friendica/include/session.php

<?php

// Session management functions. These provide database storage of PHP
// session info.

$session_exists = 0;
$session_expire = 180000;

if(! function_exists('ref_session_open')) { 
function ref_session_open ($s,$n) {
  return true;
}}

if(! function_exists('ref_session_read')) { 
function ref_session_read ($id) {
  global $session_exists;
  if(x($id))
    $r = q("SELECT `data` FROM `session` WHERE `sid`= '%s'", dbesc($id));
  if(count($r)) {
    $session_exists = true;
    return $r[0]['data'];
  }
  return '';
}}

if(! function_exists('ref_session_write')) { 
function ref_session_write ($id,$data) {
  global $session_exists, $session_expire;
  if(! $id || ! $data) { 
    return false; 
  }

  $expire = time() + $session_expire;
  $default_expire = time() + 300;

  if($session_exists)
    $r = q("UPDATE `session` 
            SET `data` = '%s', `expire` = '%s' 
            WHERE `sid` = '%s' LIMIT 1", 
            dbesc($data), dbesc($expire), dbesc($id));
  else
    $r = q("INSERT INTO `session`
            SET `sid` = '%s', `expire` = '%s', `data` = '%s'",
            dbesc($id), dbesc($default_expire), dbesc($data));

  return true;
}}

if(! function_exists('ref_session_close')) { 
function ref_session_close() {
  return true;
}}

if(! function_exists('ref_session_destroy')) { 
function ref_session_destroy ($id) {
  q("DELETE FROM `session` WHERE `sid` = '%s'", dbesc($id));
  return true;
}}

if(! function_exists('ref_session_gc')) { 
function ref_session_gc($expire) {
  q("DELETE FROM `session` WHERE `expire` < %d", dbesc(time()));
  q("OPTIMIZE TABLE `sess_data`");
  return true;
}}

$gc_probability = 50;

ini_set('session.gc_probability', $gc_probability);
ini_set('session.use_only_cookies', 1);
ini_set('session.cookie_httponly', 1);


session_set_save_handler ('ref_session_open', 'ref_session_close',
                            'ref_session_read', 'ref_session_write',
                            'ref_session_destroy', 'ref_session_gc');