Refine String for Filename

[ravix76]

I have a user inputted string which I which to refine for use as a filename. The string might include special characters such as £ % etc which I want to strip out or substitute. I'll then convert to lowercases, append a file extension and use it for the uploaded file / image.

 

I having difficulty making the string safe for filename use.

I essentially want to strip out any non a-z or 0-9 characters and strip out any spaces (or substitute with a dash).

 

So  "CrazyDave's Upload!" would become "crazydaves-upload.jpg"

 

Do I need regular expressions? <-- seems like a deep topic!

 

Thanks

[PHPTOM]

<?PHP
function validFileName($text, $extension = 'jpg'){
return ereg_replace("[^A-Za-z0-9\-]", "", str_replace(' ', '-', strtolower(trim($text)))).'.'.$extension;
}

echo validFileName("CrazyDave's Upload!");
?>