En este POST veremos como obtener el PageRank de Google.
Según la Wikipedia ...
PageRank es una marca registrada y patentada1 por Google el 9 de enero de 1999 que ampara una familia de algoritmos utilizados para asignar de forma numérica la relevancia de los documentos (o páginas web) indexados por un motor de búsqueda.
Sus propiedades son muy discutidas por los expertos en optimización de
motores de búsqueda. El sistema PageRank era utilizado por el popular
motor de búsqueda Google para ayudarle a determinar la importancia o relevancia de una página. Fue desarrollado por los fundadores de Google, Larry Page y Sergey Brin, en la Universidad de Stanford.
Copia el siguiente código y guárdalo como class.google.pr.php
<?php
/**********************************************************************
GooglePR -- Calculates the Google PageRank of a specified URL
Authors : Emre Odabas (emre [at] golge [dot] net)
Version : 2.0
Description
What is Google PageRank?
PageRank is a family of algorithms for assigning numerical weightings
to hyperlinked documents (or web pages) indexed by a search engine.
Its properties are much discussed by search engine optimization (SEO)
experts. The PageRank system is used by the popular search engine
Google to help determine a page's relevance or importance.
As Google puts it:
> PageRank relies on the uniquely democratic nature of the web by
> using its vast link structure as an indicator of an individual
> page's value. Google interprets a link from page A to page B as
> a vote, by page A, for page B. But Google looks at more than the
> sheer volume of votes, or links a page receives; it also analyzes
> the page that casts the vote. Votes cast by pages that are
> themselves "important" weigh more heavily and help to make other
> pages "important."
For more info:
http://www.google.com/corporate/tech.html
http://en.wikipedia.org/wiki/PageRank
http://www.google.com/webmasters/4.html
This class will calculate and return the Google PageRank of the
specified input URL as integer. Class was build based on Raistlin
Majere's google_pagerank function
Change Log:
2008-01-24 * Hash calculation functions updated because of
miscalculation based on php versions.
(algorithm updated based on a anonymous source
code which supposed to be found at
http://pagerank.gamesaga.net but not exists
any more.)
2005-12-07 * Small bug removed (dies when caching disabled)
2005-11-24 * Added user-agent support
* Class selects random google hostnames in
order to prevent abuse. (You may define extra
google hostnames)
* Class now first tries cURL, fsockopen() and
file_get_contents() to connect google servers.
* Added caching option to class. Results now can be
cached to flat files in order to prevent abuse and
increase performance.
* Cache files are stored in seperate directories for
performance issues.
2005-11-04 * Initial version released
Ex:
$gpr = new GooglePR();
//$gpr->debug=true; //Uncomment this line to debug query process
echo $gpr->GetPR("http://www.progen.com.tr");
//Uncomment following line to view debug results
//echo "<pre>";print_r($gpr->debugResult);echo "</pre>
";
**********************************************************************/
Class GooglePR {
//Public vars
var $googleDomains = Array(
"toolbarqueries.google.com",
"www.google.com",
"toolbarqueries.google.com.tr",
"www.google.com.tr",
"toolbarqueries.google.de",
"www.google.de",
"64.233.187.99",
"72.14.207.99");
var $debugResult = Array();
var $userAgent = "Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20021204";
var $cacheDir = "/tmp";
var $maxCacheAge = 86400; // = 24h (yes, in seconds)
var $useCache = false;
var $debug = false;
//Private vars
var $PageRank = -1;
var $cacheExpired = false;
function GetPR($url,$forceNoCache = false) {
$total_exec_start = $this->microtimeFloat();
$result=array("",-1);
if (($url.""!="")&&($url.""!="http://")) {
$this->debugRes("url", $url);
