I'm glad there are similar questions, but I can't get any solution to work with my (inherited) code, so any help you can provide would be greatly appreciated.
We use Sage Pay / Opayo payment gateway via form integration.
Upon completion/failure, the customer will be redirected to a URL on our website with an encrypted _GET string.
After decryption, call the getToken function ( $values = getToken($Decoded); ) to get the values from the array.
However, not all tags are always populated and I suspect these null values may be the source of the problem.
This code runs fine on PHP 7.1, but throws an exception on PHP 8.1:
[2023-05-03 15:12:15 Europe/London] PHP fatal error: Uncaught error: Trying to assign property 'start' on null in /home/sitename/public_html/ch_functions.php:166 Stack trace: #0 /home/sitename/public_html/not_completed.php(32): getToken('VendorTxCode=AP...') #1 {Main} Throwing in /home/sitename/public_html/ch_functions.php line 166
The code is, what fails on $resultArray[$i]->start = $start; is:
function getToken($thisString) {
// List the possible tokens
$Tokens = array("Status","StatusDetail","VendorTxCode","VPSTxId","TxAuthNo","Amount","AVSCV2","AddressResult","PostCodeResult","CV2Result","GiftAid","3DSecureStatus","CAVV", "AddressStatus", "PayerStatus", "CardType", "Last4Digits","BankAuthCode","DeclineCode");
// Initialise arrays
$output = array();
$resultArray = array();
// Get the next token in the sequence
for ($i = count($Tokens)-1; $i >= 0 ; $i--){
// Find the position in the string
$start = strpos($thisString, $Tokens[$i]);
// If it's present
if ($start !== false){
// Record position and token name
$resultArray[$i]->start = $start;
$resultArray[$i]->token = $Tokens[$i];
}
}
// Sort in order of position
sort($resultArray);
// Go through the result array, getting the token values
for ($i = 0; $i<count($resultArray); $i++){
// Get the start point of the value
$valueStart = $resultArray[$i]->start + strlen($resultArray[$i]->token) + 1;
// Get the length of the value
if ($i==(count($resultArray)-1)) {
$output[$resultArray[$i]->token] = substr($thisString, $valueStart);
} else {
$valueLength = $resultArray[$i+1]->start - $resultArray[$i]->start - strlen($resultArray[$i]->token) - 2;
$output[$resultArray[$i]->token] = substr($thisString, $valueStart, $valueLength);
}
}
// Return the ouput array
return $output;
} 
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You referenced
$resultArray[$i]as an object, but the array is empty, so there is no object to reference. In PHP 7.4 and earlier versions you can do the following:PHP will dynamically create a
stdClassobject at$x[0]and then dynamically create the foo property, but will issue a warning:You are currently suppressing or ignoring this warning. In PHP 8.0, this now generates a fatal error. So just create an empty object before trying to set its value:
if ($start !== false) { $resultArray[$i] = new stdClass(); $resultArray[$i]->start = $start; $resultArray[$i]->token = $Tokens[$i]; }or:
if ($start !== false) { $resultArray[$i] = (object) [ 'start' => $start, 'token' => $Tokens[$i], ]; }