From e762c01b34ade503c5fa74cc2cd506bb4bb67a42 Mon Sep 17 00:00:00 2001
From: "Janus B. Kristensen" <jbk@visualgroup.dk>
Date: Sun, 17 Jun 2007 13:43:18 +0000
Subject: [PATCH] The .torrent-generator allowing projects to dynamically
 generator .torrent-data for their files.

svn path=/trunk/boinc/; revision=12950
---
 html/bt/torrent_cache.php | 57 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100755 html/bt/torrent_cache.php

diff --git a/html/bt/torrent_cache.php b/html/bt/torrent_cache.php
new file mode 100755
index 0000000000..7201d90171
--- /dev/null
+++ b/html/bt/torrent_cache.php
@@ -0,0 +1,57 @@
+<?php
+/**
+ * The torrent cache and generator script takes care of dynamically generating .torrents
+ * when they are requested by clients.
+ * To optimize performance .torrent-objects are cached in the cache directory so that
+ * on any second request they can be directly sent without re-calculating the SHA1 strings.
+ *
+ * A file is requested by torrent_cache.php?file=/some_file.filetype
+ *
+ * Symlinks outside the $fileDirectory are not allowed. Either do hardlinking or make the
+ * entire $fileDirectory a symlink somewhere.
+ * 
+ * The optional webseeds must be HTTP servers with a similar structure to $fileDirectory
+ * For instance if you have a webseed called "http://burp.boinc.dk/download/" and a file
+ * $fileDirectory/dir/file
+ * then the webseed musst respond to queries on http://burp.boinc.dk/download/dir/file.
+ *
+ * Please see config.php for the setting of these variables.
+ */
+require_once("config.php");
+
+function isSubDir($possibleSubDir, $parent){
+    $realPossible = realpath($possibleSubDir);
+    $realParent = realpath($parent);
+    return (substr($realPossible, 0, strlen($realParent)) == $realParent);
+}
+
+// Get the file request and do some checkups
+$file = $_GET["file"];
+if (!$file) throw new IllegalArgumentException("No file specified");
+if (strpos(urldecode($file), "..")!==false) throw new IllegalArgumentException("Cannot use '..' in path");
+$file = $fileDirectory.$file;
+if (($fileModTime = filemtime($file)) === false) throw new IllegalArgumentException("File does not exist");
+if (!$fileFilter->isValid($file)) throw new IllegalArgumentException("File was not accepted by the server for tracking.");
+
+// Everything's fine let's lookup the .torrent in the cache if needed:
+$cache_args = "file=".$file."&modtime=".$fileModTime;
+$cacheddata=get_cached_data(TORRENT_CACHE_TTL,$cache_args);
+if ($cacheddata){ //If we have got the data in cache
+    $torrent = unserialize($cacheddata); // use the cached data
+} else { //if not do queries etc to generate new data
+   for ($i=0; $i<sizeof($webseeds);$i++){
+       $realWebseeds[] = $webseeds[$i].substr($file, strlen($fileDirectory));
+   }
+			   
+    $torrent = new Torrent($file, $trackerURL, $realWebseeds);
+    $torrent->ensureSHA1Loaded();
+    db_init();
+    $torrent->register();
+    set_cache_data(serialize($torrent),$cache_args); //save data in cache
+};
+
+header("Content-type: application/x-bittorrent");
+header("Content-Disposition: attachment; filename=\"".basename($file).".torrent\"");
+
+echo $torrent->toEncoded();
+?>
\ No newline at end of file