$this->cacheDir .= (substr($this->cacheDir,-1) != "/")? "/":"";
// check for protocol
$url_ = ((substr(strtolower($url),0,7)!="http://")? "http://".$url:$url);
$host = $this->googleDomains[mt_rand(0,count($this->googleDomains)-1)];
$target = "/search";
$querystring = sprintf("client=navclient-auto&ch=%s&features=Rank&q=%s",
$this->CheckHash($this->HashURL($url_)),urlencode("info:".$url_));
$contents="";
$this->debugRes("host", $host);
$this->debugRes("query_string", $querystring);
$this->debugRes("user_agent", $this->userAgent);
$query_exec_start = $this->microtimeFloat();
if ($forceNoCache == true) {
$this->debugRes("force_no_cache", "true");
} elseif ($contents = $this->readCacheResult($url)) {
$this->debugRes("read_from_cache", "true");
} else {
$this->cacheExpired = true;
}
// let's get ranking
if (strlen(trim($contents)) == 0)
if (@function_exists("curl_init")) {
// allways use curl if available for performance issues
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://".$host.$target."?".$querystring);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($ch, CURLOPT_HTTP_VERSION, CURL_HTTP_VERSION_1_0);
curl_setopt($ch, CURLOPT_USERAGENT, $this->userAgent);
if (!($contents = trim(@curl_exec($ch)))) {
$this->debugRes("error","curl_exec failed");
}
curl_close ($ch);
$this->debugRes("method", "curl");
} else {
$this->debugRes("error","curl not installed, trying to use fsockopen");
// use fsockopen as secondary method, to submit user agent
if ($socket = @fsockopen($host, "80", $errno, $errstr, 30)) {
$request = "GET $target?$querystring HTTP/1.0\r\n";
$request .= "Host: $host\r\n";
$request .= "User-Agent: ".$this->userAgent."\r\n";
$request .= "Accept-Language: en-us, en;q=0.50\r\n";
$request .= "Accept-Charset: ISO-8859-1, utf-8;q=0.66, *;q=0.66\r\n";
$request .= "Accept: text/xml,application/xml,application/xhtml+xml,";
$request .= "text/html;q=0.9,text/plain;q=0.8,video/x-mng,image/png,";
$request .= "image/jpeg,image/gif;q=0.2,text/css,*/*;q=0.1\r\n";
$request .= "Connection: close\r\n";
$request .= "Cache-Control: max-age=0\r\n\r\n";
stream_set_timeout ( $socket,10);
fwrite( $socket, $request );
$ret = '';
while (!feof($socket)) {
$ret .= fread($socket,4096);
}
fclose($socket);
$contents = trim(substr($ret,strpos($ret,"\r\n\r\n") + 4));
$this->debugRes("method", "fsockopen");
} else {
$this->debugRes("error","fsockopen failed, trying file_get_contents");
// this way could cause problems because the Browser Useragent is not set...
if ($contents = trim(@file_get_contents("http://".$host.$target."?".$querystring))) {
$this->debugRes("method", "file_get_contents");
} else {
$this->debugRes("error","file_get_contents failed");
}
}
}
if ($this->cacheExpired == true)
$this->updateCacheResult($url,$contents);
$this->debugRes("query_exec_time",$this->microtimeFloat() - $query_exec_start);
$result[0]=$contents;
// Rank_1:1:0 = 0
// Rank_1:1:5 = 5
// Rank_1:1:9 = 9
// Rank_1:2:10 = 10 etc
$p=explode(":",$contents);
if (isset($p[2])) $result[1]=$p[2];
}
if($result[1] == -1) $result[1] = 0;
$this->PageRank =(int)$result[1];
$this->debugRes("total_exec_time", $this->microtimeFloat() - $total_exec_start);
$this->debugRes("result", $result);
return $this->PageRank;
}
function debugRes($what,$sowhat) {
if($this->debug == true) {
$debugbt = debug_backtrace();
$what = trim($what);
$sowhat = trim($sowhat) . " (Line : ".$debugbt[0]["line"].")";
if ($what == "error") {
$this->debugResult[$what][] = $sowhat;
} else {
$this->debugResult[$what] = $sowhat;
}
}
}
function microtimeFloat() {
list($usec, $sec) = explode(" ", microtime());
return ((float)$usec + (float)$sec);
}
function readCacheResult($url) {
if ($this->useCache != true) {
return false;
}
if (!is_dir($this->cacheDir)) {
$this->debugRes("error","please create {$this->cacheDir}");
return false;
}
$urlp = parse_url($url);
$host_ = explode(".",$urlp["host"]);
$path_ = (strlen($urlp["query"])>0)? urlencode($urlp["path"].$urlp["query"]):"default";
