Type mime not specified

Question

I am currently creating a PHP application that allows users to upload files. I am on the download page, but my verification system is not working. I use this system to check files as audio files.

// Set our file name and extension $fname = $_FILES['file']['name']; $extension = strtolower(substr($fname, strpos($fname, '.') + 1)); // Check file if ($extension == 'mp3' && $_FILES['file']['type'] == 'audio/mpeg') { //File is valid mp3 } else { //File is invalid } 

Now this does not work, but it is strange when I echo from $_FILES['file']['type'] , it does not output the mime type for audio files. When I do this for any other type of file, it successfully drives it away.

It does not give the mime type only for audio files. I tried it with WAV and M4A files, and it does not return with any of them. Is this something with the file type, or do I need to edit the .htaccess file or the MIME.types file on my xampp server. Could there also be a better way to check downloaded files?

Also note that this is done on my xampp server and on a free server that I use for testing.

Thanks for the help.

Answer 1

$_FILES['file']['type'] comes from the browser that downloads the file, so you cannot fully rely on this value.

Check out finfo_file for identifying file types based on file contents. The file extension is also unreliable, since the user can download malicious code with the mp3 extension.