Unable to use PDO methods when using DB class - php

Question

Hey guys I'm doing this wrong again I'm sure, but I'm trying to instantiate a PDO database
handler from my class Database from the file class.database.php inside my class AdminSession
from class.admin.php, somethings a bit screwy with my dependancy injection, and it is not
allowing me to use PDO's methods corretly; like fetch(), prepare() etcetra.
the class.database.php file
class Database
{
public $db; // handle of the db connection
private static $dsn="mysql:host=server2.com;dbname=database";
private static $user="user";
private static $pass="pass";
private static $instance;
public function __construct ()
{
$this->db = new PDO(self::$dsn,self::$user,self::$pass,$self::$opts);
$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$this->db->setAttribute(PDO::MYSQL_ATTR_INIT_COMMAND, "SET NAMES 'utf8'");
switch($_SERVER['ENVIRONMENT']) {
case 'staging':
self::$dsn="mysql:host=server1.com;dbname=database";
self::$user="user";
self::$pass="pass";
break;
default:
self::$dsn="mysql:host=server2.com;dbname=database";
self::$user="user";
self::$pass="pass";
}
}
public static function getInstance()
{
if(!isset(self::$instance))
{
$object= __CLASS__;
self::$instance=new $object;
}
return self::$instance;
}
}
and here's the topmost of my class.admin.php, and a method that is throwing an error.
right now the errors I'm getting
PHP Fatal error: Call to undefined method line 230
If I use $this->db-prepare($sql)
or
PHP Fatal error: Call to a member function prepare() on a non-object line 230
If I use $db-prepare($sql)
require('library/class.database.php');
class AdminSession {
static $abs_path;
public function __construct(Database $db) {
session_start();
self::$abs_path = dirname(dirname(__FILE__));
if($_SERVER['REQUEST_METHOD'] == 'POST') {
$this->post = $_POST; // filter_input_array(INPUT_POST, FILTER_SANITIZE_STRING);
if(get_magic_quotes_gpc ()) {
//get rid of magic quotes and slashes if present
array_walk_recursive($this->post, array($this, 'stripslash_gpc'));
}
}
$this->get = $_GET; // filter_input_array(INPUT_GET, FILTER_SANITIZE_STRING);
array_walk_recursive($this->get, array($this, 'urldecode'));
}
// other methods
private function checkDB($username, $password) {
$sql = "SELECT * FROM users WHERE username=:username";
try {
$db = Database::getInstance();
$stmt = $db->prepare($sql);
$stmt->bindParam("username", $username);
$stmt->execute();
$user = $stmt->fetchAll(PDO::FETCH_OBJ);
$db = null;
if($user) {
//general return
if(is_object($user[0]) && md5($user[0]->password) == $password) {
return true;
} else {
return false;
}
} else {
return false;
}
} catch(PDOException $e) {
echo '{"error":{"text":'. $e->getMessage() .'}}';
}
}
}

Answer 1

You can't put logic into your class definition. Instead, determine the value of these variables within the constructor. The switch will work in a method, but not when defining members.
Edit: I actually feel silly for missing this. The connection was made before the switch statement. I don't know that it'll fix the second set of issues ... but it'll behave properly for the original question now.
class Database
{
public $db; // handle of the db connection
private static $opts = array(PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES utf8');
private static $dsn="mysql:host=server2.com;dbname=database";
private static $user="user";
private static $pass="pass";
private static $instance;
public function __construct ()
{
switch($_SERVER['ENVIRONMENT']) {
case 'staging':
self::$dsn="mysql:host=server1.com;dbname=database";
self::$user="user";
self::$pass="pass";
break;
default:
self::$dsn="mysql:host=server2.com;dbname=database";
self::$user="user";
self::$pass="pass";
}
$this->db = new PDO(self::$dsn,self::$user,self::$pass,$self::$opts);
$this->db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
}
public static function getInstance()
{
if(!isset(self::$instance))
{
$object= __CLASS__;
self::$instance=new $object;
}
return self::$instance;
}
}