PHP detects file type based on file header_PHP tutorial

File signatures are generally at the header of the file. If you view the file in hexadecimal mode, you can see some signature information of the file. For example, if you use uestudio to view a file in zip format in hexadecimal format, the file content header will contain hexadecimal information such as 50 4B 03 04. Similarly, the jpg file status has hexadecimal information such as FF D8 FF E0 xx xx 4A 46. In fact, these hexadecimal numbers represent some special notes.

How to verify file type in php? Let’s look at a simple method first:

	function checkFileType($fileName){  
        $file = fopen($fileName, "rb");  
        $bin = fread($file, 2); //只读2字节  
        fclose($file);  
		// C为无符号整数，网上搜到的都是c，为有符号整数，这样会产生负数判断不正常 
        $strInfo  = @unpack("C2chars", $bin); 
        $typeCode = intval($strInfo['chars1'].$strInfo['chars2']);  
        $fileType = '';  

		switch( $typeCode )
		{
			case '255216':
				return $typeCode. ' : ' .'jpg';
				break;
			case '7173':
				return $typeCode. ' : ' .'gif';
				break;
			case '13780':
				return $typeCode. ' : ' .'png';
				break;
			case '6677':
				return $typeCode. ' : ' .'bmp';
				break;
			case '7790':
				return $typeCode. ' : ' .'exe';
				break;
			case '7784':
				return $typeCode. ' : ' .'midi';
				break;
			case '8297':
				return $typeCode. ' : ' .'rar';
				break;
			default:
				return $typeCode. ' : ' .'Unknown';
				break;
		}
		//return $typeCode;
    }
	
	$file_name = '11.doc';
	echo checkFileType($file_name);

Come down and provide the implementation of a class:

/*通过文件名，获得文件类型*
 *@author chengmo QQ:8292669*
 *@copyright http://www.cnblogs.com/chengmo 2010-10-17
 *@version 0.1
 *$filename="d:/1.png";echo cFileTypeCheck::getFileType($filename); 打印：png
 */
class cFileTypeCheck
{
    private static $_TypeList=array();
    private static $CheckClass=null;
    private function __construct($filename)
    {
        self::$_TypeList=$this->getTypeList();
    }
 
    /**
     *处理文件类型映射关系表*
     *
     * @param string $filename 文件类型
     * @return string 文件类型，没有找到返回：other
     */
    private function _getFileType($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); //只读15字节 各个不同文件类型，头信息不一样。
        fclose($file);
         
        $typelist=self::$_TypeList;
        foreach ($typelist as $v)
        {
            $blen=strlen(pack("H*",$v[0])); //得到文件头标记字节数
            $tbin=substr($bin,0,intval($blen)); ///需要比较文件头长度
             
            if(strtolower($v[0])==strtolower(array_shift(unpack("H*",$tbin)))) 
            {
                return $v[1];
            }
        }
        return $filetype;
    }
     
    /**
     *得到文件头与文件类型映射表*
     *
     * @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","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);
    }
	
}

$filename="22.jpg";
echo $filename,"t",cFileTypeCheck::getFileType($filename),"rn";
$filename="11.doc";
echo $filename,"t",cFileTypeCheck::getFileType($filename),"rn";

Or you can check it like this:

$filename = '22.jpg';
 
$extname = strtolower(substr($filename, strrpos($filename, '.') + 1));
echo $extname.'<br />';
$file = @fopen($filename, 'rb');
    if ($file)
    {
        $str = @fread($file, 0x400); // 读取前 1024 个字节
		echo substr($str, 0, 4);
        @fclose($file);
    }
 	if (substr($str, 0, 4) == 'MThd' && $extname != 'txt')
        {
            $format = 'mid';
        }
        elseif (substr($str, 0, 4) == 'RIFF' && $extname == 'wav')
        {
            $format = 'wav';
        }
        elseif (substr($str ,0, 3) == "/xFF/xD8/xFF")
        {
            $format = 'jpg';
        }
        elseif (substr($str ,0, 4) == 'GIF8' && $extname != 'txt')
        {
            $format = 'gif';
        }
        elseif (substr($str ,0, 8 ) == "/x89/x50/x4E/x47/x0D/x0A/x1A/x0A")
        {
            $format = 'png';
        }
        elseif (substr($str ,0, 2) == 'BM' && $extname != 'txt')
        {
            $format = 'bmp';
        }
        elseif ((substr($str ,0, 3) == 'CWS' || substr($str ,0, 3) == 'FWS') && $extname != 'txt')
        {
            $format = 'swf';
        }
        elseif (substr($str ,0, 4) == "/xD0/xCF/x11/xE0")
        {   // D0CF11E == DOCFILE == Microsoft Office Document
            if (substr($str,0x200,4) == "/xEC/xA5/xC1/x00" || $extname == 'doc')
            {
                $format = 'doc';
            }
            elseif (substr($str,0x200,2) == "/x09/x08" || $extname == 'xls')
            {
                $format = 'xls';
            } elseif (substr($str,0x200,4) == "/xFD/xFF/xFF/xFF" || $extname == 'ppt')
            {
                $format = 'ppt';
            }
        } elseif (substr($str ,0, 4) == "PK/x03/x04")
        {
            $format = 'zip';
        } elseif (substr($str ,0, 4) == 'Rar!' && $extname != 'txt')
        {
            $format = 'rar';
        } elseif (substr($str ,0, 4) == "/x25PDF")
        {
            $format = 'pdf';
        } elseif (substr($str ,0, 3) == "/x30/x82/x0A")
        {
            $format = 'cert';
        } elseif (substr($str ,0, 4) == 'ITSF' && $extname != 'txt')
        {
            $format = 'chm';
        } elseif (substr($str ,0, 4) == "/x2ERMF")
        {
            $format = 'rm';
        } elseif ($extname == 'sql')
        {
            $format = 'sql';
        } elseif ($extname == 'txt')
        {
            $format = 'txt';
        }
		
		echo $format;

http://www.bkjia.com/PHPjc/752375.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/752375.htmlTechArticleFile signatures are generally at the head of the file. If you view the file in hexadecimal mode, you can See some signature information of the file. If you use uestudio to view the zip format in hexadecimal format...