Update XML element text with PHP - php

Question

I'm trying to update XML element text based upon a form submission. It is a userdatabase and im using the user's password as a reference to update their user id. The passwords all all unique so I thought it would be an easy element to reference. However whenever I attempt to edit a UID it fails and sends me to my error page I created if the function fails. Im not sure where I went wrong any assistance would be great.
Update UID Function
function updateUID($pass, $file, $new)
{
$xml = new DOMDocument();
$xml->load($file);
$record = $xml->getElementsByTagName('UniqueLogin');
foreach ($record as $person) {
$password_id = $person->getElementsByTagName('Password')->item(0)->nodeValue;
//$person_name=$person->getElementsByTagName('name')->item(0)->nodeValue;
if ($password_id == $password) {
$id_matched = true;
$updated = $xml->createTextNode($new);
$person->parentNode->replaceChild($person, $updated);
break;
}
}
if ($id_matched == true) {
if ($xml->save($file)) {
return true;
}
}
}
Code that calls the function
session_start();
include_once "includes/functions.inc.php";
include_once "includes/jdbh.inc.php";
include_once "includes/dbh.inc.php";
include_once "includes/ftpconn2.inc.php";
$file = $_SESSION['fileNameXML'];
if (file_exists($file)) {
if (isset($_POST['submit'])) {
$pass = $_POST['id'];
//$uid = $_SESSION['userid'];
$new = $_POST['uid'];
//$entry = getUsername($jconn, $uid)." deleted a server ban for".$name;
//if (isset($_GET['confirm'])) {
if (updateUID($pass, $file, $new)) {
//createLogEntry($conn, $uid, $entry);
if (1 < 2) { //This is intentional to get around the $message varible below that is not required.
$message = $affectedRow . " records inserted";
try {
$ftp_connection = ftp_connect($ftp_server);
if (false === $ftp_connection) {
throw new Exception("Unable to connect");
}
$loggedIn = ftp_login($ftp_connection, $ftp_user, $ftp_password);
if (true === $loggedIn) {
//echo "Success!";
} else {
throw new Exception('unable to log in');
}
$local_file1 = "HostSecurity.xml";
$remote_file1 = "HostSecurity.xml";
if (ftp_put($ftp_connection, $local_file1, $remote_file1, FTP_BINARY)) {
//echo "Successfully written to $local_file\n";
} else {
echo "There was a problem";
}
ftp_close($ftp_connection);
header("location: ../serverPasswords.php");
}
catch (Exception $e) {
echo "Failure:" . $e->getMessage();
}
}
header("location: ../serverPasswords.php");
} else {
header("location: ../serverPasswords.php?e=UIDNPD");
}
} else {
echo "id missing";
}
} else {
echo "$file missing";
}
<Unique_Logins>
<UniqueLogin>
<UID>AA23GHRDS657FGGRSF126</UID>
<Password>iMs0Az2Zqh</Password>
</UniqueLogin>
<UniqueLogin>
<UID>AA23GSDGFHJKDS483FGGRSF126</UID>
<Password>Ab7wz77kM</Password>
</UniqueLogin>
</Unique_Logins>

Answer 1

I believe the issue was caused by the undeclared variable $password in the logic test and the fact that the function never returns an alternative value if things go wrong.
As per the comment regarding XPath - perhaps the following might be of interest.
<?php
$pass='xiMs0Az2Zqh';
$file='logins.xml';
$new='banana';
function updateUID( $pass=false, $file=false, $new=false ){
if( $pass & $file & $new ){
$dom = new DOMDocument();
$dom->load( $file );
# attempt to match the password with this XPath expression
$expr=sprintf( '//Unique_Logins/UniqueLogin/Password[ contains(.,"%s") ]', $pass );
$xp=new DOMXPath( $dom );
$col=$xp->query( $expr );
# We have a match, change the UID ( & return a Truthy value )
if( $col && $col->length===1 ){
$xp->query('UID', $col->item(0)->parentNode )->item(0)->nodeValue=$new;
return $dom->save( $file );
}
}
# otherwise return false
return false;
}
$res=updateUID( $pass, $file, $new );
if( $res ){
echo 'excellent';
}else{
echo 'bogus';
}
?>

Answer 2

I'm still not clear on exactly what's wrong, but if I understand you correctly, try making these changes in your code and see if it works:
#just some dummy values
$oldPass = "Ab7wz77kM";
$newUid = "whatever";
$record = $xml->getElementsByTagName('UniqueLogin');
foreach ($record as $person) {
$password_id = $person->getElementsByTagName('Password');
$user_id = $person->getElementsByTagName('UID');
if ($password_id[0]->nodeValue == $oldPass) {
$user_id[0]->nodeValue = $newUid;
}
}