You've been fooled (and had me fooled) by the oldest trick in the SimpleXML book: SimpleXML doesn't parse the whole document into a PHP object, it presents a PHP API to an internal structure. Functions like var_dump
can't see this structure, so don't always give a useful idea of what's in the object.
The reason it looks "empty" is that it is listing the children of the root element which are in the default namespace - but there aren't any, they're all in the "soapenv:" namespace.
To access namespaced elements, you need to use the children()
method, passing in the full namespace name (recommended) or its local prefix (simpler, but could be broken by changes in the way the file is generated the other end). To switch back to the "default namespace", use ->children(null)
.
So you could get the ID
attribute of the first stationV2
element like this (live demo):
// Define constant for the namespace names, rather than relying on the prefix the remote service uses remaining stable
define('NS_SOAP', 'http://schemas.xmlsoap.org/soap/envelope/');
// Download the XML
$rawxml = file_get_contents("http://opendap.co-ops.nos.noaa.gov/axis/webservices/activestations/response.jsp?v=2&format=xml&Submit=Submit");
// Parse it
$ob = simplexml_load_string($rawxml);
// Use it!
echo $ob->children(NS_SOAP)->Body->children(null)->ActiveStationsV2->stationsV2->stationV2[0]['ID'];
I've written some debugging functions to use with SimpleXML which should be much less misleading than var_dump
etc. Here's a live demo with your code and simplexml_dump
.