Paypal IPN Validation in PHP

Question: How to IPN? How to set IPN in Paypal?
http://www.web-technology-experts-notes.in/2016/03/instant-payment-notification-paypal.html


Question: Why we need to validate the IPN?
To make sure, all data sent in our server is from Paypal.


Question: What are benefits of validating the IPN?

1. Protect our transaction from SPAM OR robots OR from hackers.
2. Protect from dmmmy entires in our database.
3. If protection is ON, We will always sure for transaction record in database.

Question: What does paypal do with valiation?
It will validate all the data, sent to paypal.


Question: What is name of parameter which is send to paypal for validation?
cmd.
For Example:

cmd=_notify-validate

Question: What does paypal return if validation failed?
INVALID


Question: How does paypal return, if validation passed?
VERIFIED


Question: How to validate IPN Response in Sandbox Mode?

$ipnData=$_POST;
$ipnData['cmd']='_notify-validate';
$verify= file_get_contents('https://www.sandbox.paypal.com/cgi-bin/webscr', false, stream_context_create(array(
            'http' => array(
                'header'  => "Content-type: application/x-www-form-urlencoded\r\nUser-Agent: MyAPP 1.0\r\n",
                'method'  => 'POST',
                'content' => http_build_query($ipnData)
            )
        )));  
if($verify=='VERIFIED'){
/** Your data is valid and it is return from paypal */

}

Question: How to validate Paypal IPN Response in LIVE Mode ?

$ipnData=$_POST;
$ipnData['cmd']='_notify-validate';
$verify= file_get_contents('https://www.paypal.com/cgi-bin/webscr', false, stream_context_create(array(
            'http' => array(
                'header'  => "Content-type: application/x-www-form-urlencoded\r\nUser-Agent: MyAPP 1.0\r\n",
                'method'  => 'POST',
                'content' => http_build_query($ipnData)
            )
        )));  
if($verify=='VERIFIED'){
/** Your data is valid and it is return from paypal */

}

Question: How to validate IPN Validate with curl?

$ipnData=$_POST;
$ipnData['cmd']='_notify-validate';

$validateURL='https://www.paypal.com/cgi-bin/webscr';//for paypal
//$validateURL='https://www.sandbox.paypal.com/cgi-bin/webscr'; //for sandbox paypal
   
$ch = curl_init($validateURL);
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_1);
curl_setopt($ch, CURLOPT_POST, 1);
curl_setopt($ch, CURLOPT_RETURNTRANSFER,1);
curl_setopt($ch, CURLOPT_POSTFIELDS, http_build_query($ipnData));
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 1);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 2);
curl_setopt($ch, CURLOPT_FORBID_REUSE, 1);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Connection: Close'));
if ( !($verify = curl_exec($ch)) ) {          
 curl_close($ch);
 die('Some Error');
}
curl_close($ch); 
var_dump($verify );//IF VERIFIED, then validate

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Javascript Questions And Answers for Fresher and Experienced

Question: How to pass multiple parameter in setTimeout function?

function myFunctionName(var1,var2){
    console.log('called after 2 sec of page load '+var1+' '+var2);
}
setTimeout(myFunctionName,2000,'value1','value2');

Question: How to enumerate the properties of js objects?

var myObject = {name1: 'Value1',name2: 'Value2'};
//console.log(myObject); //It will print all the values

for (var name in myObject) {
  //console.log(name+'=>'+myObject[name]);
  }

Question: How to measure the execution time of javascript script?

var startTime = new Date().getTime();
/*
Write here you script
*/
for(i=1;i<=500000; i++){
}
var endTime = new Date().getTime();

var time = endTime - startTime;
console.log('Execution time in Milli Seconds: ' + time);
console.log('Execution time in Seconds: ' + time/1000);

Question: How to listen (Do some changes) the window.location.hash change?

$(window).on('hashchange', function() {  
  callNewFunction(window.location.href)  
});
function callNewFunction(url){
    console.log('Hash URL is called');
}

After appling above code, whenever you add/update the hash value, callNewFunction will called automatically.

hashchange event is HTML5 feature and supported by all modern browsers and support is added in following browser.

1. Internet Explorer 8
2. Firefox 3.6
3. Chrome 5
4. Safari 5
5. Opera 10.6

Question: How to add class in an element?
HTML Part

<div id="myDivId">
</div>

javaScript Part

var d = document.getElementById("myDivId");
d.className += " newClass";

Question: How to get the list of classes for an element?

d = document.getElementById("myDivId");
console.log(d.className);

Question: Can we compare two javaScript objects?
Yes, We can compare two javascript objects. See Following examples.

var myObject1 = {name1: 'Value1',name2: 'Value2'};
var myObject2 = {name1: 'Value111',name2: 'Value222'};
if(JSON.stringify(myObject1) === JSON.stringify(myObject2)){
 console.log("Both object are same");
}else{
console.log("Both object are different");
} 

Question: What is difference between Array(3) and Array('3') in javascript?
new Array(3), means declare the 3 elements and each have value "undefined". new Array('3'), means declare the 1 element and have value 3.

console.log(new Array(3)); // [undefined, undefined, undefined]
console.log(new Array('3')); // ["3"]

Question: How to get browser URL for all browser?

console.log(window.location.href);

Question: How to remove an element(string OR object ) from javascript Array/Object?

var myObject = {name1: 'Value1',name2: 'Value2'};
delete myObject['name1']
console.log(myObject);

Question: What does jQuery.fn mean?
jQuery.fn is just an prototype for defining the new functions.
fn is an alias to the prototype property.
For Example,

$.fn.newFunctionName = function(val){
console.log('something '+val); //something Test Value
};
$.fn.newFunctionName('Test Value');

Question: How to remove an empty elements from an Array?

var simpleArray = [1,3,,3,null,,0,,undefined,4,,6,,];
var cleanArray = simpleArray.filter(function(n){ return n != undefined }); 
console.log(cleanArray);

Question: How to add 5 days in JavaScript?

var result = new Date();
result.setDate(result.getDate() + 5);
console.log(result);

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