PHP detects file type (based on file header information)_PHP tutorial

The article provides a PHP file type detection method (based on file header information). It can confirm the file type based on the file header information posted by the user.

The article provides a PHP tutorial to detect file types (based on file header information). It can determine the file type based on the file header information posted by the user.

/*Get the file type through the file name*
*@author chengmo*
*@copyright cnblog.com/chengmo 2010-10-17
*@version 0.1
*$filename="d:/1.png";echo cfiletypecheck::getfiletype($filename); print: png
*/
class cfiletypecheck
{
private static $_typelist=array();
private static $checkclass=null;
private function __construct($filename)
{
self::$_typelist=$this->gettypelist() ;
}
/**
*Process file type mapping table*
*
* @param string $filename file type
* @return string file type, not found return: other
*/
private function _getfiletype($filename)
{
$filetype="other";
if(!file_exists($filename )) throw new exception("no found file!");
$file = @fopen($filename,"rb");
if(!$file) throw new exception("file refuse!") ;
$bin = fread($file, 15); //Only 15 bytes are read for different file types, and the header information is different.
fclose($file);
$typelist=self::$_typelist;
foreach ($typelist as $v)
{
$blen=strlen(pack("h*" ,$v[0])); //Get the number of bytes marked in the file header
$tbin=substr($bin,0,intval($blen)); ///Need to compare the file header length
if (strtolower($v[0])==strtolower(array_shift(unpack("h*",$tbin))))
{
return $v[1];
}
}
return $filetype;
}
/**
*Get file header and file type mapping table*
*
* @return array array(array('key',value)...)
*/
public function gettypelist()
{
return array(array("ffd8ffe1","jpg") ,
array("89504e47","png"),
array("47494638","gif"),
array("49492a00","tif"),
array("424d ","bmp"),
array("41433130","dwg"),
array("38425053","ps tutorial d"),
array("7b5c727466","rtf") ,
array("3c3f786d6c","xml"),
array("68746d6c3e","html"),
array("44656c69766572792d646174","eml"),
array("cfad12fec5fd746f ","dbx"),
array("2142444e","pst"),
array("d0cf11e0","xls/doc"),
array("5374616e64617264204a","mdb") ,
array("ff575043","wpd"),
array("252150532d41646f6265","eps/ps"),
array("255044462d312e","pdf"),
array( "e3828596","pwl"),
array("504b0304","zip"),
array("52617221","rar"),
array("57415645","wav") ,
array("41564920","avi"),
array("2e7261fd","ram"),
array("2e524d46","rm"),
array("000001ba ","mpg"),
array("000001b3","mpg"),
array("6d6f6f76","mov"),
array("3026b2758e66cf11","asf"),
array("4d546864","mid"));
}
public static function getfiletype($filename)
{
if(!self::$checkclass) self::$checkclass =new self($filename);
$class=self::$checkclass;
return $class->_getfiletype($filename);
}
}