Error with this PHP config file

Question

Hello I'm trying to make a simple configuration file for my app my project folder is: inside folder 'app' -Config.php inside root directory: -index.php -config.php

this is how config.php looks like:

<?php  
return [
    'db' => [
        'hosts' => [
            'local' => 'localhost',
            'externo' => '1.1.1.1',
        ],
        'name' => 'db-stats',
        'user' => 'root',
        'password' => 'root'
    ],
    'mail' => [
        'host' => 'smtp.gmail.com'
    ]
];

?>

Config.php is:

<?php 
namespace Project\Helpers;
class Config
{
    protected $data;
    protected $default = null;
    public function load($file){
        $this->$data = require $file;
    }
    public function get($key, $default = null){
        $this->$default = $default;
        $segments = explode('.', $key);
        $data = $this->$data;

        foreach ($segments as $segment) {
            if(isset($data[$segment])){
                $data = $data[$segment];
            }else{
                $data = $this->$default;
                break;
            }
        }
        return $data;
    }
    public function exists($key){
        return $this->get($key) !== $this->$default;
    }
}
?>

and finally index.php:

<?php 

use Project\Helpers\Config;
require 'app/Config.php';

$config = new Config;
$config->load('config.php');

echo $config->get('db.hosts.local');

?>

the thing is I'm getting this 2 errors when I run the page:

Notice: Undefined variable: data in C:\\xampp\\htdocs\\probar\\app\\Config.php on line 11

Fatal error: Cannot access empty property in C:\\xampp\\htdocs\\probar\\app\\Config.php on line 11

please help me what's is wrong with this???

Answer 1

$this->data = require $file; not $this->$data = require $file; .

And $this->default = $default; instead of $this->$default = $default;

Otherwise those would be variable variables .

<?php 
namespace Project\Helpers;
class Config
{
    protected $data;
    protected $default = null;
    public function load($file){
        $this->data = require $file;
    }
    public function get($key, $default = null){
        $this->default = $default;
        $segments = explode('.', $key);
        $data = $this->data;

        foreach ($segments as $segment) {
            if(isset($data[$segment])){
                $data = $data[$segment];
            }else{
                $data = $this->default;
                break;
            }
        }
        return $data;
    }
    public function exists($key){
        return $this->get($key) !== $this->default;
    }
}

Answer 2

You have a synthax error in the class constructor. In PHP, when you access a member attribute with the -> operator, you don't have to use the $ modifier.

The correct code looks like this:

<?php
namespace Project\Helpers;
class Config
{
    protected $data;
    protected $default = null;
    public function load($file){
        $this->data = require $file;
    }
    public function get($key, $default = null){
        $this->default = $default;
        $segments = explode('.', $key);
        $data = $this->data;

        foreach ($segments as $segment) {
            if(isset($data[$segment])){
                $data = $data[$segment];
            }else{
                $data = $this->default;
                break;
            }
        }
        return $data;
    }
    public function exists($key){
        return $this->get($key) !== $this->default;
    }
}