- Improve performance by avoiding unnecessary updates to the session table (#1486325)

1 files changed, 330 insertions, 0 deletions

diff --git a/program/include/rcube_session.php b/program/include/rcube_session.php
new file mode 100644
index 000000000..da799be19
--- /dev/null
+++ b/program/include/rcube_session.php
@@ -0,0 +1,330 @@
+<?php
+
+/*
+ +-----------------------------------------------------------------------+
+ | program/include/rcube_session.php                                     |
+ |                                                                       |
+ | This file is part of the RoundCube Webmail client                     |
+ | Copyright (C) 2005-2009, RoundCube Dev. - Switzerland                 |
+ | Licensed under the GNU GPL                                            |
+ |                                                                       |
+ | PURPOSE:                                                              |
+ |   Provide database supported session management                       |
+ |                                                                       |
+ +-----------------------------------------------------------------------+
+ | Author: Thomas Bruederli <roundcube@gmail.com>                        |
+ | Author: Aleksander Machniak <alec@alec.pl>                            |
+ +-----------------------------------------------------------------------+
+
+ $Id: session.inc 2932 2009-09-07 12:51:21Z alec $
+
+*/
+
+class rcube_session
+{
+  private $db;
+  private $ip;
+  private $changed;
+  private $unsets = array();
+  private $gc_handlers = array();
+  private $start;
+  private $vars = false;
+  private $key;
+  private $keep_alive = 0;
+
+  /**
+   * Default constructor
+   */
+  public function __construct($db, $lifetime=60)
+  {
+    $this->db = $db;
+    $this->lifetime = $lifetime;
+    $this->start = microtime(true);
+
+    // set custom functions for PHP session management
+    session_set_save_handler(
+      array($this, 'open'),
+      array($this, 'close'),
+      array($this, 'read'),
+      array($this, 'write'),
+      array($this, 'destroy'),
+      array($this, 'gc'));
+  }
+
+
+  public function open($save_path, $session_name)
+  {
+    return true;
+  }
+
+
+  public function close()
+  {
+    return true;
+  }
+
+
+  // read session data
+  public function read($key)
+  {
+    $sql_result = $this->db->query(
+      sprintf("SELECT vars, ip, %s AS changed FROM %s WHERE sess_id = ?",
+        $this->db->unixtimestamp('changed'), get_table_name('session')),
+      $key);
+
+    if ($sql_arr = $this->db->fetch_assoc($sql_result)) {
+      $this->changed = $sql_arr['changed'];
+      $this->vars = $sql_arr['vars'];
+      $this->ip = $sql_arr['ip'];
+      $this->key = $key; 
+
+      if (!empty($sql_arr['vars']))
+        return $sql_arr['vars'];
+    }
+
+    return false;
+  }
+  
+
+  // save session data
+  public function write($key, $vars)
+  {
+    $ts = microtime(true);
+    $now = $this->db->fromunixtime((int)$ts);
+
+    // use internal data from read() for fast requests (up to 0.5 sec.)
+    if ($key == $this->key && $ts - $this->start < 0.5) {
+      $oldvars = $this->vars;
+    } else { // else read data again from DB
+      $oldvars = $this->read($key);
+    }
+    
+    if ($oldvars !== false) {
+      $a_oldvars = $this->unserialize($oldvars); 
+      foreach ((array)$this->unsets as $k)
+        unset($a_oldvars[$k]);
+
+      $newvars = $this->serialize(array_merge(
+        (array)$a_oldvars, (array)$this->unserialize($vars)));
+
+      if ($this->keep_alive>0) {
+	$timeout = min($this->lifetime * 0.5, 
+		       $this->lifetime - $this->keep_alive);
+      } else {
+	$timeout = 0;
+      }
+
+      if (!($newvars === $oldvars) || ($ts - $this->changed > $timeout)) {
+        $this->db->query(
+	  sprintf("UPDATE %s SET vars = ?, changed = %s WHERE sess_id = ?",
+	    get_table_name('session'), $now),
+	  $newvars, $key);
+      }
+    }
+    else {
+      $this->db->query(
+        sprintf("INSERT INTO %s (sess_id, vars, ip, created, changed) ".
