#!./php-exec
<?php

require_once("PEAR.php");
require_once("Curl.php");

$UserID = posix_getuid();
$UserInfo = posix_getpwuid($UserID);
$UserName = $UserInfo["name"];
#$RequestedFile = $REDIRECT_QUERY_STRING;
$RequestedFile = $_SERVER["REDIRECT_URL"];
$RequestedHost = $_SERVER["HTTP_HOST"];
$BaseDir = dirname($_SERVER["SCRIPT_FILENAME"]);
$TempDir = "$BaseDir/tmp";
#$DataDir = "$BaseDir/Data";
$DataDir = "$BaseDir/" . GetDataDir($RequestedHost);
$LogFileName = "$BaseDir/Log";
$PID = getmypid();
$RemoteIP = $_SERVER["REMOTE_ADDR"];
$DataRange = $_SERVER["HTTP_RANGE"];

# Check DataRanges (from Accept-Range:)
$DataRangePattern = "/bytes=([0-9]+)-([0-9]+)/";
$Result = preg_match($DataRangePattern, $DataRange, $Matches);
if ($Result)
{
   $DataRangeStart = $Matches[1];
   $DataRangeEnd = $Matches[2];
}
else
{
   $DataRangeStart = 0;
   $DataRangeEnd = 0;
   $DataRangePattern = "/bytes=([0-9]+)-/";
   $Result = preg_match($DataRangePattern, $DataRange, $Matches);
   if ($Result) $DataRangeStart = $Matches[1];
}

function RewriteHost($RequestedHost)
{
   if ($RequestedHost == "tst-carpet.cs.byu.edu") return("red-carpet.ximian.com");
   if ($RequestedHost == "test-carpet.cs.byu.edu") return("red-carpet.ximian.com");
   if ($RequestedHost == "red-carpet.cs.byu.edu") return("red-carpet.ximian.com");
   if ($RequestedHost == "red-carpet.ximian.com") return("red-carpet.ximian.com");
   if ($RequestedHost == "apt.cs.byu.edu") return("ayo.freshrpms.net");
   if ($RequestedHost == "ayo.cs.byu.edu") return("ayo.freshrpms.net");
}

function GetDataDir($RequestedHost)
{
   if ($RequestedHost == "tst-carpet.cs.byu.edu") return("Mirrors/RedCarpet");
   if ($RequestedHost == "test-carpet.cs.byu.edu") return("Mirrors/RedCarpet");
   if ($RequestedHost == "red-carpet.cs.byu.edu") return("Mirrors/RedCarpet");
   if ($RequestedHost == "red-carpet.ximian.com") return("Mirrors/RedCarpet");
   if ($RequestedHost == "apt.cs.byu.edu") return("Mirrors/AptRPM");
   if ($RequestedHost == "ayo.cs.byu.edu") return("Mirrors/AptRPM");
}

function RealPath2($path)
{
  $path      = ereg_replace('/+', '/', $path);
   $patharray = explode('/', $path);
   $path      = '';
   $count     = count($patharray); //We have multiple count($patharray) so a minor bit faster.
   for ($i=0; $i<$count; $i++)
   {
      if ( $patharray[$i] == '.' || $patharray[$i]== '..' || ( (($i+1) < $count) && ($patharray[$i+1]== '..')) )
      {
       //If the current pos is a . ignore, if pos+1 == .. ignore, lastly if current = .. ignore.
      }
      else
      {
         $path .= $patharray[$i].'/';
      }
   }
   //Trim trailing slash
   if (!empty($path)) $path = substr($path, 0, -1);
   return $path;
}

function mkpath($path, $mode = 0700)
{
   $dirs = explode("/", RealPath2($path));
   $path = $dirs[0];
   for ($i = 1 ; $i < count($dirs) ; $i ++)
   {
      $path .= "/".$dirs[$i];
      if (!is_dir($path)) mkdir($path, $mode);
   }
}

function GetFileAge($FileName)
{
   $FileStats = stat($FileName);
   $ModTime = $FileStats["mtime"];
   $CurrentTime = date("U");
   return($CurrentTime - $ModTime);
}

