如何使用PHP从URL获取特殊字符？ 如％20

Lets say I have this in my URL;

/?utmsource=John%20Kez

I need to get 'John%20Kez' exactly as it is, with %20 not a space. I have tried;

echo $_GET['utmsource'];
echo htmlspecialchars_decode($_GET['utmsource']);
echo htmlspecialchars($_GET['utmsource']);

All of them return 'John Kez'. How can I return 'John%20Kez'?

You can use rawurlencode():

echo rawurlencode($_GET['utmsource']);