looks like we got no XML document - nice message, but why is it so? 🤔

[trailsnail]

What is it about?

We retrieve data via a SOAP api, a list of many offers.
These offers are created and maintained in the customer's ERP system. Employees sometimes copy text from Word or a PDF into the text fields of a offer. Sometimes special characters are inserted.

When decoding the request response in the ExtSoapDecoder::decode(), the error looks like we got no XML document occurs. The entire process aborts. The error-free offers cannot be processed due to an incorrect offer.

Unfortunately, it is not possible to retrieve each offer individually in order to bypass the incorrect one.

What can we do?

Debugging is currently the order of the day, narrowing down the period from when the error occurs and which offers could match it. Then retrieve the offer explicitly via Postman or debugging in the code, copy the response for decoding into the IDE or examine it with text editors to find the needle in the haystack that makes decoding impossible.

Is there another way?

It would be helpful to have an error output that provides us with information about where the error is in the data or even what exactly is causing the error.
Do you also struggle with such challenges or have you already found a solution? We would be delighted to hear your ideas and suggestions.

Kind regards

[veewee]

Hello,

The exception is coming from PHP's SoapClient and means it is unable to parse the provided XML response.

 is an invalid character in XML. The best way to overcome this error is to add a HTTP plugin/Middleware that makes sure the XML is parsable by for example cleaning up this and any other unsupported character you encounter before they get decoded by the SoapClient.

https://3v4l.org/PkH7j

$doc = new DOMDocument();
$doc->loadXML('<test>wor&#x2;ld</test>');

echo($doc->documentElement->nodeValue);

Warning: DOMDocument::loadXML(): xmlParseCharRef: invalid xmlChar value 2 in Entity,

[trailsnail]

Thank you. We will have a look into this 👀

[trailsnail]

Thanks again for the tip ❤️

We now parse the response before Client decoding with DOMDocument via middleware.
If an error occurs, various regexes are used to determine details from the XML string.
Starting from the error position, we take a substring and determine the XML entities with their content in order to enrich the notification with helpful details.

The XMLReader was unfortunately not an option, as it already removes invalid entities from the response during initialization - I was surprised that the XML was generally valid when I tried it.

// Middleware
public function afterResponse(ResponseInterface $response): ResponseInterface
{
    try {
        $this->parseXmlPreflight($response->getBody()->getContents());
    } catch (Throwable $e) {
        // do nothing atm
    }

    return parent::afterResponse($response);
}

private function parseXmlPreflight(string $xmlString): void
{
	$dom = new DOMDocument();
	libxml_use_internal_errors(true); // Enable error handling
	$dom->loadXML($xmlString, LIBXML_NOERROR);

	$errors = libxml_get_errors();
	if ($errors === []) {
		return;
	}

	$message = new MattermostMessage('Fehler bei der Verarbeitung von XML-Daten', ':rotating_light:', true);

	$this->enrichUserRequestDetails($message);

	foreach($errors as $error) {
		$this->collectErrorDetails($message, $error, $xmlString); // Try to extract details from XML to enrich the notification
	}

	$message->notifyPhilippTeamInternal();
}

[veewee]

That's some sweet error handling! 😮 Nice.