Invalid transaction when using PAYPAL API - php

Question

I am using PAYPAL API.
I success calling the setExpressCheckout (after calling this method I got ACK=Success) and therefore get a full link that I can proceed with.
After getting the full link (https://www.paypal.com/cgi-bin/webscr?cmd=_flow&SESSION=[SESSION_TOKEN]), the full link represent a page, that includes error.
The error:
This transaction is invalid. Please return to the recipient's website to complete your transaction using their regular checkout flow.
Return to merchant
At this time, we are unable to process your request. Please return to and try another option
Here is my Code:
<?php
/*.
require_module 'standard';
require_module 'standard_reflection';
require_module 'spl';
require_module 'mysqli';
require_module 'hash';
require_module 'session';
require_module 'streams';
.*/
//turn php errors on
//ini_set('track_errors', true);
require_once __DIR__ . "/stdlib/all.php";
require_once __DIR__ . "/SqlManager.php";
/*. array .*/ $body_data = null;
$body_data_txt = "";
/*. string .*/ $htmlpage = "";
/*. array .*/ $keyAr = array();
/*. array .*/ $tokenAr = array();
$response = "";
/*. SqlManager .*/ $sqlm = null;
session_start();
$url = trim('https://api-3t.paypal.com/nvp');
$urlRun = trim('https://www.paypal.com/cgi-bin/webscr');
$body_data = array( 'USER' => *****",
'PWD' => "******",
'SIGNATURE' => "*****",
'VERSION' => "95.0",
'PAYMENTREQUEST_0_PAYMENTACTION' => "Sale",
'PAYMENTREQUEST_0_AMT' => (string)$_SESSION["AMOUNT"],
'PAYMENTREQUEST_0_CURRENCYCODE' => 'USD',
'RETURNURL' => "******",
'CANCELURL' => "******",
'METHOD' => "SetExpressCheckout"
);
$body_data_txt = http_build_query($body_data, '', chr(38));
try
{
$sqlm = new SqlManager(true);
//create request and add headers
$params = array(
'http' => array(
'protocol_version' => "1.1",
'method' => "POST",
'header' => "".
"Connection: close\r\n".
"Content-Length: ".strlen($body_data_txt)."\r\n".
"Content-type: "."application/x-www-form-urlencoded"."\r\n",
'content' => $body_data_txt
));
//create stream context
$ctx = stream_context_create($params);
//open the stream and send request
try {
$fp = fopen($url, 'r', false, $ctx);
} catch(ErrorException $e) {
throw new ErrorException("cannot open url" . $url . " error:" . $e->getMessage());
}
//get response
$response = (string)stream_get_contents($fp);
//check to see if stream is open
if ($response === "") {
throw new Exception("php error message = " . "$php_errormsg");
}
//close the stream
fclose($fp);
$key = explode("&", $response);
$keyAr = array();
foreach ($key as $i => $value) {
$tmpAr = explode("=", $value);
if(sizeof($tmpAr) > 1) {
$keyAr[$tmpAr[0]] = $tmpAr[1];
}
}
if (substr($response, 0, 1) === "<") {
echo $response;
} else {
// Extract the response details.
if((0 == sizeof($keyAr)) || !array_key_exists('ACK', $keyAr) || (string)$keyAr["ACK"] !== "Success") {
if (array_key_exists('L_ERRORCODE0', $keyAr) && array_key_exists('L_LONGMESSAGE0', $keyAr)) {
echo cast("string", htmlspecialchars(urldecode((string)$keyAr["L_ERRORCODE0"]))) . ',' .
cast("string", htmlspecialchars(urldecode((string)$keyAr["L_LONGMESSAGE0"])));
} else {
echo "Unkown server response!";
}
} else {
// ********************************************
$htmlpage = $urlRun . "?cmd=_express-checkout&". "TOKEN=" . (string)$keyAr["TOKEN"]; // ******************* IS THIS LINE OK????
// ********************************************
echo "ok," . $htmlpage;
}
}
}
catch(Exception $e)
{
echo 'Message: ||' .cast("string", str_replace('"', '\\"', $e->getMessage())).'||';
}
?>
the $htmlpage got the full link (see the line with the asterisks remark 'IS THIS LINE OK')
My account is business account.
What may be the cause for the problem?
Seem kind of configuration problem - are there any setups I shall check?
Thanks :)

Answer 1

The problem is that I have opened the paypal page with 'TOKEN=', and I should open by 'token='
(capitalized letter matter).
The line:
$htmlpage = $urlRun . "?cmd=_express-checkout&". "TOKEN=" . (string)$keyAr["TOKEN"];
should be:
$htmlpage = $urlRun . "?cmd=_express-checkout&". "token=" . (string)$keyAr["TOKEN"];
Thanks, anyway :)