SimpleXML namespaced attributes and value is empty?

Question

I have the following type of XML structure:

<catalog xmlns="http://www.namespace.com">
    <product product-id="test-product">
        <page-attributes>
            <page-title xml:lang="en">test</page-title>
            <page-title xml:lang="de">test2</page-title>
        </page-attributes>
    </product>
</catalog>

I used the following to fetch the product and it's page-title elements:

$xml->registerXPathNamespace('ns', $xml->getNamespaces()[""]);
$xpath = '//ns:product[@product-id="test-product"]';
$product = $xml->xpath($xpath)[0];

foreach ($product->{'page-attributes'}->{'page-title'} as $title) {
    var_dump($title);
    var_dump($title->{"@attributes"});
    var_dump($title->attributes());
}

But I just get:

object(SimpleXMLElement)#4 (0) {
}
object(SimpleXMLElement)#6 (0) {
}
object(SimpleXMLElement)#6 (0) {
}
object(SimpleXMLElement)#6 (0) {
}
object(SimpleXMLElement)#4 (0) {
}
object(SimpleXMLElement)#4 (0) {
}

How do I get the values of the page-title elements (test,test2)? Also how do I get the attributes? The attributes have xml: in front of them. Does that mean just the attributes are in their own namespace?

Cast them to a string (which is how you always have to get them from SimpleXML): `echo (string)$title;` inside the `foreach` loop... Everything else you have should work. `SimpleXMLElement` implements `__toString()`, but `var_dump()` won't respect that and it will always just look like you're getting more `SimpleXMLElement` objects back. — Michael Berkowski, Jan 28 '15 at 16:27

hek2mgl · Accepted Answer · 2015-01-28T16:53:08.210

3

Two things are wrong with your code:

As @MichaelBerkowski mentioned, you need to convert an SimpleXMLElement to string if you attempt to retrieve it's value.
You need to specify the namespace xml: if you attempt to retrieve the values of the lang attributes.

Your code should look like this:

$xml->registerXPathNamespace('ns', $xml->getNamespaces()[""]);

$xpath = '//ns:product[@product-id="test-product"]';
$product = $xml->xpath($xpath)[0];

foreach ($product->{'page-attributes'}->{'page-title'} as $title) {
    var_dump((string) $title);
    var_dump((string) $title->attributes('xml', TRUE)['lang']);
}

Output:

string(4) "test"
string(2) "en"
string(5) "test2"
string(2) "de"

About the string conversion. Note that if you would attempt to do the following:

echo "Title: $title";

you won't have to explicitly convert to string since a SimpleXMLElement supports the __toString() method and PHP will convert it automatically to a string - in a such a string context.

var_dump() cannot assume a string context and therefore it outputs the "real" type of the variable: SimpleXMLElement.

edited Jan 28 '15 at 16:53

answered Jan 28 '15 at 16:47

hek2mgl

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Ah thank you that makes sense now. When do I use the `{"@attributes"}` nomenclature? I've seen that and I'm not sure when that applies. – Jake Wilson Jan 28 '15 at 17:06
PHP allows to access object properties like `$obj->{"PROPERTYNAME"}`. (true for every kind of object). The `SimpleXMLElement` has a property (literally) called `@attributes`, which is again a `SimpleXMLElement`. – hek2mgl Jan 28 '15 at 17:16
Can you not reference namespaced attributes via `@attributes`? – Jake Wilson Jan 28 '15 at 18:40
I don't think that this is possible. – hek2mgl Jan 28 '15 at 18:46

SimpleXML namespaced attributes and value is empty?

1 Answers1