强大的php检查文件类型
一个强大的文件类型检测函数，它可以判断你上传的文件是什么类型，利用这个函数使用文件的类型没有办法伪装过去,代码如下:
* @access public * @param string filename 文件名 * @param string limit_ext_types 允许的文件类型，用|包围的类型如：|gif|txt| * @ return string */<span id= "more-472" ></span> function check_file_type( $filename , $limit_ext_types = '' ){ $extname = strtolower ( substr ( $filename , strrpos ( $filename , '.' ) + 1)); if ( $limit_ext_types && stristr ( $limit_ext_types , '|' . $extname . '|' ) === false){ return '' ; } $str = $format = '' ; $file = @ fopen ( $filename , 'rb' ); if ( $file ){ $str = @ fread ( $file , 0x400); // 读取前 1024 个字节 @fclose( $file ); } else { $format = $extname ; } if ( $format == '' && strlen ( $str ) >= 2 ){ 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) == "xFFxD8xFF" ){ $format = 'jpg' ; } elseif ( substr ( $str ,0, 4) == 'GIF8' && $extname != 'txt' ){ $format = 'gif' ; } elseif ( substr ( $str ,0, 8) == "x89x50x4Ex47x0Dx0Ax1Ax0A" ){ $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) == "xD0xCFx11xE0" ){ // D0CF11E == DOCFILE == Microsoft Office Document if ( substr ( $str ,0x200,4) == "xECxA5xC1x00" || $extname == 'doc' ){ $format = 'doc' ; } elseif ( substr ( $str ,0x200,2) == "x09x08" || $extname == 'xls' ){ $format = 'xls' ; } elseif ( substr ( $str ,0x200,4) == "xFDxFFxFFxFF" || $extname == 'ppt' ){ $format = 'ppt' ; } } elseif ( substr ( $str ,0, 4) == "PKx03x04" ){ $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) == "x30x82x0A" ){ $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' ; } } if ( $limit_ext_types && stristr ( $limit_ext_types , '|' . $format . '|' ) === false){ $format = '' ; } return $format ; }查看更多关于强大的php检查文件类型 - php函数的详细内容...
声明：本文来自网络，不代表【好得很程序员自学网】立场，转载请注明出处：http://haodehen.cn/did30747