PHP根據檔案頭檢測檔案類型_PHP教程

檔案簽名一般都在檔案的頭部，如果你用十六進位方式查看檔案，你就可以看到檔案的一些簽名資訊。如用uestudio以十六進位方式查看zip格式的檔案，其檔案內容標題部有50 4B 03 04這樣的十六進位資訊。同理jpg檔案狀況有FF D8 FF E0 xx xx 4A 46這樣的十六進位資訊，其實這此十六進位都是表示一些特殊字條。

php怎麼樣驗證檔案類型？先來看一個簡單的方法：

function checkFileType($fileName){          $file = fopen($fileName, "rb");          $bin = fread($file, 2); //唯讀2位元組          fclose($file);  // C為不帶正負號的整數，網上搜到的都是c，為有符號整數，這樣會產生負數判斷不正常         $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);

下來提供一個類的實現：

/*通過檔案名稱，獲得檔案類型* *@author chengmo QQ:8292669* *@copyright http://www.cnblogs.com/chengmo 2010-10-17 *@version 0.1 *$filename="d:/1.png";echo cFileTypeCheck::getFileType($filename); 列印：png */class cFileTypeCheck{    private static $_TypeList=array();    private static $CheckClass=null;    private function __construct($filename)    {        self::$_TypeList=$this->getTypeList();    }     /**     *處理檔案類型映射關係表*     *     * @param string $filename 檔案類型     * @return string 檔案類型，沒有找到返回：other     */    private function _getFileType($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); //唯讀15位元組 各個不同檔案類型，頭資訊不一樣。        fclose($file);                 $typelist=self::$_TypeList;        foreach ($typelist as $v)        {            $blen=strlen(pack("H*",$v[0])); //得到檔案頭標記位元組數            $tbin=substr($bin,0,intval($blen)); ///需要比較檔案頭長度                         if(strtolower($v[0])==strtolower(array_shift(unpack("H*",$tbin))))             {                return $v[1];            }        }        return $filetype;    }         /**     *得到檔案頭與檔案類型映射表*     *     * @return array array(array('key',value)...)     */    public function getTypeList()    {        return array(array("FFD8FFE1","jpg"),        array("89504E47","png"),        array("47494638","gif"),        array("49492A00","tif"),        array("424D","bmp"),        array("41433130","dwg"),        array("38425053","psd"),        array("7B5C727466","rtf"),        array("3C3F786D6C","xml"),        array("68746D6C3E","html"),        array("44656C69766572792D646174","eml"),        array("CFAD12FEC5FD746F","dbx"),        array("2142444E","pst"),        array("D0CF11E0","xls/doc"),        array("5374616E64617264204A","mdb"),        array("FF575043","wpd"),        array("252150532D41646F6265","eps/ps"),        array("255044462D312E","pdf"),        array("E3828596","pwl"),        array("504B0304","zip"),        array("52617221","rar"),        array("57415645","wav"),        array("41564920","avi"),        array("2E7261FD","ram"),        array("2E524D46","rm"),        array("000001BA","mpg"),        array("000001B3","mpg"),        array("6D6F6F76","mov"),        array("3026B2758E66CF11","asf"),        array("4D546864","mid"));    }      public static function getFileType($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";

或者可以這麼檢測：

$filename = '22.jpg'; $extname = strtolower(substr($filename, strrpos($filename, '.') + 1));echo $extname.'
';$file = @fopen($filename, 'rb');    if ($file)    {        $str = @fread($file, 0x400); // 讀取前 1024 個位元組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.htmlTechArticle檔案簽名一般都在檔案的頭部，如果你用十六進位方式查看檔案，你就可以看到檔案的一些簽名資訊。如用uestudio以十六進位方式查看zip格...

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