Integration with Payment Gateways is one of the most common integration in business applications. In this post, I will demonstrate how you can integrate your Java (Servlet/JSP/Struts/Spring/etc.) applications with Paypal using Paypal Button and Instant Payment Notification (IPN).
For those who hate to read long documentation, I’ve tried to capture “minimum” reading material here from Paypal website that is required to understand Paypal IPN Protocal and Architecture; and which is a pre-requisite for our example below.
Besides that, you should also setup following (if not done already):
- Create Paypal Account
- Activate Paypal Developer Account by signing in with your Paypal Account credentials
- Create Paypal Payment Button
‘IpnHandler.java’
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| /** | |
| * Paypal Button and Instant Payment Notification (IPN) Integration with Java | |
| * http://codeoftheday.blogspot.com/2013/07/paypal-button-and-instant-payment_6.html | |
| */ | |
| package smhumayun.codeoftheday.PaypalIpnExample; | |
| import javax.net.ssl.HttpsURLConnection; | |
| import javax.servlet.http.HttpServletRequest; | |
| import java.io.BufferedReader; | |
| import java.io.InputStreamReader; | |
| import java.io.PrintWriter; | |
| import java.net.URL; | |
| import java.net.URLEncoder; | |
| import java.util.Enumeration; | |
| import java.util.Iterator; | |
| import java.util.Map; | |
| import java.util.logging.Level; | |
| import java.util.logging.Logger; | |
| /** | |
| * Paypal IPN Notification Handler Class | |
| * | |
| * User: smhumayun | |
| * Date: 7/6/13 | |
| * Time: 5:48 PM | |
| */ | |
| public class IpnHandler | |
| { | |
| private Logger logger; | |
| private IpnConfig ipnConfig; | |
| private IpnInfoService ipnInfoService; | |
| /** | |
| * This method handles the Paypal IPN Notification as follows: | |
| * 1. Read all posted request parameters | |
| * 2. Prepare 'notify-validate' command with exactly the same parameters | |
| * 3. Post above command to Paypal IPN URL {@link IpnConfig#ipnUrl} | |
| * 4. Read response from Paypal | |
| * 5. Capture Paypal IPN information | |
| * 6. Validate captured Paypal IPN Information | |
| * 6.1. Check that paymentStatus=Completed | |
| * 6.2. Check that txnId has not been previously processed | |
| * 6.3. Check that receiverEmail matches with configured {@link IpnConfig#receiverEmail} | |
| * 6.4. Check that paymentAmount matches with configured {@link IpnConfig#paymentAmount} | |
| * 6.5. Check that paymentCurrency matches with configured {@link IpnConfig#paymentCurrency} | |
| * 7. In case of any failed validation checks, throw {@link IpnException} | |
| * 8. If all is well, return {@link IpnInfo} to the caller for further business logic execution | |
| * | |
| * @param request {@link HttpServletRequest} | |
| * @return {@link IpnInfo} | |
| * @throws IpnException | |
| */ | |
| public IpnInfo handleIpn (HttpServletRequest request) throws IpnException { | |
| logger.info("inside ipn"); | |
| IpnInfo ipnInfo = new IpnInfo(); | |
| try | |
| { | |
| //1. Read all posted request parameters | |
| String requestParams = this.getAllRequestParams(request); | |
| logger.info(requestParams); | |
| //2. Prepare 'notify-validate' command with exactly the same parameters | |
| Enumeration en = request.getParameterNames(); | |
| StringBuilder cmd = new StringBuilder("cmd=_notify-validate"); | |
| String paramName; | |
| String paramValue; | |
| while (en.hasMoreElements()) { | |
| paramName = (String) en.nextElement(); | |
| paramValue = request.getParameter(paramName); | |
| cmd.append("&").append(paramName).append("=") | |
| .append(URLEncoder.encode(paramValue, request.getParameter("charset"))); | |
| } | |
| //3. Post above command to Paypal IPN URL {@link IpnConfig#ipnUrl} | |
| URL u = new URL(this.getIpnConfig().getIpnUrl()); | |
| HttpsURLConnection uc = (HttpsURLConnection) u.openConnection(); | |
| uc.setDoOutput(true); | |
| uc.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); | |
| uc.setRequestProperty("Host", "www.paypal.com"); | |
| PrintWriter pw = new PrintWriter(uc.getOutputStream()); | |
| pw.println(cmd.toString()); | |
| pw.close(); | |
| //4. Read response from Paypal | |
| BufferedReader in = new BufferedReader(new InputStreamReader(uc.getInputStream())); | |
| String res = in.readLine(); | |
| in.close(); | |
| //5. Capture Paypal IPN information | |
| ipnInfo.setLogTime(System.currentTimeMillis()); | |
| ipnInfo.setItemName(request.getParameter("item_name")); | |
| ipnInfo.setItemNumber(request.getParameter("item_number")); | |
| ipnInfo.setPaymentStatus(request.getParameter("payment_status")); | |
| ipnInfo.setPaymentAmount(request.getParameter("mc_gross")); | |