function GetFilemtime($FileName)
{
   clearstatcache();
   $FileStats = stat($FileName);
   $ModTime = $FileStats["mtime"];
   return($ModTime);
}

function GetAllowedAge($FileName)
{
   $FileTypes = array("/.*\.png$/i" => "3 weeks",
      "/.*\.rpm/i" => "3 weeks",
      "/.*\.xml.gz/i" => "12 hours",
      "/.*\.xml/i" => "12 hours",
      "/.*\.rdf/i" => "12 hours");

   reset($FileTypes);
   while (list($Index, $Values) = each($FileTypes))
   {
      $Results = preg_match($Index, $FileName, $Matches);
      if ($Results)
      {
         return($Values);
      }
   }
   return("unknown");
}

function GetMimeType($FileName)
{
   $FileTypes = array("/.*\.png$/i" => "image/png",
      "/.*\.rpm/i" => "application/x-rpm",
      "/.*\.xml.gz/i" => "application/x-gzip",
      "/.*\.xml/i" => "text/xml",
      "/.*\.rdf/i" => "text/plain");
# .rpm should be application/x-rpm, but ximian uses application/x-pn-realaudio-plugin

   reset($FileTypes);
   while (list($Index, $Values) = each($FileTypes))
   {
      $Results = preg_match($Index, $FileName, $Matches);
      if ($Results)
      {
         return($Values);
      }
   }
   return("text/html");
}

function GenerateETag($FileName)
{
#   clearstatcache();
   $FileStat = stat($FileName);

   $ETag = "" . dechex($FileStat["ino"]) . "-" . dechex($FileStat["size"]) . "-" . dechex($FileStat["mtime"]);
   return($ETag);
}

# info from http://www.experts-exchange.com/Web/Web_Languages/PHP/Q_20181691.html
function SendFile($FileName)
{
   global $DataRangeStart, $DataRangeEnd, $ActualDataRangeEnd;

   $BlockSize = 4096;
   $ShortName = basename($FileName);
   $Length = filesize($FileName);
   $FileStat = stat($FileName);

# ETag: "??????-FSize_hex-????????
   header("ETag: " . GenerateETag($FileName));
   header("Accept-Ranges: bytes");
   header("Content-Length: $Length");
   header("Connection: close");
   header("Content-Type: " . GetMimeType($FileName));
#header("content-disposition: attachment; filename=$filename");
   $FilePointer = fopen($FileName, "rb");
   if ($DataRangeEnd == 0) $ActualDataRangeEnd = $Length;
   else $ActualDataRangeEnd = $DataRangeEnd;
   if ($DataRangeStart != 0) fseek($FilePointer, $DataRangeStart);

   $CurrentLocation = ftell($FilePointer);
   if ($CurrentLocation + $BlockSize > $ActualDataRangeEnd)
      $BlockSize = $ActualDataRangeEnd - $CurrentLocation;

   while ($Buffer = fread($FilePointer, $BlockSize))
   {
      echo $Buffer;
      flush();
      $CurrentLocation = ftell($FilePointer);
      if ($CurrentLocation + $BlockSize > $ActualDataRangeEnd)
      {
         $BlockSize = $ActualDataRangeEnd - $CurrentLocation;
      }
   }
# looks like speed can be limited somewhat by freading and sleeping:
# http://www.php.net/manual/en/function.fread.php
}

function LogData($Data)
{
   global $LogFile, $PID, $RemoteIP;

   $Date = date("Y-m-d-H:i:s");
   $AppendString = "$Date - pid:$PID - $RemoteIP - ";

   fputs($LogFile, $AppendString . $Data . "\n");
   fflush($LogFile);
}

function OldDownloadFile($RemoteFileName, $LocalFileName)
{
   global $BaseDir, $TempDir;

#   $RemoteFile = fopen("http://red-carpet.ximian.com/$RequestedFileName", "rb");
   $RemoteFile = fopen($RemoteFileName, "rb");
   $TempFileName = tempnam($TempDir, "Download-");
   $LocalFile = fopen($TempFileName, "w");
   while (!feof($RemoteFile))
   {
      $Data = fread($RemoteFile, 10240);
      fwrite($LocalFile, $Data);
   }
   fclose($RemoteFile);
   fclose($LocalFile);

