm(
    parsed_time_fields[:year],
    parsed_time_fields[:mon],
    parsed_time_fields[:mday],
    parsed_time_fields[:hour],
    parsed_time_fields[:min],
    parsed_time_fields[:sec]
  ) - Time.zone_offset(parsed_time_fields[:zone])
end

def status

Voided::
Reversed::
Refunded::
Processed::
Pending::
Partially-Refunded::
In-Progress::
Failed::
Expired::
Denied::
Completed::
Canceled-Reversal::
Status of transaction. List of possible values: 
def status
  params['payment_status']
end

def test?

Was this a test transaction? 
def test?
  params['test_ipn'] == '1'
end

def transaction_id

Id of this transaction (paypal number) 
def transaction_id
  params['txn_id']
end

def type

"cart" "send_money" "web_accept" are possible here.
What type of transaction are we dealing with? 
def type
  params['txn_type']
end