Basic Use of the XPath class

If you need to use XML with PHP, look no further than the awesome <phpXML> class written by Michael P. Mehl, available from http://www.phpxml.org.

Why? Because it allows you to use the XPath expression syntax to access data. WAY easier than mucking around with, say the DOM.

An example of XPath’s functionality: say I have a CDATA tag called “ACCOUNT” which I wish to know the value of. In XPath, this is written “//ACCOUNT”. For an awesome tutorial on using XPAth, go to http://www.zvon.org/xxl/XPathTutorial/General/examples.html

Unfortunately, there is only limited information available on how to actually use <phpXML>, and none of it is particularly user-friendly. I searched high and wide for a simple tutorial, but to no avail. So here it is!

<?
include('xml.php');
$xml = new XML('test.xml');

// Evaluate the XPath expression.
 $zzz = $xml->evaluate('//ACCOUNT', '');

//aliter: to output all CDATA values in the XML
// $zzz = $xml->evaluate('//*', '');


// Now display the content of the XML file.

 foreach($zzz as $result)
 {
  $final = $xml->get_content($result);
  echo "Value:$final
";
 }
 $final=$xml->get_file($zzz);
?>

Here’s the example XML file (test.xml)

<?xml version="1.0"?>
<!--DTD-->
<!DOCTYPE TRANSDETAIL [
  <!ELEMENT TRANSDETAIL (RESPONSE)>
  <!ELEMENT RESPONSE (ACCOUNT, GOODRESPONSE, WHYBAD, DATE, PAYMENTMETHODS)>
  <!ELEMENT ACCOUNT (#PCDATA)>
  <!ELEMENT DATE (#PCDATA)>
  <!ELEMENT GOODRESPONSE (#PCDATA)>
  <!ELEMENT WHYBAD (#PCDATA)>
  <!ELEMENT PAYMENTMETHODS (CREDITCARD?,CHECK?,WEB900?)>
  <!ELEMENT CREDITCARD (CREDITCARDATTEMPT*)>
  <!ELEMENT CHECK (CHECKATTEMPT*)>
  <!ELEMENT WEB900 (WEB900ATTEMPT*)>
  <!ELEMENT CREDITCARDATTEMPT (TRANS, AMOUNT, FIRSTNAME, LASTNAME, CITY, STATE, ZIPCODE, COUNTRY, EMAILADDRESS, 
    IPADDRESS, PHONENUMBER, APPROVED, PINCODE, USERNAME, PASSWORD, WHYDECLINED, REFUNDED, CHARGEDBACK, TRANSACTIONTIME, 
EVENTTYPE, REVSHARERID, SUBSCRIPTIONID)>
  <!ELEMENT CHECKATTEMPT (TRANS, AMOUNT, FIRSTNAME, LASTNAME, CITY, STATE, ZIPCODE, EMAILADDRESS, IPADDRESS, PHONENUMBER, 
    APPROVED, PINCODE, USERNAME, PASSWORD, WHYDECLINED, REFUNDED, CHARGEDBACK, REVOKED, TRANSACTIONTIME, EVENTTYPE, REVSHARERID,
 SUBSCRIPTIONID)> 
  <!ELEMENT WEB900ATTEMPT (TRANS, AMOUNT, CODE1, CODE2, REFUNDED, TRANSACTIONTIME)>
  <!ELEMENT TRANS (#PCDATA)>
  <!ELEMENT PINCODE (#PCDATA)>
  <!ELEMENT USERNAME (#PCDATA)>
  <!ELEMENT PASSWORD (#PCDATA)>
  <!ELEMENT AMOUNT (#PCDATA)>
  <!ELEMENT FIRSTNAME (#PCDATA)>
  <!ELEMENT LASTNAME (#PCDATA)>
  <!ELEMENT CITY (#PCDATA)>
  <!ELEMENT STATE (#PCDATA)>
  <!ELEMENT ZIPCODE (#PCDATA)>
  <!ELEMENT COUNTRY (#PCDATA)>
  <!ELEMENT EMAILADDRESS (#PCDATA)>
  <!ELEMENT IPADDRESS (#PCDATA)>
  <!ELEMENT PHONENUMBER (#PCDATA)>
  <!ELEMENT APPROVED (#PCDATA)>
  <!ELEMENT WHYDECLINED (#PCDATA)>
  <!ELEMENT REFUNDED (#PCDATA)>
  <!ELEMENT CHARGEDBACK (#PCDATA)>
  <!ELEMENT REVOKED (#PCDATA)>
  <!ELEMENT TRANSACTIONTIME (#PCDATA)>
  <!ELEMENT EVENTTYPE (#PCDATA)>
  <!ELEMENT REVSHARERID (#PCDATA)>
  <!ELEMENT SUBSCRIPTIONID (#PCDATA)>
  <!ELEMENT CODE1 (#PCDATA)>
  <!ELEMENT CODE2 (#PCDATA)>
]>


<TRANSDETAIL>
    <RESPONSE>
      <ACCOUNT>99999100</ACCOUNT>
      <GOODRESPONSE>YES</GOODRESPONSE>
      <WHYBAD>NO ERROR</WHYBAD>
      <DATE>01/01/1999</DATE>
      <PAYMENTMETHODS>


         </PAYMENTMETHODS>
     </RESPONSE>
</TRANSDETAIL>
<?END TRANSDETAIL?>