+          "VALUES (?, ?, ?, %s, %s)",
+	  get_table_name('session'), $now, $now),
+        $key, $vars, (string)$_SERVER['REMOTE_ADDR']);
+    }
+
+    $this->unsets = array();
+    return true;
+  }
+
+
+  // handler for session_destroy()
+  public function destroy($key)
+  {
+    $this->db->query(
+      sprintf("DELETE FROM %s WHERE sess_id = ?", get_table_name('session')),
+      $key);
+
+    return true;
+  }
+
+
+  // garbage collecting function
+  public function gc($maxlifetime)
+  {
+    // just delete all expired sessions
+    $this->db->query(
+      sprintf("DELETE FROM %s WHERE changed < %s",
+        get_table_name('session'), $this->db->fromunixtime(time() - $maxlifetime)));
+
+    foreach ($this->gc_handlers as $fct)
+      $fct();
+
+    return true;
+  }
+
+
+  // registering additional garbage collector functions
+  public function register_gc_handler($func_name)
+  {
+    if ($func_name && !in_array($func_name, $this->gc_handlers))
+      $this->gc_handlers[] = $func_name;
+  }
+
+
+  public function regenerate_id()
+  {
+    $randval = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
+
+    for ($random = '', $i=1; $i <= 32; $i++) {
+      $random .= substr($randval, mt_rand(0,(strlen($randval) - 1)), 1);
+    }
+
+    // use md5 value for id or remove capitals from string $randval
+    $random = md5($random);
+
+    // delete old session record
+    $this->destroy(session_id());
+
+    session_id($random);
+
+    $cookie   = session_get_cookie_params();
+    $lifetime = $cookie['lifetime'] ? time() + $cookie['lifetime'] : 0;
+
+    rcmail::setcookie(session_name(), $random, $lifetime);
+
+    return true;
+  }
+
+
+  // unset session variable
+  public function remove($var=NULL)
+  {
+    if (empty($var))
+      return $this->destroy(session_id());
+
+    $this->unsets[] = $var;
+    unset($_SESSION[$var]);
+
+    return true;
+  }
+
+
+  // serialize session data
+  private function serialize($vars)
+  {
+    $data = '';
+    if (is_array($vars))
+      foreach ($vars as $var=>$value)
+        $data .= $var.'|'.serialize($value);
+    else
+      $data = 'b:0;';
+    return $data;
+  }
+
+
+  // unserialize session data
+  // http://www.php.net/manual/en/function.session-decode.php#56106
+  private function unserialize($str)
+  {
+    $str = (string)$str;
+    $endptr = strlen($str);
+    $p = 0;
+
+    $serialized = '';
+    $items = 0;
+    $level = 0;
+
+    while ($p < $endptr) {
+      $q = $p;
+      while ($str[$q] != '|')
+        if (++$q >= $endptr) break 2;
+
+      if ($str[$p] == '!') {
+        $p++;
+        $has_value = false;
+      } else {
+        $has_value = true;
+      }
+
+      $name = substr($str, $p, $q - $p);
+      $q++;
+
+      $serialized .= 's:' . strlen($name) . ':"' . $name . '";';
+
+      if ($has_value) {
+        for (;;) {
+          $p = $q;
+          switch (strtolower($str[$q])) {
+            case 'n': /* null */
+            case 'b': /* boolean */
+            case 'i': /* integer */
+            case 'd': /* decimal */
+              do $q++;
+              while ( ($q < $endptr) && ($str[$q] != ';') );
+              $q++;
+              $serialized .= substr($str, $p, $q - $p);
+              if ($level == 0) break 2;
+              break;
+            case 'r': /* reference  */
+              $q+= 2;
+              for ($id = ''; ($q < $endptr) && ($str[$q] != ';'); $q++) $id .= $str[$q];
+              $q++;
+              $serialized .= 'R:' . ($id + 1) . ';'; /* increment pointer because of outer array */
+              if ($level == 0) break 2;
+              break;
+            case 's': /* string */
+              $q+=2;
+              for ($length=''; ($q < $endptr) && ($str[$q] != ':'); $q++) $length .= $str[$q];
+              $q+=2;
+              $q+= (int)$length + 2;
+              $serialized .= substr($str, $p, $q - $p);
+              if ($level == 0) break 2;
+              break;
+            case 'a': /* array */
+            case 'o': /* object */
+              do $q++;
+              while ( ($q < $endptr) && ($str[$q] != '{') );
+              $q++;
+              $level++;
+              $serialized .= substr($str, $p, $q - $p);
+              break;
+            case '}': /* end of array|object */
+              $q++;
+              $serialized .= substr($str, $p, $q - $p);
+              if (--$level == 0) break 2;
+              break;
+            default:
+              return false;
+          }
+        }
+      } else {
+        $serialized .= 'N;';
+        $q += 2;
+      }
+      $items++;
+      $p = $q;
+    }
+
+    return unserialize( 'a:' . $items . ':{' . $serialized . '}' );
+  }
+
+  public function set_keep_alive($keep_alive)
+  {
+    $this->keep_alive = $keep_alive;
+  }
+
+  public function get_keep_alive()
+  {
+    return $this->keep_alive;
+  }
+
+  // getter for private variables
+  public function get_ts()
+  {
+    return $this->changed;
+  }
+
+  // getter for private variables
+  public function get_ip()
+  {
+    return $this->ip;
+  }
+
+}