Testing IPN for paypal

Had trouble on getting return for IPN for paypal so here are the code that might help
So I created a var_dump POST to error log and wrote it down to a text file.
tried error_log($_POST) but it doesn’t work…

There’s this test tool from paypal sandbox which might help it test the post
https://developer.paypal.com/us/cgi-bin/devscr


[code type=codetype]
ob_start();
var_dump($_POST);
$c = ob_get_contents();
ob_end_clean();
$fp = fopen(“static/log/paypal_notify.txt”, “a”);
fwrite($fp, $c);
fclose($fp);
error_log($c);
exit();
[/code]

Another Method on getting post or get is
error_log(print_r($_POST, true));
error_log(print_r($_GET, true));