Parse through XML childs - php

Question

i have the following xml:
<?xml version="1.0" standalone="yes"?>
<Products>
<Product>
<name>Milk</name>
<price>1.4</price>
<productinfos>
<category1 value="somecategory1"/>
<category2 value="somecategory2"/>
<category3 value="somecategory3"/>
</productinfos>
</Product>
</Products>
how can i make sure that productinfos category1, category2 or category3 do exist and are not an empty string? And how does the loop look like if i want the following output:
//output
Cat1: somecategory1
Cat3: somecategory3
Cat2: somecategory2
because sometimes the xml i parse looks different:
<?xml version="1.0" standalone="yes"?>
<Products>
<Product>
<name>Milk</name>
<price>1.4</price>
<productinfos>
<category1 value=""/>
<category3 value="somecategory"/>
</productinfos>
</Product>
</Products>
in the above example, how can i check if category2 exists?
tia for your efforts!

Answer 1

You're looking for the SimpleXMLElement::children() method.
https://secure.php.net/manual/en/simplexmlelement.children.php
$xml = new SimpleXMLElement(<<<XML
<?xml version="1.0" standalone="yes"?>
<Products>
<Product>
<name>Milk</name>
<price>1.4</price>
<productinfos>
<category1 value="somecategory1"/>
<category2 value="somecategory2"/>
<category3 value="somecategory3"/>
</productinfos>
</Product>
</Products>
XML
);
// $xml is a SimpleXMLElement of <Products>
foreach ($xml->children() as $product) {
if ($product->getName() != 'Product') {
// ignore <Products><Cow> or whatever, if you care
continue;
}
// start out assuming that everything is missing
$missing_tags = array(
'category1' => true,
'category2' => true,
'category3' => true,
);
// iterate through child tags of <productinfos>
foreach ($product->productinfos->children() as $productinfo) {
// element name is accessed using the getName() method, and
// XML attributes can be accessed like an array
if (isset($missing_tags[$productinfo->getName()]) &&
!empty($productinfo['value'])) {
$missing_tags[$productinfo->getName()] = false;
echo $productinfo->getName() . ": " . $productinfo['value'] . "\n";
}
}
// array_filter with one argument filters out any values that eval to false
if (array_filter($missing_tags)) {
echo "Missing tags: " . implode(", ", array_keys($missing_tags)) . "\n";
}
}
The SimpleXML extension is rather less intuitive than the name would suggest, but it's about as simple as you can get with XML...