$cache_file = $this->cacheDir;
for ($i = count($host_)-1;$i>=0;$i--) {
$cache_file .= $host_[$i]."/";
}
$cache_file .= $path_;
$this->debugRes("cache_file", $cache_file);
if (file_exists($cache_file)) {
$mtime = filemtime($cache_file);
if (time() - $mtime > $this->maxCacheAge) {
$this->debugRes("cache", "expired");
$this->cacheExpired = true;
return false;
} else {
$this->cacheExpired = false;
$this->debugRes("cache_age", time() - $mtime);
return file_get_contents($cache_file);
}
}
$this->debugRes("error","cache file not exists (reading)");
return false;
}
function updateCacheResult($url,$content) {
if ($this->useCache != true) {
return false;
}
if (!is_dir($this->cacheDir)) {
$this->debugRes("error","please create {$this->cacheDir}");
return false;
}
$urlp = parse_url($url);
$host_ = explode(".",$urlp["host"]);
$path_ = (strlen($urlp["query"])>0)? urlencode($urlp["path"].$urlp["query"]):"default";
$cache_file = $this->cacheDir;
for ($i = count($host_)-1;$i>=0;$i--) {
$cache_file .= $host_[$i]."/";
}
$cache_file .= $path_;
if (!file_exists($cache_file)) {
$this->debugRes("error","cache file not exists (writing)");
$cache_file_tmp = substr($cache_file,strlen($this->cacheDir));
$cache_file_tmp = explode("/",$cache_file_tmp);
$cache_dir_ = $this->cacheDir;
for ($i = 0;$i<count($cache_file_tmp)-1;$i++) {
$cache_dir_ .= $cache_file_tmp[$i]."/";
if (!file_exists($cache_dir_)) {
if (!@mkdir($cache_dir_,0777)) {
$this->debugRes("error","unable to create cache dir: $cache_dir_");
//break;
}
}
}
if (!@touch($cache_file)) $this->debugRes("error","unable to create cache file");
if (!@chmod($cache_file,0777)) $this->debugRes("error","unable to chmod cache file");
}
if (is_writable($cache_file)) {
if (!$handle = fopen($cache_file, 'w')) {
$this->debugRes("error", "unable to open $cache_file");
return false;
}
if (fwrite($handle, $content) === FALSE) {
$this->debugRes("error", "unable to write to $cache_file");
return false;
}
fclose($handle);
$this->debugRes("cached", date("Y-m-d H:i:s"));
return true;
}
$this->debugRes("error", "$cache_file is not writable");
return false;
}
//convert a string to a 32-bit integer
function StrToNum($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));
//if the check less than -2^31
$Check = ($Check < -2147483648) ? ($Check + $Int32Unit) : $Check;
}
$Check += ord($Str{$i});
}
return $Check;
}
//genearate a hash for a url
function HashURL($String) {
$Check1 = $this->StrToNum($String, 0x1505, 0x21);
$Check2 = $this->StrToNum($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 = 0;
$HashStr = sprintf('%u', $Hashnum) ;
$length = strlen($HashStr);
for ($i = $length - 1; $i >= 0; $i --) {
$Re = $HashStr{$i};
if (1 === ($Flag % 2)) {
$Re += $Re;
$Re = (int)($Re / 10) + ($Re % 10);
}
$CheckByte += $Re;
$Flag ++;
}
$CheckByte %= 10;
if (0 !== $CheckByte) {
$CheckByte = 10 - $CheckByte;
if (1 === ($Flag % 2) ) {
if (1 === ($CheckByte % 2)) {
$CheckByte += 9;
}
$CheckByte >>= 1;
}
}
return '7'.$CheckByte.$HashStr;
}
}
?>
Una vez guardado en la carpeta dónde quieres probar la clase, crearemos un archivo llamado index.php y le añadimos el siguiente código ...
<?php
error_reporting("WARNING");
include_once("class.googlepr.php");
$pageRank = new GooglePR();
$pageRank->debug = true;
$url = "http://www.google.com";
$result = $pageRank->GetPR($url);
echo "PageRank de $url : " . $result ."\n";
$resultado = $result."0px";
?>
<div style="width: 100px; height: 10px; border-width: 1px; border-color: grey; border-style: solid;">
<div style="width: <?php echo $resultado; ?>; height: 10px; background-color: darkred;"></div>
</div>
Ejecuta el archivo index.php y te aparecerá el pagerank de la url http://www.google.com, también le he añadido una pequeña gráfica, como podemos ver esta clase devuelve un valor comprendido entre 1 y 10 según el grado de importancia o relevancia que tenga para PageRank.
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