PHP Tutorial: Finding Google PageRank of a website using PHP

The following code can be used to find the PageRank of a website using PHP. Just copy & paste the below code in a php file and execute it from your browser.

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
<title>PHP PageRank Checker Script</title>
</head>
<body>
<?php
if(isset($_GET['getpr'])){
$myWebSite = ($_POST['url']);
define('GMAG', 0xE6359A60);
//unsigned shift right
function zeroFill($a, $b)
{
$z = hexdec(80000000);
if ($z & $a)
{
$a = ($a>>1);
$a &= (~$z);
$a |= 0x40000000;
$a = ($a>>($b-1));
}
else
{
$a = ($a>>$b);
}
return $a;
}

function mix($a,$b,$c) {
$a -= $b; $a -= $c; $a ^= (zeroFill($c,13));
$b -= $c; $b -= $a; $b ^= ($a<<8);
$c -= $a; $c -= $b; $c ^= (zeroFill($b,13));
$a -= $b; $a -= $c; $a ^= (zeroFill($c,12));
$b -= $c; $b -= $a; $b ^= ($a<<16);
$c -= $a; $c -= $b; $c ^= (zeroFill($b,5));
$a -= $b; $a -= $c; $a ^= (zeroFill($c,3));
$b -= $c; $b -= $a; $b ^= ($a<<10);
$c -= $a; $c -= $b; $c ^= (zeroFill($b,15));

return array($a,$b,$c);
}

function GCH($url, $length=null, $init=GMAG) {
if(is_null($length)) {
$length = sizeof($url);
}
$a = $b = 0x9E3779B9;
$c = $init;
$k = 0;
$len = $length;
while($len >= 12) {
$a += ($url[$k+0] +($url[$k+1]<<8) +($url[$k+2]<<16) +($url[$k+3]
<<24));
$b += ($url[$k+4] +($url[$k+5]<<8) +($url[$k+6]<<16) +($url[$k+7]
<<24));
$c += ($url[$k+8] +($url[$k+9]<<8) +($url[$k+10]<<16)+($url[$k+11]
<<24));
$mix = mix($a,$b,$c);
$a = $mix[0]; $b = $mix[1]; $c = $mix[2];
$k += 12;
$len -= 12;
}

$c += $length;
switch($len) /* all the case statements fall through */
{
case 11: $c+=($url[$k+10]<<24);
case 10: $c+=($url[$k+9]<<16);
case 9 : $c+=($url[$k+8]<<8);
/* the first byte of c is reserved for the length */
case 8 : $b+=($url[$k+7]<<24);
case 7 : $b+=($url[$k+6]<<16);
case 6 : $b+=($url[$k+5]<<8);
case 5 : $b+=($url[$k+4]);
case 4 : $a+=($url[$k+3]<<24);
case 3 : $a+=($url[$k+2]<<16);
case 2 : $a+=($url[$k+1]<<8);
case 1 : $a+=($url[$k+0]);
/* case 0: nothing left to add */
}
$mix = mix($a,$b,$c);
/*-------------------------------------------- report the result */
return $mix[2];
}

//converts a string into an array of integers containing the numeric value of the char
function strord($string) {
for($i=0;$i<strlen($string);$i++) {
$result[$i] = ord($string{$i});
}
return $result;
}

function getPR($_url) {
$url = 'info:'.$_url;
$ch = GCH(strord($url));
$url='info:'.urlencode($_url);
$pr = file("http://www.google.com/search?client=navclient-auto&ch=6$ch&ie=UTF-8&oe=UTF-8&features=Rank&q=$url");
$pr_str = implode("", $pr);
return substr($pr_str,strrpos($pr_str, ":")+1);
}

echo "<br>The PR of ".$myWebSite." is: ".getPR($myWebSite);
}
?>
<form id="frm_pr" name="frm_pr" method="post" action="pr.php?getpr=1">
<table width="60%" border="0" align="center" cellpadding="5" cellspacing="1">
   <tr>
      <td width="30%">Check PageRank & Alexa Rank </td>
      <td><input name="url" id="url" type="text" value="http://<?=str_replace("http://","",$myWebSite)?>" size="55" /></td>
      <td width="15%" align="center"><a href="javascript: document.frm_pr.submit();">Check</a></td>
   </tr>
</table></form>
</body>
</html>