P2P:Programming:Trackers:Multiscrape

From Depthstrike

Contents 1 General Information 1.1 Request Construction 1.2 Response Contruction 2 Known Tracker Packages with Multiscrape 3 Paramater Parser

General Information

• Multiscraping is done primarily to reduce the overhead generated by multiple scrape requests that amount to less than the tracker's full torrent scrape.
• Whenever information on more than one torrent is required and the number of torrents which information is required on is less than about 90% of the tracker's total torrent list, multiscraping is preferred.
• Individual trackers may outright deny global scraping for bandwidth concerns.

Request Construction

• The following request will ask the specified tracker about all torrents from first_hash through to nth_hash.
• Any torrents the tracker does not know about will not be included in the response.

http://<tracker-address>:<port>/scrape<.php>?info_hash=<first_hash>&info_hash=<second_hash>......&info_hash=<nth_hash>

Response Contruction

• A scrape response will still be returned in such a way as to comply with the BitTorrent Specification Scrape Convention with the difference that the response will include information for each supplied info_hash that the tracker has information on

files
 <first_hash>
  complete = <number of seeds>
  downloaded = <number of times the file has been completed>
  incomplete = <number of downloaders>
  name = <internal name of the torrent (optional)>
 <second_hash>
  complete = <number of seeds>
  downloaded = <number of times the file has been completed>
  incomplete = <number of downloaders>
  name = <internal name of the torrent (optional)>
.....
 <nth_hash>
  complete = <number of seeds>
  downloaded = <number of times the file has been completed>
  incomplete = <number of downloaders>
  name = <internal name of the torrent (optional)>

Known Tracker Packages with Multiscrape

• BitTorrent Official
• BitTornado
• BNBT and current variants
• Azureus
• Apache mod_bt

Paramater Parser

• This is the code to give PHP tracker developers options for scraping multiple torrents in a single request.
• The following code generates a $queryparams array that gives all the paramaters included in the request, even if multiple paramaters have the same name.

$queryinput = explode('&', $_SERVER['QUERY_STRING']);
$queryparams = array();
$count = count($queryinput);
for($i=0; $i<$count; $i++)
{
   $tempparams = explode('=', $queryinput[$i]);
   $queryparams[$tempparams[0]][] = urldecode($tempparams[1]);
   sort($queryparams[$tempparams[0]]);
}

• Another code option (provided by DeHackEd)

foreach (explode("&", $_SERVER["QUERY_STRING"]) as $item) { if (substr($item, 0, 10) == "info_hash=") { ..... }} //

• Another code option (provided by TheColonel)

$count = preg_match_all("/info_hash=([^&?]*)/", $_SERVER['QUERY_STRING'], $matches);

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