Integrate PayPal in LiftWeb application using Scala

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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,
...........