baoyu777永久免费视频,一区二区三区成人,亚洲天堂2021av无码

主頁 > 知識庫 > PHP如何根據(jù)文件頭檢測文件類型實例代碼

PHP如何根據(jù)文件頭檢測文件類型實例代碼

前言

什么是文件頭部Bom？說白了，就是在保存文件的時候，文件前面會多出一串隱藏的字符，文件簽名一般都在文件的頭部，如果你用十六進制方式查看文件，你就可以看到文件的一些簽名信息。如用uestudio以十六進制方式查看zip格式的文件，其文件內容頭部有50 4B 03 04這樣的十六進制信息。同理jpg文件狀況有FF D8 FF E0 xx xx 4A 46這樣的十六進制信息，其實這此十六進制都是表示一些特殊字條。

php怎么樣驗證文件類型？

先來看一個簡單的方法：

?php
function checkFileType($fileName){ 
  $file = fopen($fileName, "rb"); 
  $bin = fread($file, 2); //只讀2字節(jié) 
  fclose($file); 
 // C為無符號整數(shù)，網上搜到的都是c，為有符號整數(shù)，這樣會產生負數(shù)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(xiàn)：

?php
/*通過文件名，獲得文件類型*
 *@author chengmo QQ:8292669*
 *@copyright a >http://www.cnblogs.com/chengmo/a> 2010-10-17
 *@version 0.1
 *$filename="d:/1.png";echo cFileTypeCheck::getFileType($filename); 打?。簆ng
 */
class cFileTypeCheck
{
  private static $_TypeList=array();
  private static $CheckClass=null;
  private function __construct($filename)
  {
    self::$_TypeList=$this->getTypeList();
  }

  /**
   *處理文件類型映射關系表*
   *
   * @param string $filename 文件類型
   * @return string 文件類型，沒有找到返回：other
   */
  private function _getFileType($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); //只讀15字節(jié) 各個不同文件類型，頭信息不一樣。
    fclose($file);

    $typelist=self::$_TypeList;
    foreach ($typelist as $v)
    {
      $blen=strlen(pack("H*",$v[0])); //得到文件頭標記字節(jié)數(shù)
      $tbin=substr($bin,0,intval($blen)); ///需要比較文件頭長度

      if(strtolower($v[0])==strtolower(array_shift(unpack("H*",$tbin))))
      {
        return $v[1];
      }
    }
    return $filetype;
  }

  /**
   *得到文件頭與文件類型映射表*
   *
   * @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";

或者可以這么檢測：

?php
$filename = '22.jpg';

$extname = strtolower(substr($filename, strrpos($filename, '.') + 1));
echo $extname.'br />';
$file = @fopen($filename, 'rb');
  if ($file)
  {
    $str = @fread($file, 0x400); // 讀取前 1024 個字節(jié)
 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;

總結

以上就是這篇文章的全部內容了，希望本文的內容對大家的學習或者工作具有一定的參考學習價值，如果有疑問大家可以留言交流，謝謝大家對腳本之家的支持。

您可能感興趣的文章: