Get an item from xml by path.

xml_get.php

<?php

// https://phpsandbox.io/n/steep-union-wnew-ndjxv

function xml_get(
    SimpleXMLElement|string $xml, 
    string $path, 
    mixed $default = null
): mixed
{
    if(! $xml instanceof SimpleXMLElement) {
        $xml = simplexml_load_string($xml);
    }

    $value = $xml->xpath($path)[0] ?? null;

    if(! $value) {
        return $default;
    }

    $value = $value->count() > 1
        ? json_decode(json_encode($value), true)
        : (string) $value;

    return $value ?? $default;
}

$xml = <<<XML
<ns0:sptransferrequest xmlns:ns0="http://www.ericsson.com/em/emm/serviceprovider/v1_0/backend">
    <sendingfri>FRI:test.sp/USER</sendingfri>
    <receivingfri>FRI:256782123123/MSISDN</receivingfri>
    <amount>
        <amount>1000.00</amount>
        <currency>UGX</currency>
    </amount>
    <providertransactionid>20221005_002</providertransactionid>
    <sendernote>To 256782123123</sendernote>
    <receivermessage>From Tester</receivermessage>
    <referenceid>687e2e7e-f74a-44dd-b1ab-a516340f1565</referenceid>
</ns0:sptransferrequest>
XML;

// // $xml = new SimpleXMLElement($xml);

// $value = xml_get($xml, 'transactionid'); // null

// $value = xml_get($xml, 'transactionid', '10035424'); // 10035424

// $value = xml_get($xml, 'sendingfri'); // FRI:test.sp/USER

// $value = xml_get($xml, 'amount'); // ['amount' => '1000.00', 'currency' => 'UGX']

$value = xml_get($xml, 'amount/currency'); // EUR

print_r($value);