My_Session_SaveHandler_DbTable.php

<?php

class My_Session_SaveHandler_DbTable extends Zend_Session_SaveHandler_DbTable
{
    /**
     * Read session data
     *
     * @param string $id
     * @return string
     */
    public function read($id)
    {
        $return = '';

        $db = $this->getAdapter();
        $select_stmt = $db->prepare('SELECT * FROM ' . $this->_name . ' WHERE id = ?');
        $select_stmt->execute(array($id));

        $select_stmt->bindColumn(1, $id, PDO::PARAM_STR);
        $select_stmt->bindColumn(2, $modified, PDO::PARAM_INT);
        $select_stmt->bindColumn(3, $lifetime, PDO::PARAM_INT);
        $select_stmt->bindColumn(4, $data, PDO::PARAM_STR);  //  bytea を stringとして扱う
        $result = $select_stmt->fetch(PDO::FETCH_BOUND);

        if ($result === true) {
            $expirationtime = (int)$modified + (int)$lifetime;
            if ($expirationtime > time()) {
                $return = pg_unescape_bytea($data);
            } else {
                $this->destroy($id);
            }
        }

        return $return;
    }

    /**
     * Write session data
     *
     * @param string $id
     * @param string $data
     * @return boolean
     */
    public function write($id, $data)
    {
        $return = false;
        $nowtime = time();
        $data = pg_escape_bytea((string)$data);

        $rows = call_user_func_array(array(&$this, 'find'), $this->_getPrimary($id));
        $db = $this->getAdapter();

        if (count($rows)) {
            $lifetime = $this->_getLifetime($rows->current());

            $update_stmt = $db->prepare('UPDATE ' . $this->_name 
                                     . ' SET ' . $this->_modifiedColumn
                                     . ' = ?, ' . $this->_lifetimeColumn
                                     . ' = ?, ' . $this->_dataColumn 
                                     . ' = ? '
                                     . ' WHERE id = ?' 
                           );


            $update_stmt->bindParam(1, $nowtime, PDO::PARAM_INT);
            $update_stmt->bindParam(2, $lifetime, PDO::PARAM_INT);
            //   bytea を string として扱う
            $update_stmt->bindParam(3, $data, PDO::PARAM_STR);
            $update_stmt->bindParam(4, $id, PDO::PARAM_STR);
            $update_stmt->execute();
            $return = true;

        } else {

            $insert_stmt = $db->prepare('INSERT INTO ' . $this->_name . ' VALUES (?, ?, ?, ?)');
            $insert_stmt->bindParam(1, $id, PDO::PARAM_STR);
            $insert_stmt->bindParam(2, $nowtime, PDO::PARAM_INT);
            $insert_stmt->bindParam(3, $this->_lifetime, PDO::PARAM_INT);
            //   bytea を string として扱う
            $insert_stmt->bindParam(4, $data, PDO::PARAM_STR);

            $insert_stmt->execute();
            $return = true;
        }

        return $return;
    }

}