"expects parameter 1 to be a valid path, string given"

Question

I think I may have a Heisenbug on my hands. My code so far looks like this:

$enc = $_REQUEST['l'];
$filename = DecryptString($enc);

echo $filename;  //Displays: uploads/Maid with the Flaxen Hair.mp3


if (is_dir($filename))  //Gives the error: "Warning: is_dir() expects parameter 1 to be a valid path, string given"
{

    Download($filename);
}

However, if I take what as echo'ed earlier, which was uploads/Maid with the Flaxen Hair.mp3, and run is_dir("uploads/Maid with the Flaxen Hair.mp3"), it returns as expected.

So if I pass the variable into is_dir, it fails, but if I pass the value of the variable it works. What's the catch?

Answer 1

DecryptString() is returning a string with NULs (\0) at the end.

Make sure you trim them off before trying to use the value.

You can trim the NULL character with $enc = trim($enc);