Google PR. How is it calculated?

[smlbsns]

I wonder what formula is used by Google to calculate a page rank for some particular page. Any ideas?

[sowar]

The Google PR formula is not a secret. See:

PR(A) = (1-d) + d(PR(t1)/C(t1) + ... + PR(tn)/C(tn))

Here PR(A) is the page rank boost your page A will get after being linked from someone else's site (t1). PR(t1) is the page rank of the page which links to you and C(t1) is the amount of total links that (t1) has.

Imagine your site was linked by someone's link page which had a PR of 4 and 9 other links, here's how the formula should look like:

PR(AKA) = (1-0.85) + 0.85*(4/10)
PR(AKA) = 0.15 + 0.85*(0.4)
PR(AKA) = 0.15 + 0.34
PR(AKA) = 0.49

0.85 above is damping factor - the amount of your PR which you can actually pass on when you link to another site.

To sum up my site would get an injection of 0.49 PR after being linked from a page with a PR of four and 9 other links.

Let's say you were linked from a site with a PR of 8, double the previous example's amount, which had 15 other links, a total of 16 outbound links, your boost would be:

PR(AKA) = (1-0.85) +0.85*(8/16)
PR(AKA) = 0.15 + 0.85(0.5)
PR(AKA) = 0.15 + 0.425
PR(AKA) = 0.575

[omni56]

Here a good article about PR calculation: http://www.webworkshop.net/pagerank.html

[smlbsns]

Thank you guys especially for the article at webworkshop.net, but is there any script what allows one to calculate/retrieve the page rank for a given url? I was searching for it but haven't found anything

[sowar]

As far as I know there is no "legal" way to get pagerank for a list of sites/pages that do not violate the Google's rules. All the 3rd party scripts doing this are NOT obeying Google's ToS.

[smutboy]

You should always check hotscripts.com before to ask about any script on boards, because hotscripts.com has almost everything! So this is a link to php script which calculates google pr: http://hotscripts.com/Detailed/37856.html

[smlbsns]

Thanks for the url, but the script there is CRYPTED so I just can't see the source

[smutboy]

Replace eval by echo and run the script. Now look at the HTML source - encrypted junk turns into normal readable PHP code!

P.S. I could post Google pr calculator code right here.

[smlbsns]

Still can't see a shit. The code is crypted! smutboy, send the encrypted code to my PM please.

[smutboy]

Ok, here we go:

Code: Select all

<?php
define('GOOGLE_MAGIC', 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 GoogleCH($url, $length=null, $init=GOOGLE_MAGIC) {
    if(is_null($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;
}


// converts an array of 32 bit integers into an array with 8 bit values. Equivalent to (BYTE *)arr32

function c32to8bit($arr32) {
    for($i=0;$i<count($arr32);$i++) {
        for ($bitOrder=$i*4;$bitOrder<=$i*4+3;$bitOrder++) {
            $arr8[$bitOrder]=$arr32[$i]&255;
            $arr32[$i]=zeroFill($arr32[$i], 8);
        }     
    }
    return $arr8;
}


function GetGooglePR($url)
    {
    $url = 'info:'.$url;
    $ch = GoogleCH(strord($url));
    $ch = ((($ch/7) << 2) | (((int)fmod($ch,13))&7));
    $prbuf = array();
    $prbuf[0] = $ch;
    for($i = 1; $i < 20; $i++)
        {
        $prbuf[$i] = $prbuf[$i-1]-9;
        }
    $ch = GoogleCH(c32to8bit($prbuf), 80);
   
//    $ch=sprintf("%u", $ch);
    $HEAD = "GET /search?sourceid=navclient-ff&features=Rank&client=navclient-auto-ff&ch=".sprintf("6%u",$ch)."&q=".urlencode($url)." HTTP/1.1\r\n";
    $HEAD.= "Host: toolbarqueries.google.com\r\n";
    $HEAD.= "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.8) Gecko/20051111 Firefox/1.5\r\n";
    $HEAD.= "Accept: text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/"."*;q=0.5\r\n";
    $HEAD.= "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7\r\n";
    $HEAD.= "Connection: Close\r\n";
    $HEAD.= "Cache-Control: max-age=0\r\n";
    $HEAD.= "Pragma: no-cache\r\n";
    $HEAD.= "Content-type: text/xml\r\n";
    $HEAD.= "\r\n";

