Problem on checking valid file name ~

[waimichael]

I am going to validate the file name (either on UNIX, Linux or Windows) which the user input from the HTML textfield element and sent to .php using POST method. However, I have no idea how to check whether it validates or not. Would someone help me on this problem? Thanks a lot.

[rohithmr]

First you have kno which characters are allowed in a filename. In windows a filename cannot have any of \/*😐?><.

so a sample code will be:

<?php 
function chkFileName($filename) {
 return (strlen($filename) == strcspn($filename,'\\/*?:<>|')); 
}

// remember to escape \ with \\ before passing it to the function.
// cuz a \ at the end of the filename will cause parse errors.

if (chkFileName('valid_filename')) {
 echo 'Filename is valid';
} else {
 echo 'Filename is not valid';
 }
?>