A piece of php code that detects the file type (based on the file header)

//Detect file type
$filename = "11.jpg";
//Picture path
$file = fopen ($filename, "rb");
$bin = fread($file, 2); //Read only 2 bytes
fclose($file);
$strInfo = @unpack ("C2chars", $bin);
$typeCode = intval($strInfo['chars1'].$strInfo['chars2']);
$fileType = '';
switch ($typeCode) {
case 7790: $fileType = 'exe'; break;
case 7784: $fileType = 'midi'; break;
case 8297: $fileType = 'rar'; break;
case 255216: $fileType = 'jpg'; break;
case 7173: $fileType = 'gif'; break;
case 6677: $fileType = 'bmp'; break;
case 13780: $fileType = 'png'; break;
default: echo 'unknown';
}
echo'This is a '.$fileType.' file:'.$typeCode;
//Judge file under linux Type function mime_content_type
//This function is also good
echo mime_content_type('test1.gif') . "n";
echo mime_content_type('test2.php');
?>