Using a variable value when defining in PHP

Question

$product_id_string = $_GET['product_id'];
$product_id = (int)$product_id_string;


//this should be derived from GET or the method you use to distinguish entities
define('ENTITY_ID', $product_id);

The above code is part of a plugin that I am attempting to modify - If I change $product_id to a number, the code works - however when I try to GET the product_id, a 0 ends up being saved to the database instead of the GET variable.

Example of working code:

define('ENTITY_ID', 2547);

If I echo the $product_id, I receive the number I want.

$product_id_string = $_GET['product_id'];
$product_id = (int)$product_id_string;
echo $product_id; //Returns 2547
define('ENTITY_ID', $product_id); //Ends up saving as 0 in database

Answer 1

Use the below statement to convert to int. That will fix the issue

$product_id = intval($product_id_string);