Download google-pagerank.zip - 515.4 KB
Google�s PageRank (PR) is a "link analysis algorithm measuring the relative importance" (PR @wikipedia). The importance of PR nowadays is a lot lower, than one or two years ago. Never the less, PR is the only Ranking value, that is public to all audience, which means it�s the only factor with some transparency. For those, who don�t know: a PR of 10 is the highest around (like apple.com) and 0 the lowest - those sites, who don�t even have a PR of 0 are in a kind of sandbox (a special filter to punish the site) or not indexed by google.
Please forgive me for beeing lazy in the english lessons @ school as I�m trying my best :)
Google tries to measure the relevance of a domain/site by counting the links pointing to the site/domain. This is influenced by the number of links, that link to the linking site - in fact this kind of procedure is an iterative process, which needs a lot computing power.
Many webmasters believe, their ranking depends on the PR of their site - this, today, is not true. PR never was the only factor for google�s ranking, but it was the most important factor. Right now, it�s not. And many people believe, that google tries to get rid of the RageRank, because link traders are measuring the value (in $) of a link by PR - which is just stupid.
If you�re interested in buying links, go with following factors:
Well, the easy part it, how the PR get�s requestet: it�s just a simpel HTTP-Request, with a little problem in it: here�s the request for www.codeproject.com
// http://toolbarqueries.google.com/search?client=navclient-auto&hl=en&ch=6771535612&ie=UTF-8 &oe=UTF-8&features=Rank&q=info:http%3A%2F%2Fwww.codeproject.com%2F //
Well, this seems to be easy, but there�s this little
ch=6771535612
which is a hash value, referencing the domain we want to get the PR for. This hashing algorithm was NOT developed by google, it�s the perfect hashing algorithm by Bob Jenkins
After some folks ported the code to php, I tried to do a port to C# - and here we go.
At first I need to mention, that (after I finished my coding) I found another port my Miroslav Stompar, which you can find here
To be honest, his port was better, so I modified my version and here comes the solution, that�s my favorite:
"Google_Pagerank/google-pagerank.zip">Download google-pagerank.zip - 515.4 KBusing System; using System.Collections.Generic; using System.Text; using System.Text.RegularExpressions; using System.Net; using System.IO; namespace GooglePR { class GetPR { private const UInt32 myConst = 0xE6359A60; private static void _Hashing(ref UInt32 a, ref UInt32 b, ref UInt32 c) { a -= b; a -= c; a ^= c >> 13; b -= c; b -= a; b ^= a << 8; c -= a; c -= b; c ^= b >> 13; a -= b; a -= c; a ^= c >> 12; b -= c; b -= a; b ^= a << 16; c -= a; c -= b; c ^= b >> 5; a -= b; a -= c; a ^= c >> 3; b -= c; b -= a; b ^= a << 10; c -= a; c -= b; c ^= b >> 15; } public static string PerfectHash(string theURL) { url = string.Format("info:{0}", theURL); int length = url.Length; UInt32 a, b; UInt32 c = myConst; int k = 0; int len = length; a = b = 0x9E3779B9; while (len >= 12) { a += (UInt32)(url[k + 0] + (url[k + 1] << 8) + (url[k + 2] << 16) + (url[k + 3] << 24)); b += (UInt32)(url[k + 4] + (url[k + 5] << 8) + (url[k + 6] << 16) + (url[k + 7] << 24)); c += (UInt32)(url[k + 8] + (url[k + 9] << 8) + (url[k + 10] << 16) + (url[k + 11] << 24)); _Hashing(ref a, ref b, ref c); k += 12; len -= 12; } c += (UInt32)length; switch (len) { case 11: c += (UInt32)(url[k + 10] << 24); goto case 10; case 10: c += (UInt32)(url[k + 9] << 16); goto case 9; case 9: c += (UInt32)(url[k + 8] << 8); goto case 8; case 8: b += (UInt32)(url[k + 7] << 24); goto case 7; case 7: b += (UInt32)(url[k + 6] << 16); goto case 6; case 6: b += (UInt32)(url[k + 5] << 8); goto case 5; case 5: b += (UInt32)(url[k + 4]); goto case 4; case 4: a += (UInt32)(url[k + 3] << 24); goto case 3; case 3: a += (UInt32)(url[k + 2] << 16); goto case 2; case 2: a += (UInt32)(url[k + 1] << 8); goto case 1; case 1: a += (UInt32)(url[k + 0]); break; default: break; } _Hashing(ref a, ref b, ref c); return string.Format("6{0}", c); } public static int MyPR(string myURL) { string strDomainHash = PerfectHash(myURL); string myRequestURL = string.Format("http://toolbarqueries.google.com/ search?client=navclient-auto&ch={0}&features=Rank&q=info:{1}", strDomainHash, myURL); try { HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(myRequestURL); string myResponse = new StreamReader(myRequest.GetResponse().GetResponseStream()).ReadToEnd(); if (myResponse.Length == 0) return 0; else return int.Parse(Regex.Match(myResponse, "Rank_1:[0-9]:([0-9]+)").Groups[1].Value); } catch (Exception) { return -1; } } } }So many thx to Miroslav, who did the better job :)
Here you can find the ASP.NET-Version of a PR-Checker - this one checks the PR of the given Domain/Site of different IPs, which means different google Datacenters. Because google only updates the shown PR (Toolbar PR) about every 3 months, this tool is nice to check, if there�s an update running - while the update runs, you�ll get different PRs for the same page (in case, that the PR raises or falls) - interesting, isn�t it?
To check more than one Datacenter, I just created a loop and dynamically replace the
toolbarqueries.google.com
part of the request with a google IP - a list of IPs can be found via google :)
If the tool shows "-1" the PR couldn�t be retrieved, due to any reason
0.2 Uploaded Source-Code
I got to mention something first: if you�re using the uploaded example, then u�re
using the code by miro stampar - for some reasons my Code is blown up with other
things, I�m still working on. So don�t worry, why the code differs from the code in this article
0.1 correction of a variable name (myURL to url) - thx to CP-user ploufs :)
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