PHP5 class to get Alexa traffic rank

[123finder.com]

This PHP5 class utilizes the web service provided by Alexa/Amazon to get the traffic information about the site. You'll need to sign up for an account at Alexa to get the pair (access key and secret key). The first 10,000 queries per month are free.

<?php
/** 
* @author Son Nguyen
* @since 3/31/2006
* @package Framework
* @subpackage WebServices
*/
class CAlexaAPI {
  private $mParams;
  private $mSecretKey = 'YOUR SECRET KEY'; 
  /** constructor */
  function __construct() {
    $this->mParams = array(
      'Service'=>'AlexaWebInfoService',
      'AWSAccessKeyId'=>'YOUR ACCESS KEY', // access key id
      'Operation'=>'UrlInfo',
      'ResponseGroup'=>'Rank',
      'Url'=>NULL,
      'Timestamp'=>gmdate('Y-m-d\TH:i:s.000\Z'),
      'Signature'=>NULL,
    );
    $this->prepareSignature();
  }

  /** ref: http://developer.amazonwebservices.com/connect/thread.jspa?threadID=9675 */
  private function calculate_RFC2104HMAC ($data, $key) {
    return base64_encode(
      pack("H*", sha1((str_pad($key, 64, chr(0x00))
      ^(str_repeat(chr(0x5c), 64))) .
      pack("H*", sha1((str_pad($key, 64, chr(0x00))
      ^(str_repeat(chr(0x36), 64))) . $data))))
    );
  }


  /** have the signature ready */
  private function prepareSignature() {
    $vData = $this->mParams['Service'].$this->mParams['Operation'].$this->mParams['Timestamp'];
    $this->mParams['Signature'] = $this->calculate_RFC2104HMAC($vData,$this->mSecretKey);
  }
  

  /** make the rest call and return result as XML object */
  function call() {
    $vURL = 'http://awis.amazonaws.com/onca/xml?';
    $vTmp = array();
    foreach ($this->mParams AS $vKey=>$vValue) {
      $vTmp[] = $vKey.'='.$vValue;
    } // rof
    $vURL .= implode('&',$vTmp);
    $vFile = file_get_contents($vURL);
    $vXML = simplexml_load_string($vFile);
    return $vXML;
  }

  /** get the rank for a domain */
  function getRank($pDomain) {
    $this->mParams['Url'] = $pDomain;
    $vResult = $this->call();
    $vResult = $vResult->UrlInfoResult->Alexa->TrafficData->Rank+0;
    return $vResult;
  }
}
?>