https://github.com/AcademicTorrents/torrentify

_packages/web-seeds/create.php

+<?php
+
+function safe_b64encode($string) {
+  $data = base64_encode($string);
+  $data = str_replace(array('+','/','='),array('-','_',''),$data);
+  return $data;
+}
+
+class Torrent {
+  public $metadata;
+  public $name;
+  public $id;
+  
+  function __construct ($url_or_file) {
+    $this->name = urldecode(end(explode('/', $url_or_file)));
+    $this->id = safe_b64encode($url_or_file);
+
+    $filesize = (int) array_change_key_case(
+      get_headers($url_or_file, TRUE))['content-length'];
+    $piece_size = $this->get_piece_size($filesize);
+    $log = getcwd() . "/log/" . $this->id;
+
+    # now create the actual torrent
+    $this->metadata = array(
+        'announce' => 'http://academictorrents.com/announce.php',
+        'encoding' => 'UTF-8',
+        'info' => array(
+            'length'       => $filesize,
+            'name'         => $this->name,
+            'pieces'       => $this->make_pieces($url_or_file, $piece_size,
+                                                 $filesize, $log),
+            'piece length' => $piece_size,
+        ),
+        'url-list' => array($url_or_file),
+    );
+    $this->save();
+  }
+
+  static function bencode($var) {
+    if (is_int($var)) {
+      return 'i' . $var . 'e';
+    } else if (is_string($var)) {
+      return strlen($var) . ':' . $var;
+    } else if (is_array($var)) {
+      # must distinguish between dict and list
+      for ($i = 0; $i < count($var); $i++) {
+        # if dict, cannot index using ints?
+        if (!isset($var[$i])) {
+          $dictionary = $var;
+          ksort($dictionary);
+          $ret = 'd';
+          foreach ($dictionary as $key => $value) {
+            $ret .= Torrent::bencode($key) . Torrent::bencode($value);
+          }
+          return $ret . 'e';
+        }
+      }
+      $ret = 'l';
+      foreach ($var as $value) {
+        $ret .= Torrent::bencode($value);
+      }
+      return $ret . 'e';
+    }
+  }
+
+  private function get_piece_size($filesize) {
+    $piece_length = 524288;
+    while (ceil($filesize / $piece_length) == 1) {
+        $piece_length /= 2;
+    }
+    while (ceil($filesize / $piece_length) > 1500) {
+        $piece_length *= 2;
+    }
+    return $piece_length;
+  }
+
+  private function make_pieces($url, $piece_length, $filesize, $logfile) {
+    if (($fp = fopen($url, 'r')) == FALSE) {
+        return FALSE;
+    }
+    $pieces = '';
+    $part = '';
+
+    $position = 0;
+    $i = 0;
+    while ($position < $filesize) {
+      $bytes_read = 0;
+      # fread doesn't actually read in the correct number of bytes
+      # piece together multiple freads
+      while ($bytes_read < $piece_length && $position < $filesize) {
+        $this_part = fread($fp, min($piece_length, $filesize - $position));
+        $bytes_read += strlen($this_part);
+        $position += strlen($this_part);
+        $part .= $this_part;
+      }
+      $next_part = substr($part, $piece_length);
+      $part = substr($part, 0, $piece_length);
+      $piece = sha1($part, $raw_output=TRUE);
+      $pieces .= $piece;
+
+      $part = $next_part;
+
+      if ($position > $filesize) {
+        $position = $filesize;
+      }
+      # log progress every 5 pieces
+      if ($i++ % 5 == 0 || $position == $filesize) {
+        $log = fopen($logfile, "w");
+        fwrite($log, $position . '/' . $filesize);
+        fflush($f);
+        fclose($log);
+      }
+    }
+    fflush($f);
+    fclose($fp);
+    return $pieces;
+  }
+
+  private function save() {
+    $dir = getcwd() . "/torrents/" . $this->id; 
+    mkdir($dir);
+    $f = fopen($dir . "/" . $this->name . ".torrent", "w");
+    fwrite($f, Torrent::bencode($this->metadata));
+    fflush($f);
+    fclose($f);
+  }
+}
+
+/*
+ create:
+ 1. Input: GET variables url-encoded string "url".
+ 2. Creates log for "id" in ./log/ for the download.
+ 3. Streamingly creates torrent, updating log.
+ 4. Dumps finished torrent file in ./torrents/
+*/
+
+# Main
+if (isset($_GET["url"]) && filter_var($_GET["url"], FILTER_VALIDATE_URL)) {
+  $logname = getcwd() . "/log/" . safe_b64encode($_GET["url"]);
+
+  # if log exists, don't start new torrent
+  if (file_exists($logname)) {
+    # check status; return "done", or "processing"
+    $contents = explode("/", stream_get_contents(fopen($logname, "r")));
+    $progress = intval($contents[0]);
+    $total = intval($contents[1]);
+    if ($progress==$total) {
+      echo(json_encode(array(
+        'status' => 'OK',
+        'msg' => "Torrent complete!")));
+    } else {
+      echo(json_encode(array(
+        'status' => 'OK',
+        'msg' => "Torrent already processing!")));
+    }    
+  } else {
+    $torrent = new Torrent($_GET["url"]);
+  }
+} else {
+  echo(json_encode(array(
+    'status' => 'ERROR',
+    'msg' => "Requires GET variable 'url'")));
+};
+?>

design/publicheader.php

 <?php if (OPEN_REGISTRATION) { ?>
  | <a href="register.php">Register</a>
 <?php } ?>
+| <a href="mailto:help@biotorrents.de?subject=[TxID <?= strtoupper(bin2hex(random_bytes(2))) ?>] Vague subject lines ignored">Support</a>
 </span></div>
 <div id="content">
 
     <!-- todo: Put index page stats here -->
-    <?php #include('/sections/login/stats.php'); ?>
+    <?php #include('/sections/login/stats.php');?>
 
   <table class="layout" id="maincontent">
     <tr>