   $ToDir = dirname($LocalFileName);
   if (!file_exists($ToDir))
   {
      mkpath($ToDir, 0755);
   }
#   copy($TempFileName, $ToLocation);
   copy($TempFileName, $LocalFileName);

   unlink($TempFileName);
}

function DownloadFile($RemoteFileName, $LocalFileName)
{
   global $BaseDir, $TempDir;

   $TempFileName = tempnam($TempDir, "Download-");
   $LocalFile = fopen($TempFileName, "w");

   # here, we download the file
#   $fp = fopen("$TempFileName", "w");
   $ch = curl_init("$RemoteFileName");
   curl_setopt($ch, CURLOPT_FILE, $LocalFile);
#   curl_setopt($ch, CURLOPT_HEADER, 0);
#   curl_setopt($ch, CURLOPT_NOBODY, 0);
#   curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
   $Result = curl_exec($ch);
   curl_close($ch);

   fclose($LocalFile);
   $ToDir = dirname($LocalFileName);
   if (!file_exists($ToDir)) mkpath($ToDir, 0755);
   copy($TempFileName, $LocalFileName);
   unlink($TempFileName);
}

function DownloadAndSendFile($RemoteFileName, $LocalFileName)
{
   global $BaseDir, $TempDir, $DataRangeStart, $DataRangeEnd;

   $BlockSize = 4096;

   $ETag = DownloadETag($RemoteFileName);
   $Length = hexdec($ETag[size]);

   if ($DataRangeEnd == 0) $ActualDataRangeEnd = $Length;
   else $ActualDataRangeEnd = $DataRangeEnd;

   $LengthSent = $ActualDataRangeEnd - $DataRangeStart;

   header("ETag: " . $ETag);
   header("Accept-Ranges: bytes");
   header("Content-Length: $LengthSent");
   header("Connection: close");
   header("Content-Type: " . GetMimeType($LocalFileName));

   $TempFileName = tempnam($TempDir, "Download-");
   $TempFile = fopen($TempFileName, "w");

   $RemoteFile = fopen($RemoteFileName, "rb");
   if (! $RemoteFile)
   {
#      header("HTTP/1.1 404 Not Found");
   }
#   LogData("File: $LocalFileName, sending $DataRangeStart - $ActualDataRangeEnd ($DataRangeEnd)");
   while ($Buffer = fgets($RemoteFile, $BlockSize))
   {
      $CurrentLocation = ftell($TempFile); # where we started this buffer
      fwrite($TempFile, $Buffer); # Write to the temp file

      $StartOffset = $DataRangeStart - $CurrentLocation;
      $EndOffset = $ActualDataRangeEnd - $CurrentLocation;
      if ($StartOffset < 0) $StartOffset = 0;
      if ($EndOffset > $BlockSize) $EndOffset = $BlockSize;
#LogData("File: $LocalFileName, CurrentLocation: $CurrentLocation, StartOffset: $StartOffset, EndOffset: $EndOffset");
      if ($StartOffset < $BlockSize)
      {
         $Buffer = substr($Buffer, $StartOffset, $EndOffset - $StartOffset);
      }
      echo $Buffer;
      flush();
   }

   fclose($TempFile);
   $ToDir = dirname($LocalFileName);
   if (!file_exists($ToDir)) mkpath($ToDir, 0755);
   copy($TempFileName, $LocalFileName);
   unlink($TempFileName);
}

function SplitETag($String)
{
   $Pattern = "/([0-9a-f]+)-([0-9a-f]+)-([0-9a-f]+)/";
   $Result = preg_match($Pattern, $String, $Matches);
   if ($Result) return(array("ino" => $Matches[1], "size" => $Matches[2], "mtime" => $Matches[3]));
   return(array("ino" => 0, "size" => 0, "mtime" => 0));
}

function DownloadETag($URL)
{
   # here we get the file headers
   $ch = curl_init("$URL");
   curl_setopt($ch, CURLOPT_HEADER, 1);
   curl_setopt($ch, CURLOPT_NOBODY, 1);
   curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
   $Headers = curl_exec($ch);
   curl_close($ch);

