session_handler.php

<?php

function get_sessionconn()
{
  include (dirname(__FILE__) . "/cfgsession.php");
  $sessionconn = mysqli_connect("$dbhost", "$dbuser", "$dbpass", "$db");
  return $sessionconn;
}

function sopen($s, $n)
{
  if (get_sessionconn())
  {
    return true;
  }
  else
  {
    return false;
  }
}

function sread($id)
{
  $sessionconn = get_sessionconn();

  if (!$sessionconn)
  {
    return false;
  }

  $sql = "SELECT 1,`value` FROM `sessions` WHERE `sessionid` = '$id'";
  $result = $sessionconn->query($sql);

  if (mysqli_error($sessionconn) || !$result || !mysqli_num_rows($result))
  {
    $save_path = ini_get("session.save_path");
    if (file_exists($save_path . "/sess_$id"))
    {

      //check if file should have expired already
      $session_duration = ini_get('session.gc_maxlifetime'); //how long a session is good for, in seconds
      $use_file_for_session = true;
      if (filemtime($save_path . "/sess_$id") < time() - $session_duration)
      {
        $use_file_for_session = false;
      }


      //allow fail-over without logging out
      if (file_exists("/tmp/session_use"))
      {
        $use = file_get_contents("/tmp/session_use");
      }
      else
      {
        $use = "";
      }

      try
      {
        if (mysqli_error($sessionconn))
          $message .= ' error, ';
        if (!$result)
          $message .= ' no result, ';
        if ($result)
          $message .= ' result is set ';
        if (!mysqli_num_rows($result))
          $message .= ' no rows, ';
        $to_write = " unable to fetch result ";
        if ($result)
        {
          $data = $result->fetch_assoc();
          $to_write = "print_r: " . print_r($data, true);
        }
      }
      catch (Exception $e)
      {
        
      }
      $message .= $to_write;

      if ($use_file_for_session)
      {
        file_put_contents("/tmp/session_use", $use . "\n" . time() . " using file for " . $id . " error: '" . mysqli_error($sessionconn) . "' sql: '" . $sql . "' message: " . $message);
      }
      else
      {
        file_put_contents("/tmp/session_use", $use . "\n" . time() . " *NOT* using file for " . $id . " error: '" . mysqli_error($sessionconn) . "' sql: '" . $sql . "' message: " . $message);
      }
      return file_get_contents($save_path . "/sess_$id");
    }
    return false;
  }
  $data = $result->fetch_assoc();
  return stripslashes($data['value']);
}

function swrite($id, $data)
{
  $sessionconn = get_sessionconn();
  if (!$sessionconn)
    return false;
  $sql = "REPLACE INTO `sessions` (`sessionid`,`atime`,`value`) VALUES ('$id',NOW(),'" . addslashes($data) . "')";
  $result = $sessionconn->query($sql);
  $save_path = ini_get("session.save_path");
  file_put_contents($save_path . "/sess_$id", $data);
  return true;
}

function sclose()
{
  return true;
}

function sdestroy($id)
{ // do not modify function parameters
  $sessionconn = get_sessionconn();

  if (!$sessionconn)
  {
    return false;
  }

  $sql = "DELETE FROM `sessions` WHERE `sessionid` = '$id' LIMIT 1";
  $result = $sessionconn->query($sql);
  $save_path = ini_get("session.save_path");
  $filename = "$save_path/sess_" . $id;
  @unlink($filename);
  file_put_contents("/tmp/session_destroy", $use . "\n" . time() . " destroying session " . $id);

  if (mysqli_error($sessionconn) || !$result)
  {
    return false;
  }

  return true;
}

function sgc($expire)
{
  $sessionconn = get_sessionconn();
  if (!$sessionconn)
    return false;
  $session_duration = ini_get('session.gc_maxlifetime'); //how long a session is good for, in seconds
  $sql = "DELETE FROM `sessions` WHERE `atime` < DATE_ADD(NOW(), INTERVAL -$session_duration SECOND)"; //delete from the table where the access time is less than (NOW() minus session_duration seconds)
  file_put_contents("/tmp/sql", $sql);
  $result = $sessionconn->query($sql);
  //if (mysqli_error($sessionconn) || !$result) return false;
  $save_path = ini_get("session.save_path");
  $output = time() . " \n";

  foreach (glob("$save_path/sess_*") as $filename)
  {
    //$output .= $filename.":  ".filemtime($filename)." + $session_duration < ".time();
    if (@filemtime($filename) < time() - $session_duration)
    {
      @unlink($filename);
      //$output .= " DELETE \n";
    }
    else
    {
      //$output .= " keep \n";
    }
  }

  file_put_contents("/tmp/session_gc", $output);

  return $result;
}

//session_set_save_handler ("open", "close", "read", "write", "destroy", "gc");
include_once('/var/www/script-repository/session_handler_include.php');
?>