Sometimes we don't do it well. Some people may have saved some files, but he has changed the extension so that it is within our file type. Cannot be displayed when a single actual visit (because the extension does not match the contents of the file). The following PHP class may be helpful to us.
first, the PHP detection class
First of all, the above file header and file type mapping relationship from the Internet, if you have a new file to check, only need to add the mapping. If you need to know the file header information, you can open the standard file lookup by using the tool: Winhex. Such as:
Code:
Copy CodeThe code is as follows:
/* Get the file type by filename *
* @author chengmo*
* @copyright Cnblog.com/chengmo 2010-10-17
* @version 0.1
* $filename = "d:/1.png"; Echo Cfiletypecheck::getfiletype ($filename); Printing: PNG
*/
Class Cfiletypecheck
{
private static $_typelist=array ();
private static $CheckClass =null;
Private function __construct ($filename)
{
self::$_typelist= $this->gettypelist ();
}
/**
* Process file Type mapping Relationship table *
*
* @param string $filename file type
* @return string file type, not found returned: other
*/
Private Function _getfiletype ($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); Read-only 15 bytes each different file type, header information is not the same.
Fclose ($file);
$typelist =self::$_typelist;
foreach ($typelist as $v)
{
$blen =strlen (Pack ("h*", $v [0]); Gets the number of file header tokens in bytes
$tbin =substr ($bin, 0,intval ($blen)); Need to compare file header lengths
if (Strtolower ($v [0]) ==strtolower (Array_shift (Unpack ("h*", $tbin))))
{
return $v [1];
}
}
return $filetype;
}
/**
* Get file header and File type mapping table *
*
* @return Array Array (' key ', value) ...)
*/
Public Function Gettypelist ()
{
return Array (Array ("Ffd8ffe1", "jpg"),
Array ("89504E47", "PNG"),
Array ("47494638", "gif"),
Array ("49492a00", "TIF"),
Array ("424D", "BMP"),
Array ("41433130", "DWG"),
Array ("38425053", "PSD"),
Array ("7b5c727466", "RTF"),
Array ("3C3F786D6C", "xml"),
Array ("68746d6c3e", "html"),
Array ("44656c69766572792d646174", "eml"),
Array ("cfad12fec5fd746f", "dbx"),
Array ("2142444E", "PST"),
Array ("D0cf11e0", "Xls/doc"),
Array ("5374616e64617264204a", "MDB"),
Array ("FF575043", "WPD"),
Array ("252150532d41646f6265", "Eps/ps"),
Array ("255044462d312e", "PDF"),
Array ("E3828596", "PWL"),
Array ("504b0304", "zip"),
Array ("52617221", "rar"),
Array ("57415645", "wav"),
Array ("41564920", "avi"),
Array ("2E7261FD", "Ram"),
Array ("2e524d46", "rm"),
Array ("000001BA", "mpg"),
Array ("000001b3", "mpg"),
Array ("6d6f6f76", "mov"),
Array ("3026b2758e66cf11", "ASF"),
Array ("4d546864", "mid"));
}
public static function Getfiletype ($filename)
{
if (!self:: $CheckClass) Self:: $CheckClass =new self ($filename);
$class =self:: $CheckClass;
Return $class->_getfiletype ($filename);
}
}
How to get the first byte code:
Can see: PNG file, the header is 4 bytes (the header tag is how many bytes need to check the relevant data to determine), corresponds to: 89504E47
If you are not familiar with PHP's pack unpack, you can view:
PHP Park, Unpark, Ord function usage (binary stream interface application example)
Invoke instance:
Copy CodeThe code is as follows:
$filename = "D:/1.png";
echo $filename, "\ T", Cfiletypecheck::getfiletype ($filename), "\ r \ n";
$filename = "D:/test.doc";
echo $filename, "\ T", Cfiletypecheck::getfiletype ($filename), "\ r \ n";
D:/1.png png
D:/test.doc Xls/doc
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