$fp = fsockopen("toolbarqueries.google.com", "80", $errno, $errstr, 10);
    if (!$fp)
        {
        echo "$errstr ($errno)<br />\n";
        return "";
        }
    else
        {
        fputs($fp, $HEAD);
        $Result="";
        while (!feof($fp))
            {
            $Result.=fgets($fp, 4096);
            }
        fclose($fp);
        }
       
    if(strpos($Result,"Rank_"))
        {
        $Result=substr($Result,strpos($Result,"Rank_")+5);
        $Result=trim(substr($Result,strpos($Result,":")+1));
        $Result=trim(substr($Result,strpos($Result,":")+1));
        $Result=trim(substr($Result,0,strpos($Result,"\n")));
        }
    else
        $Result=-1;
           
    return $Result;
    }
echo GetGooglePR("http://yourdomain.com");
?>


[cyberxxx]

Here is a new working code:

Code: Select all

<?php
class PageRank
{
   /*
    * convert a string to a 32-bit integer
    */
   function ConvertStrToInt($Str, $Check, $Magic)
   {
       $Int32Unit = 4294967296;  // 2^32

       $length = strlen($Str);
       for ($i = 0; $i < $length; $i++) {
           $Check *= $Magic;
           //If the float is beyond the boundaries of integer (usually +/- 2.15e+9 = 2^31),
           //  the result of converting to integer is undefined
           //  refer to http://www.php.net/manual/en/language.types.integer.php
           if ($Check >= $Int32Unit) {
               $Check = ($Check - $Int32Unit * (int) ($Check / $Int32Unit));
           }
           $Check += ord($Str{$i});
       }
       return $Check;
   }

   /*
    * Genearate a hash for a url
    */
   function HashURL($String)
   {
       $Check1 = $this->ConvertStrToInt($String, 0x1505, 0x21);
       $Check2 = $this->ConvertStrToInt($String, 0, 0x1003F);

       $Check1 >>= 2;
       $Check1 = (($Check1 >> 4) & 0x3FFFFC0 ) | ($Check1 & 0x3F);
       $Check1 = (($Check1 >> 4) & 0x3FFC00 ) | ($Check1 & 0x3FF);
       $Check1 = (($Check1 >> 4) & 0x3C000 ) | ($Check1 & 0x3FFF);

       $T1 = (((($Check1 & 0x3C0) << 4) | ($Check1 & 0x3C)) <<2 ) | ($Check2 & 0xF0F );
       $T2 = (((($Check1 & 0xFFFFC000) << 4) | ($Check1 & 0x3C00)) << 0xA) | ($Check2 & 0xF0F0000 );

       return ($T1 | $T2);
   }

   /*
    * genearate a checksum for the hash string
    */
   function CheckHash($Hashnum)
   {
       $CheckByte = 0;
       $Flag = false;

       $HashStr = sprintf('%u', $Hashnum) ;
       $length = strlen($HashStr);

       for ($i = $length - 1;  $i >= 0;  $i --) {
           $Re = $HashStr{$i};
           if ($Flag) {
               $Re += $Re;
               $Re = (int)($Re / 10) + ($Re % 10);
           }
           $CheckByte += $Re;
           $Flag = !$Flag;
       }

       $CheckByte %= 10;
       if (0 !== $CheckByte) {
           $CheckByte = 10 - $CheckByte;
           if ($Flag) {
               if (1 === ($CheckByte % 2)) {
                   $CheckByte += 9;
               }
               $CheckByte >>= 1;
           }
       }

       return '7'.$CheckByte.$HashStr;
   }

   function getRank($url)
   {
      //$ch = "6" . $this->GoogleCH($this->strord("info:" . $url));
      $ch = $this->CheckHash($this->HashURL($url));
      $pagerank = -1;
      $fp = fsockopen("www.google.com", 80, $errno, $errstr, 10);
      if (!$fp)
      {
         echo "$errstr ($errno)<br />\n";
      }
      else
      {
         $out = "GET /search?client=navclient-auto&ch=" . $ch . "&features=Rank&q=info:" . $url . " HTTP/1.1\r\n";
         $out .= "Host: google.com\r\n";
         $out .= "Connection: Close\r\n\r\n";
         fwrite($fp, $out);
         while (!feof($fp))
         {
            //stream_set_timeout($fp, 10);
            $data = fgets($fp, 128);
            $pos = strpos($data, "Rank_");
            if ($pos === false)
            {
            }
            else
            {
               $pagerank = trim(substr($data, $pos +9));
            }
         }
         fclose($fp);
      }
      return $pagerank;
   }
}

$url = 'http://google.com/';

$pr = new PageRank();
$result = $pr->getRank($url);

?>