Xml Dom Php

Nibinaear

I'm trying to write some code to get a description from an XML document and print it out. Basically you pass in a city code like NCL and it gives you back Newcastle for example. Here is an example of my XML:

<locations>
  <location>
    <code>ABZ</code>
    <description>Aberdeen</description>
  </location> 

  ...

But if you look at the xpath string in the following code, it does refer to the right place. What am I doing wrong? I can still refer to the rest of the dom can't I if I use [] in my xpath string?


<?php

function getDesc($code)
{
  $answer = "";

  $thedoc = new DOMDocument;

  // Ignore whitespace between nodes (default: true)
  $thedoc->preserveWhiteSpace = false;

  // Load the XML data source
  $thedoc->Load('flight.xml');

  // Create a DOMXpath instance based on the
  // DOMDocument object
  $xpath = new DOMXPath($thedoc);

  $qry = "/locations/location/code[. = \"".$code."\"]";

  echo $qry;

  // Execute the query and return a DOMNodeList
  $entries = $xpath->query($qry);

  foreach($entries as $entry)
  {
    $answer = $entry->parentNode->firstChild->nextSibling->nodeValue;
  }

  echo "<p />Answer ".$answer."<p />";

  return $answer;
}//end of function

echo getDesc("NCL");

?>

Weedpacket

Not sure what you mean - certainly there's nothing about not being allowed to use XPath predicates in XPath strings.

I try ABZ the XPath expression is reported as
/locations/location/code[. = "ABZ"]
and the returned result is Aberdeen. Is this not desired behaviour? (You don't say what it's doing that's wrong).

But I do note one point that might (depending on what else your code does) simplify what you have.

$qry = "/locations/location/description[../code = \"".$code."\"]";

  echo $qry;

  // Execute the query
  $answer = $xpath->query($qry)->item(0)->nodeValue; // I'm assuming that there'll only be one node in the returned list.
  echo "<p>Answer $answer</p>";

Nibinaear

The problem is that I'm not getting any results back, I don't know why this is. Answer is not reporting any information.

Normally this happens when you don't reference the right node, but:

$answer = $entry->parentNode->firstChild->nextSibling->nodeValue;

The current node is code, parent is location, first child is code again, next sibling is description. Isn't that right?

Weedpacket

Well, like I said, I'm getting what I expected.

/locations/location/code[. = "ABZ"]<p />Answer Aberdeen<p />

And all I did was copy-and-paste what you posted. (Tell a lie; I completed the XML fragment and added a second location.)

What debugging have you done?

Nibinaear

It's okay, it's fixed now, thanks for the help.

Daniel