PHP sessions and class members - php

Question

Ok, messing about with classes in PHP and can't get it to work the way I'm used to as a C++/Java-guy. In the "_init" function, if I run a query at the "// query works here" line", everythong works, but in the "getUserID" function, all that happens is said warning...
"getUserID" gets called from login.php (they are in the same dir):
login.php
<?php
include_once 'sitehandler.php';
include_once 'dbhandler.php';
session_start();
#TODO: Safer input handling
$t_userName = $_POST["name"];
$t_userId = $_SESSION['handler']['db']->getUserID($t_userName);
if ($t_userId != -1) {
$_SESSION['user']['name'] = $t_userName;
$_SESSION['user']['id'] = $t_userId;
}
//error_log("user: " . $_SESSION['user']['name'] . ", id: ". $_SESSION['user']['id']);
header("Location: " . $_SERVER["HTTP_REFERER"]);
?>
dbhandler.php
<?php
include_once 'handler.php';
class DBHandler extends HandlerAbstract {
private $m_handle;
function __construct() {
parent::__construct();
}
public function test() {
#TODO: isdir liquibase
#TODO: isfile liquibase-195/liquibase + .bat + execrights
$this->m_isTested = true;
}
public function _init() {
if (!$this->isTested()) $this->test();
if (!file_exists('files/data.db')) {
#TODO: How to to if host is Windows based?
exec('./files/liquibase-1.9.5/liquibase --driver=org.sqlite.JDBC --changeLogFile=files/data_db.xml --url=jdbc:sqlite:files/data.db update');
#TODO: quit if not success
}
#TODO: Set with default data
try {
$this->m_handle = new SQLite3('files/data.db');
} catch (Exception $e) {
die("<hr />" . $e->getMessage() . "<hr />");
}
// query works here
$this->m_isSetup = true;
}
public function teardown() {
}
public function getUserID($name) {
// PHP Warning: SQLite3::prepare(): The SQLite3 object has not been correctly initialised in
$t_statement = $this->m_handle->prepare("SELECT id FROM users WHERE name = :name");
$t_statement->bindValue(":name", $name, SQLITE3_TEXT);
$t_result = $t_statement->execute();
//var_dump($this->m_handle);
return ($t_result)? (int)$t_result['id']: -1;
}
}

Answer 1

When you place something in the session and the script ends, PHP goes through each object and calls the __sleep() magic function. Once it resumes the session, __wakeup() is called.
Resources are not stored in sessions. So every time you want to have a resource available to you, you must initialize it on every script run. This can easily be done, in your example, by implementing the __wakeup() magic method, which should call $this->_init();.
Your code could then become:
<?php
include_once 'handler.php';
class DBHandler extends HandlerAbstract { private $m_handle;
function __construct() {
parent::__construct();
}
public function test() {
#TODO: isdir liquibase
#TODO: isfile liquibase-195/liquibase + .bat + execrights
$this->m_isTested = true;
}
public function _init() {
if (!$this->isTested()) $this->test();
if (!file_exists('files/data.db')) {
#TODO: How to to if host is Windows based?
exec('./files/liquibase-1.9.5/liquibase --driver=org.sqlite.JDBC --changeLogFile=files/data_db.xml --url=jdbc:sqlite:files/data.db update');
#TODO: quit if not success
}
#TODO: Set with default data
try {
$this->m_handle = new SQLite3('files/data.db');
} catch (Exception $e) {
die("<hr />" . $e->getMessage() . "<hr />");
}
// query works here
$this->m_isSetup = true;
}
public function teardown() {
}
public function getUserID($name) {
// PHP Warning: SQLite3::prepare(): The SQLite3 object has not been correctly initialised in
$t_statement = $this->m_handle->prepare("SELECT id FROM users WHERE name = :name");
$t_statement->bindValue(":name", $name, SQLITE3_TEXT);
$t_result = $t_statement->execute();
//var_dump($this->m_handle);
return ($t_result)? (int)$t_result['id']: -1;
}
/**
* Start up the SQLite resource once
* the session is started.
*
*/
public function __wakeup() {
$this->init();
}
}