| ipnInfo.setPaymentCurrency(request.getParameter("mc_currency")); | |
| ipnInfo.setTxnId(request.getParameter("txn_id")); | |
| ipnInfo.setReceiverEmail(request.getParameter("receiver_email")); | |
| ipnInfo.setPayerEmail(request.getParameter("payer_email")); | |
| ipnInfo.setResponse(res); | |
| ipnInfo.setRequestParams(requestParams); | |
| //6. Validate captured Paypal IPN Information | |
| if (res.equals("VERIFIED")) { | |
| //6.1. Check that paymentStatus=Completed | |
| if(ipnInfo.getPaymentStatus() == null || !ipnInfo.getPaymentStatus().equalsIgnoreCase("COMPLETED")) | |
| ipnInfo.setError("payment_status IS NOT COMPLETED {" + ipnInfo.getPaymentStatus() + "}"); | |
| //6.2. Check that txnId has not been previously processed | |
| IpnInfo oldIpnInfo = this.getIpnInfoService().getIpnInfo(ipnInfo.getTxnId()); | |
| if(oldIpnInfo != null) | |
| ipnInfo.setError("txn_id is already processed {old ipn_info " + oldIpnInfo); | |
| //6.3. Check that receiverEmail matches with configured {@link IpnConfig#receiverEmail} | |
| if(!ipnInfo.getReceiverEmail().equalsIgnoreCase(this.getIpnConfig().getReceiverEmail())) | |
| ipnInfo.setError("receiver_email " + ipnInfo.getReceiverEmail() | |
| + " does not match with configured ipn email " + this.getIpnConfig().getReceiverEmail()); | |
| //6.4. Check that paymentAmount matches with configured {@link IpnConfig#paymentAmount} | |
| if(Double.parseDouble(ipnInfo.getPaymentAmount()) != Double.parseDouble(this.getIpnConfig().getPaymentAmount())) | |
| ipnInfo.setError("payment amount mc_gross " + ipnInfo.getPaymentAmount() | |
| + " does not match with configured ipn amount " + this.getIpnConfig().getPaymentAmount()); | |
| //6.5. Check that paymentCurrency matches with configured {@link IpnConfig#paymentCurrency} | |
| if(!ipnInfo.getPaymentCurrency().equalsIgnoreCase(this.getIpnConfig().getPaymentCurrency())) | |
| ipnInfo.setError("payment currency mc_currency " + ipnInfo.getPaymentCurrency() | |
| + " does not match with configured ipn currency " + this.getIpnConfig().getPaymentCurrency()); | |
| } | |
| else | |
| ipnInfo.setError("Inavlid response {" + res + "} expecting {VERIFIED}"); | |
| logger.info("ipnInfo = " + ipnInfo); | |
| this.getIpnInfoService().log(ipnInfo); | |
| //7. In case of any failed validation checks, throw {@link IpnException} | |
| if(ipnInfo.getError() != null) | |
| throw new IpnException(ipnInfo.getError()); | |
| } | |
| catch(Exception e) | |
| { | |
| if(e instanceof IpnException) | |
| throw (IpnException) e; | |
| logger.log(Level.SEVERE, e.toString(), e); | |
| throw new IpnException(e.toString()); | |
| } | |
| //8. If all is well, return {@link IpnInfo} to the caller for further business logic execution | |
| return ipnInfo; | |
| } | |
| /** | |
| * Utility method to extract all request parameters and their values from request object | |
| * | |
| * @param request {@link HttpServletRequest} | |
| * @return all request parameters in the form: | |
| * param-name 1 | |
| * param-value | |
| * param-name 2 | |
| * param-value | |
| * param-value (in case of multiple values) | |
| */ | |
| private String getAllRequestParams(HttpServletRequest request) | |
| { | |
| Map map = request.getParameterMap(); | |
| StringBuilder sb = new StringBuilder("\nREQUEST PARAMETERS\n"); | |
| for (Iterator it = map.keySet().iterator(); it.hasNext();) | |
| { | |
| String pn = (String)it.next(); | |
| sb.append(pn).append("\n"); | |
| String[] pvs = (String[]) map.get(pn); | |
| for (int i = 0; i < pvs.length; i++) { | |
| String pv = pvs[i]; | |
| sb.append("\t").append(pv).append("\n"); | |
| } | |
| } | |
| return sb.toString(); | |
| } | |
| public Logger getLogger() { | |
| return logger; | |
| } | |
| public void setLogger(Logger logger) { | |
| this.logger = logger; | |
| } | |
| public IpnConfig getIpnConfig() { | |
| return ipnConfig; | |
| } | |
| public void setIpnConfig(IpnConfig ipnConfig) { | |
| this.ipnConfig = ipnConfig; | |
| } | |
| public IpnInfoService getIpnInfoService() { | |
| return ipnInfoService; | |
| } | |
| public void setIpnInfoService(IpnInfoService ipnInfoService) { | |
| this.ipnInfoService = ipnInfoService; | |
| } | |
| } |
As for ‘IpnConfig.java’:
- ‘ipnUrl’ should be:
- For Production/Live - https://www.paypal.com/cgi-bin/webscr
- For Sandbox/Testing - https://www.sandbox.paypal.com/cgi-bin/webscr
- ‘receiverEmail’ should be the Paypal Account Email
- ‘paymentAmount’ should be the ‘Price’ you setup while defining Paypal Button above.
- ‘paymentCurrency’ should be the ‘Currency’ you mention while defining the Paypal Button above.
Now,
humayun,
ReplyDeleteThis is good affords. Nice one.
Rehan Rana