How to Access Data from One Class in multiple Children Classes - php

Question

I'm having a bit of trouble in designing my classes in php.
As you can see in my Code, i want to have one Class instance and having more classes as children which "talk" from one to another. im getting the logged user and get all his information stored to a variable. In my other Classes i recently need to get this UserData.
Any help and Ideas are welcome :)
class Factory
{
private $UserData;
public function Factory()
{
DB::connect();
$this->getLoggedUserData( $_SERVER['REMOTE_USER'] );
}
private function getLoggedUserData( $user )
{
$result = DB::query( "SELECT * FROM users WHERE user='$user' LIMIT 1" );
$this->UserData = $result->fetch_assoc();
}
public function getMyTasks()
{
// how to call that class, without instancing it over and over again
MyOtherClass -> getMyTasks();
}
}
class MyOtherClass
{
public function getMyTasks()
{
// how to access the "global" variable
$result = DB::query( "SELECT * FROM tasks WHERE userID=" . $UserData['userID'] . " LIMIT 1" );
// doSomething ($result);
}
}
class DB
{
private static $mysqli;
public static function connect()
{
$mysqli = new mysqli(MYSQL_SERVER, MYSQL_USER, MYSQL_PASSWORD, MYSQL_DB);
if ($mysqli->connect_error) {
die('Connect Error (' . $mysqli->conect_errno . ')' . $mysqli->connect_error);
}
mysqli_set_charset($mysqli, 'utf8');
self::$mysqli = $mysqli;
}
public static function query( $query )
{
$result = self::$mysqli->query( $query );
if ( self::$mysqli->error ) {
error_log("QUERY ERROR: " . self::$mysqli->error);
error_log("QUERY: " . $query);
}
return $result;
}
}
$Factory = new Factory();

Answer 1

OK, here goes a simple trivial approach to your problem
Mind you, this is not complete. Gimme some feedback if this is closing in on what you'd expect
your classes changed a bit
<?php
class Factory {
private $UserData;
private $UserTask;
public function Factory() {
DB::connect();
$this->getLoggedUserData($_SERVER['REMOTE_USER']);
}
private function getLoggedUserData($user) {
$result = DB::query('SELECT * FROM users WHERE user="'.$user.'" LIMIT 1');
$this->UserData = $result->fetch_assoc();
}
public function getMyTasks() {
// how to call that class, without instancing it over and over again
if (!isset($this->UserTask)) $this->UserTask = new MyOtherClass($this->UserData);
return $this->UserTask->getMyTasks();
}
}
class MyOtherClass {
private $UserData;
public function __construct($userData) {
$this->userData = $userData;
}
public function getMyTasks() {
// how to access the "global" variable
$task = DB::query('SELECT * FROM tasks WHERE userID='.$this->UserData['userID'].' LIMIT 1');
return $this->performTask($task);
}
public function performTask($task) {/* doSomething(); */}
}
// usage is not complete, waiting for some extra input
$factory = new Factory();
$taskResults = $factory->getMyTasks();
Any input on how to improve this is very welcome
edit following comments
Let's take a look at how you can solve the problem of having to share instances between different "apps" in your code
the singleton approach: an instance is created on the first call, all subsequent calls are passed the single instance
the registry pattern: an object created at the start of the script picks up all initialized requirements and stores them. If any "app" needs the basic set of services (it's not standalone), then pass the registry object to it's initializer/constructor.
I hope I understood your comments well enough, if not feel free to ask and correct me

Answer 2

Hard to say what would be best for you when i dont know more about the scale of your application etc.
Anyway the simplest way is something like this:
$otherClass = new MyOtherClass();
$Factory = new Factory($otherClass);
Class Factory
class Factory
{
private $UserData;
private someClass;
public function Factory(&$someClass)
{
$this->someClass = $someClass;
DB::connect();
$this->getLoggedUserData( $_SERVER['REMOTE_USER'] );
}
...
Usage
$this->someClass->getMyTasks();
But in case you only want access to the methods/variables of the parent, then yes extend the class.