XPath not returning results on Google App Engine for PHP

Question

I'm having an issue using XPath on the Google App Engine for PHP.

So I have the following code:

function getDataXpath($url_str, $xpath_exp_str)
{
    $doc = new DOMDocument();
    libxml_use_internal_errors(true);
    $doc->loadHTMLFile($url_str);
    libxml_use_internal_errors(false);

    $xpath = new DOMXpath($doc);
    $elements = $xpath->query("".$xpath_exp_str."");

    if (!is_null($elements)) {
        return $elements;
    }

    return false;
}

And then I simply run it like this to get the nodes:

getDataXpath($url_str, $xpath_exp_str);

So on my local PHP install (v 5.5.19), when I run the following:

$url_str = 'http://www.alexa.com/topsites/category;0/Top/Shopping';
$xpath_exp_str = "//ul/li[@class='site-listing']/div/p/a";
$xpath_data = getDataXpath($url_str, $xpath_exp_str);
print_r($xpath_data);

I get the following result:

DOMNodeList Object ( [length] => 25 ); 

and this is correct.

However, when I run the same code on Google App Engine for PHP (v 5.5.26), I get the following:

DOMNodeList Object ( [length] => 0 ); 

Has anyone had this issue, and how did you fix it?

Answer 1

So it appears that Amazon might be blocking programmatic access to the Alexa TopSites pages. I'm actually subscribed to their new API , but it doesn't allow you to categorize responses (eg top e-commerce sites) like you can on the website, which is why I'm resorting to XPath.

I tried the same script on some other URLs and I didn't have any issues.

Anyway, it works when I run it locally (in browser and command-line), so I'll just have to skip Google App Engine for now. It's a broken workflow, especially since this was part of a much bigger automation effort, but it's out of my hands at this point.