What's wrong with this PHP class constant declaration?

Question

What's wrong with this code?

   <?php
    namespace DEMO;
    
    class Config
    {
        const PRICE = $_GET['alim'];
    }

Why I'm getting Error 500 for using $_GET['alim'] but If I use const PRICE = '100'; then It's Ok

Because it is a const which is defined prior to $_GET being available. — Alex Barker, Nov 06 '20 at 16:33
This is NOT a *Get Method* like you wrote in the title, it is a class constant. — Lorenz Meyer, Nov 06 '20 at 16:34
Do not do this. If you do this that means you need to have the `alim` parameter set on every single web request you receive otherwise this code will break — apokryfos, Nov 06 '20 at 16:37

Lorenz Meyer · Answer 1 · 2020-11-06T16:41:29.247

2

You can use only constant expressions in class constant definitions. You have to affect the value to Config::price in the constructor.

<?php
namespace DEMO;

class Config
{
    private $price;
    public function __construct()
    {
        $this->price = $_GET['alim'];
    }
}

edited Nov 06 '20 at 16:41

answered Nov 06 '20 at 16:38

Lorenz Meyer

1

I would suggest not using `$_GET` directly within a class, as opposed to using proper DI. – Jeto Nov 06 '20 at 16:40
1

@Jeto Thanks, I published too fast. – Lorenz Meyer Nov 06 '20 at 16:42

1 Answers1