PHP implementation code for reading file headers to determine file type_PHP tutorial

//For the path of the picture, you can use absolute paths such as d:/upload/11.jpg
$file = fopen($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;

?>
//There is also a function in php under Linux that can determine the file type
echo mime_content_type('11.gif') . "n";
echo mime_content_type('22.php');
?>