PHP如何根据文件头检测文件类型实例代码分享！

前言

什么是文件头部Bom？ 说白了，就是在保存文件的时候，文件前面会多出一串隐藏的字符，文件签名一般都在文件的头部，如果你用十六进制方式查看文件，你就可以看到文件的一些签名信息。如用uestudio以十六进制方式查看zip格式的文件，其文件内容头部有50 4B 03 04这样的十六进制信息。同理jpg文件状况有FF D8 FF E0 xx xx 4A 46这样的十六进制信息，其实这此十六进制都是表示一些特殊字条。

php怎么样验证文件类型？

先来看一个简单的方法：

  <?php  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);

下来提供一个类的实现：

  <?php  /*通过文件名，获得文件类型*   *@author chengmo QQ:8292669*   *@copyright <a href="https://www.cnblogs.com/chengmo">https://www.cnblogs.com/chengmo</a> 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";

或者可以这么检测：

  <?php  $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;

总结

• 1
• 2
• 下一页