Session Share Across Multiple Domains On Same Server
<p>I heard the best method to share session across multiple domains on same server is to use custom php session handler. (ie, domain name different like abc.com, xyz.com but single application.)</p>

<p>But after i tried it, even custom php session handler that using SAME DATABASE ON 1 SERVER can't share session, when i tried to read cookie value from different domain.</p>

<p>Here's my custom session handler, Please kindly check or fix if something missing here. because i've tried it for a week now. can't get it to work</p>

<p>P.S. To get previous session id, i use link such as: newdomain.com/?ssid=[SESSION_ID]
<br>
<br>
<br>
SESSION_INCLUDE.PHP</p>

<pre><code>&lt;?php 

// config 
$m_host = "localhost"; //MySQL Host 
$m_user = "db_user"; //MySQL User 
$m_pass = "db_pass"; //MySQL Pass 
$m_db   = "db_name"; //MySQL Database
$table  = "sess_data";

$session_expire = 600; // Session expire time, in seconds (minutes * 60 = seconds) 

$gc_probability = 100; // Probability that the garbage collection function will be called. 50% chance by default 

ini_set("session.gc_probability",$gc_probability); 

/* Open function; Opens/starts session 

   Opens a connection to the database and stays open until specifically closed 
   This function is called first and with each page load */ 

function open ($s,$n) // do not modify function parameters 
{ 
  global $session_connection, $m_host, $m_user, $m_pass, $m_db; 
  $session_connection = mysql_pconnect($m_host,$m_user,$m_pass); 
  mysql_select_db($m_db,$session_connection); 
  return true; 
} 

/* Read function; downloads data from repository to current session 

   Queries the mysql database, unencrypts data, and returns it. 
   This function is called after 'open' with each page load. */ 
function read ($id) // do not modify function parameters 
{ 
  global $session_connection,$session_read,$table; 
  $query = "SELECT data FROM `$table` WHERE id=\"{$id}\""; 
  $res = mysql_query($query,$session_connection); 
  if(mysql_num_rows($res) != 1) return ""; // must return string, not 'false' 
  else 
  { 
    $session_read = mysql_fetch_assoc($res); 
    $session_read["data"] = base64_decode($session_read["data"]); 
    return $session_read["data"]; 
  } 
} 
function write ($id,$data) // do not modify function parameters 
{ 
  if(!$data) { return false; } 
  global $session_connection, $session_read, $session_expire, $table; 
  $expire = time() + $session_expire; 
  $data = mysql_real_escape_string(base64_encode($data)); 
  if($session_read) $query = "UPDATE `$table` SET data=\"{$data}\", expire=\"{$expire}\" WHERE id=\"{$id}\""; 
  else $query = "INSERT INTO sess_data SET id=\"{$id}\", data=\"{$data}\", expire=\"{$expire}\""; 
  mysql_query($query,$session_connection); 
  return true; 
} 
function close () 
{ 
  global $session_connection; 
  mysql_close($session_connection); 
  return true; 
} 
function destroy ($id) // do not modify function parameters 
{ 
  global $session_connection,$table; 
  $query = "DELETE FROM `$table` WHERE id=\"{$id}\""; 
  mysql_query($query,$session_connection); 
  return true; 
}
function gc ($expire) 
{ 
  global $session_connection,$table; 
  $query = "DELETE FROM `$table` WHERE expire &lt; ".time(); 
  mysql_query($query,$session_connection); 
}
// Set custom handlers 
session_set_save_handler ("open", "close", "read", "write", "destroy", "gc"); 

// Start session 
session_start(); 
?&gt;
</code></pre>

<p><br>
<br>
<br>
MySQL Database Description</p>

<pre><code>create table sess_data (
id2 int not null auto_increment,
id text not null,
data text,
expire int not null,
primary key(id2)
);
</code></pre>
