If you are developing an E-Business web application , where you have to provide online payment solution to your customer then PayPal is one of the most secure , faster and easier way to make payment online .

In this blog, we will have a basic idea that how easily you can integrate PayPal functionality in your Liftweb project using Scala .
We are assuming that you are aware with the basics of LiftWeb and Scala .

Lift provides integration support for both PDT(Payment Data Transfer)  and IPN(Instant Payment Notification) . You do not need to add any extra functionality to handle response from PayPal .
Payment Data Transfer :

PDT(Payment Data Transfer) provides you some transaction details to be displayed to buyer , when page is redirected after completing transaction . To use PDT , you must enable AUTO RETURN .
IPN(Instant Payment Notification):

Once transaction is complete , IPN(Instant Payment Notification) sends a notification to your server with all specific details about completed transaction .

PayPal Environment setup :
Before implementing PayPal in your application , you must setup PayPal environment .

• Go To https://developer.paypal.com
• Set up both a “preconfigured seller” and “preconfigured buyer” account in the sandbox.
• Log into the sandbox as the seller account you just created, and enable Auto Return in the selling preferences.
• Enable PayPal Data Transfer (it’s on the same screen as the Auto Return configuration).
• Edit the IPN callback URL and enable IPN.

LiftWeb Environment setup :

• Add PayPal repository in your build.sbt

  "net.liftmodules" % "paypal_2.9.2" % "2.5-SNAPSHOT-1.2-SNAPSHOT"

• Let’s create PayPal Handler class which implements two traits PaypalIPN and PaypalPDT.

  object PaypalHandler extends PaypalIPN with PaypalPDT with Loggable {
    import PaypalTransactionStatus._
    val paypalAuthToken = "yourtokengoeshere"
    def pdtResponse = {
      case (info, resp) => info.paymentStatus match {
        case Full(CompletedPayment) =>
          DoRedirectResponse.apply("/paypal/success")
        case _ => DoRedirectResponse.apply("/paypal/failure")
      }
    }
   
    def actions = {
      case (CompletedPayment,info,_) =>
        //Update your transaction detail
      case (FailedPayment,info,_) =>
        //Update your transaction detail
      case (status, info, resp) =>
    }
  }
  

• Now add following lines in your Boot.Scala to initialize the PaypalRules object that contains configuration .

  ...........
  PaypalRules.init
  PaypalHandler.dispatch.foreach(LiftRules.dispatch.append(_))
  ...........
  

• Now add Buy Now button to instantiate the transaction process .
  

  Compose the BuyNowSnippet with your snippet:

   
  class TrasanctionSummary extends BuyNowSnippet {
  .........
  override val values = Map(
      "business" -> "test@business.com",
      "item_number" -> reference,
      "item_name" -> ("Auction Order: " + reference))
  .................
  }
  

  Above lines are required to implement the button .

• Finally add PayPal response pages to the SiteMap .

   
  ..............
  Menu("Transaction Complete") / "paypal" / "success"
  >> LocGroup("public") >> Hidden,
  Menu("Transaction Failure") / "paypal" / "failure"
  >> LocGroup("public") >> Hidden,
  ...........