Use Xpath to find XML nodes with a specific child element

Question

I'm new to the world of XPath. I'm wanting to take an XML approach to powering my simple portfolio website instead of a database, which in this case would be superfluous as the only database element would be the projects themselves.

I've authored an XML file with the following structure:

<?xml version="1.0" encoding="UTF-8" ?>
<projects>
    <project>
        <title>A-Merchandise</title>
        <slug>a-merchandise</slug>
        <projectType>E-commerce</projectType>
        <launchDate>2007-08-01</launchDate>
    </project>
    ...

Now, I can parse this XML file fine with PHP for a listing overview, but how do I go about filtering projects with XPath? For example, how do I obtain all project nodes that has a child projectType node with the value e-commerce?

Normally, I would run a SQL query like:

SELECT * FROM `projects` WHERE `category` = 'e-commerce';

What would the XPath equivalent be? Is my XML file in the right structure to accomodate this filtering?

Any pointers would be great. Thanks in advance.

Answer 1

I believe you want this:

/projects/project[projectType="e-commerce"]

The [] filter selects all project elements under projects who have a projectType child with value "e-commerce"

I've also found this site to be very helpful for messing around with XPath and XSLT queries.

Further reading: http://www.w3schools.com/xpath/xpath_syntax.asp

Answer 2

considering your xml file name is foo.xml and is in same dir of bar.php which has content

$projects = simpleXMLElement('foo.xml',null,true);

$ecomProjects = $projects->xpath('project[projectType="E-commerce"]');

foreach($ecomProjects as $ecomProject)
{
echo $ecomProject; // or do whatever with it
}