PHP takes binary file header and quickly determines file type_PHP tutorial

Generally, we judge the file type based on the file extension, but this is very unreliable and can be easily avoided by changing the extension. Generally, the file information must be read to identify it.

$files = array('./test.jpg', 'test.png');
$fileTypes = array(
7790 => 'exe',
7784 => 'midi',
8075 => 'zip',
8297 => 'rar',
225216 => 'jpg',
7173 => 'gif',
6677 => 'bmp',
13780 => 'png',
);
foreach($files as $file) {
$fp = fopen($file, 'rb');
$bin = fread($fp, 2); // Read only the first two bytes
fclose($fp);
$strInfo = @unpack("C2chars", $bin);
$typeCode = intval($strInfo['chars1'].$strInfo['chars2']);
$fileType = isset($fileTypes[$typeCode]) ? $fileTypes[$typeCode] : 'unknown';
echo $file , ' type : ', $fileType, ' code : ', $fileType, '
';
}

http://www.bkjia.com/PHPjc/477942.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/477942.htmlTechArticleGenerally we judge the file type based on the file extension, but this is very unreliable and can be easily modified To avoid the extension, generally the file information must be read to identify it. ...