Debugging ipn.php when using paypal sandbox ipn simulator - php

Question

How do I debug the ipn.php file when using the paypal sandbox ipn simulator tool?
The code looks like this:
// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';
foreach($_POST as $key = > $value) {
$value = urlencode(stripslashes($value));
$req. = "&$key=$value";
}
// post back to PayPal system to validate
$header = "POST /cgi-bin/webscr HTTP/1.0\r\n";
$header. = "Content-Type: application/x-www-form-urlencoded\r\n";
$header. = "Content-Length: ".strlen($req)."\r\n\r\n";
$fp = fsockopen('ssl://www.sandbox.paypal.com', 443, $errno, $errstr, 30);
if (!$fp) {
// HTTP ERROR
} else {
fputs($fp, $header.$req);
while (!feof($fp)) {
$res = fgets($fp, 1024);
if (strcmp($res, "VERIFIED") == 0) {
$DBH = new PDO("mysql:host=localhost;dbname=db", "user", "pass");
$DBH - > setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$STH = $DBH - > prepare("update table2 set status = :status where tracking_id = :tracking_id");
$status = 1;
parse_str($req, $data);
$STH - > bindParam(':status', $status, PDO::PARAM_INT, 1);
$STH - > bindParam(':tracking_id', 'id_goes_here', PDO::PARAM_STR, 50);
$STH - > execute();
$DBH = null;
} else if (strcmp($res, "INVALID") == 0) {
// do something else
}
}
fclose($fp);
}
I normally use netbeans debug facility to debug, but how do I debug using the sandbox simulator? When I click send ipn from the sandbox ipn simulator, I get a message in the sandbox saying IPN successfully sent., but when I then go into my database to check the status, it's still 0.

Answer 1

Maybe problem is in parameter binding
$STH - > bindParam(':tracking_id', 'id_goes_here', PDO::PARAM_STR, 50);
if table 'table2' do not contain row with tracking_id = 'id_goes_here' update action will fail.
Try this
<?php
$testMode = false;
$url = 'https://www.paypal.com/cgi-bin/webscr';
if ($testMode === true)
$url = 'https://www.sandbox.paypal.com/cgi-bin/webscr';
$ipnResponse = ''; // holds the IPN response from paypal
$ipnData = array(); // array will contain the POST values for IPN
$urlParsed = parse_url($url);
$req = 'cmd=_notify-validate'; // Add 'cmd' to req (ipn command)
// Read the post from PayPal system and add them to req
foreach ($_POST as $key => $value) {
$ipnData["$key"] = $value;
$value = urlencode(stripslashes($value));
$req .= "&" . $key . "=" . $value;
}
// Open the connection to paypal
$fp = fsockopen($urlParsed['host'], "80", $errno, $errstr, 30);
// If could open the connection and check response
if ($fp) {
fputs($fp, "POST " . $urlParsed['path'] . " HTTP/1.1\r\n");
fputs($fp, "Host: " . $urlParsed['host'] . "\r\n");
fputs($fp, "Content-type: application/x-www-form-urlencoded\r\n");
fputs($fp, "Content-length: " . strlen($req) . "\r\n");
fputs($fp, "Connection: close\r\n\r\n");
fputs($fp, $req . "\r\n\r\n");
// Loop through the response from the server and append to variable
while (!feof($fp)) {
$ipnResponse .= fgets($fp, 1024);
}
fclose($fp);
// Valid IPN transaction.
if (preg_match('/^VERIFIED/', $ipnResponse)) {
// Some action on IPN validation - update payment status etc
die("OK. IPN Validation: Success");
}
// Invalid IPN transaction
else {
// Some action on IPN validation - update payment status etc
die("ERROR. IPN Validation: Failed");
}
}
// Else no connection, so maybe wrong url or other reasons, you can do another call later
else {
die("ERROR. IPN Connection: fsockopen error");
}
?>

Answer 2

In general when I want to debug a script that doesn't provide direct output in the browser, I call a simple logging function throughout the script to output variable values or help determine where errors are occurring.
When I have no idea where the script is dying, I write a line to a log file after each significant line of code. After running the script and then checking the log file I can see exactly which line caused the script to die, a very simplified example is below. Of course after everything is running smoothly all of the logging should be removed.
public function logToFile($msg){
$file = 'log.txt';
$current = file_get_contents($file);
$current .= $msg . "\n";
file_put_contents($file, $current);
}
public function doOtherStuff(){
foreach ($_POST as $key => $value) {
$ipnData["$key"] = $value;
$value = urlencode(stripslashes($value));
$req .= "&" . $key . "=" . $value;
}
logToFile("1");
$fp = fsockopen($urlParsed['host'], "80", $errno, $errstr, 30);
logToFile("2");
if ($fp) {
logToFile("3");
fputs($fp, "POST " . $urlParsed['path'] . " HTTP/1.1\r\n");
logToFile("4");
fputs($fp, "Host: " . $urlParsed['host'] . "\r\n");
logToFile("5");
fputs($fp, "Content-type: application/x-www-form-urlencoded\r\n");
logToFile("6");
fputs($fp, "Content-length: " . strlen($req) . "\r\n");
logToFile("7");
fputs($fp, "Connection: close\r\n\r\n");
logToFile("8");
fputs($fp, $req . "\r\n\r\n");
logToFile("9");
while (!feof($fp)) {
logToFile("10");
$ipnResponse .= fgets($fp, 1024);
}
logToFile("11");
fclose($fp);
}
}