Linux下Web服务基于数据库的会话管理

CREATE DATABASE sessions
CREATE TABLE sessions ( sesskey char(32) PRIMARY KEY,
                          expiry int NOT NULL,
                         alue text NOT NULL)

<?php
require_once("DB.php");
$SESS_DBHOST = "localhost";    /*数据库服务器主机名*/
$SESS_DBNAME = "sessions";     /* 数据库名 */
$SESS_DBUSER = "kycman";       /* 数据库用户 */
$SESS_DBPASS = "kycman";       /* 数据库口令 */
$SESS_DBH = "";
$SESS_LIFE = get_cfg_var("session.gc_maxlifetime");
function sess_open($save_path, $session_name) {
global $SESS_DBHOST, $SESS_DBNAME, $SESS_DBUSER, $SESS_DBPASS, $SESS_DBH;
$dns="pgsql://$SESS_DBUSER:$SESS_DBPASS@$SESS_DBHOST/$SESS_DBNAME";
$SESS_DBH=DB::connect($dns);
        if (DB::isError($SESS_DBH)) {
                die($SESS_DBH->getMessage());
        }
        return true;
}
function sess_close() {
        $SESS_DBH->disconnect();
        return true;
}
function sess_read($key) {
        global $SESS_DBH, $SESS_LIFE;
        $qry = "SELECT value FROM sessions 
WHERE sesskey = '$key' AND expiry > " . time();
        $qid = $SESS_DBH->query($qry);
        if (list($value) = $qid->fetchRow()) {
                return $value;
        }
        return false;
}
function sess_write($key, $val) {
        global $SESS_DBH, $SESS_LIFE;
        $expiry = time() + $SESS_LIFE;
        $value = addslashes($val);
        $qry = "INSERT INTO sessions VALUES ('$key', $expiry, '$value')";
        $qid = $SESS_DBH->query($qry);
        if (!DB::isError($qid)) {
                $qry = "UPDATE sessions SET expiry = $expiry, 
value = '$value' WHERE sesskey = '$key' AND expiry > " . time();
                $qid = $SESS_DBH->query($qry);
        }
        return $qid;
}
function sess_destroy($key) {
        global $SESS_DBH;
        $qry = "DELETE FROM sessions WHERE sesskey = '$key'";
        $qid = $SESS_DBH->query($qry);
        return $qid;
}
function sess_gc($maxlifetime) {
        global $SESS_DBH;
        $qry = "DELETE FROM sessions WHERE expiry < " . time();
        $qid = $SESS_DBH->query($qry);
        return $SESS_DBH->affectedRows();
}
session_set_save_handler("sess_open","sess_close",
"sess_read","sess_write",
                         "sess_destroy","sess_gc");
?>