PHP mandatory file download function code of arbitrary file format

 
 
function force_download($file) 
{ 
if ((isset($file))&&(file_exists($file))) { 
header("Content-length: ".filesize($file)); 
header('Content-Type: application/octet-stream'); 
header('Content-Disposition: attachment; filename="' . $file . '"'); 
readfile("$file"); 
} else { 
echo "No file selected"; 
} 
} 

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