   $HeaderArray = explode("\n", $Headers);
   while ($CurrentHeader = each($HeaderArray))
   {
#      $Pattern = "/ETag: \"([0-9a-f]+)-([0-9a-f]+)-([0-9a-f]+)\"/";
      $Pattern = "/ETag: \"([0-9a-f]+-[0-9a-f]+-[0-9a-f]+)\"/";
      $Result = preg_match($Pattern, rtrim($CurrentHeader[value]), $Matches);
      if ($Result)
      {
         return(SplitETag($Matches[1]));
      }
#      if ($Result) return(array("ino" => $Matches[1], "size" => $Matches[2], "mtime" => $Matches[3]);
   }
   return(array("ino" => 0, "size" => 0, "mtime" => 0));
}

# This is a print_r that returns the data
function My_print_r($Data)
{
   ob_start();
   print_r($Data);
   $Results = ob_get_contents();
   ob_end_clean();
   return ($Results);
}

# function to return output of phpinfo
function My_phpinfo()
{
   ob_start();
   phpinfo();
   $Results = ob_get_contents();
   ob_end_clean();
   return($Results);
}

   $LogFile = fopen($LogFileName, "a");
   $LocalFile = "$DataDir" . $RequestedFile;
   $RemoteFile = "http://" . RewriteHost($RequestedHost) . $RequestedFile;
#   LogData("$RequestedHost");
   if ($DataRangeEnd == 0) $DataRangeString = "($DataRangeStart-)";
   else $DataRangeString = "($DataRangeStart-$DataRangeEnd)";
   LogData("http://$RequestedHost/$RequestedFile $DataRangeString -> $RemoteFile");
   $RemoteETag = array("ino" => 0, "size" => 0, "mtime" => 0);

   if (! strncmp($RequestedFile, "/control/", 9))
   {
      header("Content-type: text/html");
      if (! strncmp($RequestedFile, "/control/phpinfo", 16)) phpinfo();
   }
   else
   {

#$TempLog = fopen("ZZZ", "w");
#$PhpData = My_phpinfo();
#fwrite($TempLog, $PhpData);
#fclose($TempLog);

      if (file_exists($LocalFile))
      {
         $LocalETagString = GenerateETag($LocalFile);
         $LocalETag = SplitETag($LocalETagString);

         $CurrentTime = strtotime("now");
         $Filectime = filectime($LocalFile);
         $Filemtime = $LocalETag["mtime"];
         $AllowedAge = GetAllowedAge($LocalFile);
         if ($AllowedAge == "unknown") $AllowedTime = strtotime("-1 day", $CurrentTime);
         else $AllowedTime = strtotime("-$AllowedAge", $CurrentTime);

#         LogData("File $RequestedFile has mtime of " . date("Y-m-d-H:i:s", $Filemtime) . ", ctime of " . date("Y-m-d-H:i:s", $Filectime));
         if ($Filectime < $AllowedTime)
         {
            # File is old enough to check.  Test the ETag
            $RemoteETag = DownloadETag($RemoteFile);
#            LogData("RemoteETag data: " . $RemoteETag["ino"] . "-" . $RemoteETag["size"] . "-" . $RemoteETag["mtime"] . " (" . date("Y-m-d-H:i:s", hexdec($RemoteETag["mtime"])) . ")");

#LogData("LocalETag data: " . $LocalETag["ino"] . "-" . $LocalETag["size"] . "-" . $LocalETag["mtime"]);

            # test the etag, and if it's different, delete the file
            if (($RemoteETag["size"] != $LocalETag["size"]) || ($RemoteETag["mtime"] != $LocalETag["mtime"]))
            {
#               LogData("File $RequestedFile is " . ($CurrentTime - $Filemtime) . " seconds old, and ETag has changed.  Deleting.");
               LogData("File $RequestedFile has new ETag.  Deleting.");
               unlink($LocalFile);
            }
         }
      }
      clearstatcache();
      if (! file_exists($LocalFile))
      {
         LogData("Downloading $RemoteFile");
         DownloadAndSendFile($RemoteFile, $LocalFile);
         touch($LocalFile, hexdec($RemoteETag["mtime"]));
      }
      else SendFile($LocalFile);
   }
   fclose($LogFile);
?>