PHP：根据IP地址获取所在城市

<?php    class ipCity {        /**      * 根据ip地址获取对应所在城市      * @param type $userip 用户IP地址      * @return string      */      public function getCity( $userip, $dat_path = '' ) {          //IP数据库路径，这里用的是QQ IP数据库 20110405 纯真版          empty( $dat_path ) && $dat_path = FCPATH . 'plugin/ipLocation/qqwry/QQWry.Dat';          //判断IP地址是否有效          if ( preg_match( "/^([0-9]{1,3}.){3}[0-9]{1,3}$/", $userip ) == 0 ) {              return 'IP Address Invalid';          }          //打开IP数据库          if ( !$fd = @fopen( $dat_path, 'rb' ) ) {              return 'IP data file not exists or access denied';          }          //explode函数分解IP地址，运算得出整数形结果          $userip = explode( '.', $userip );          $useripNum = $userip[0] * 16777216 + $userip[1] * 65536 + $userip[2] * 256 + $userip[3];          //获取IP地址索引开始和结束位置          $DataBegin = fread( $fd, 4 );          $DataEnd = fread( $fd, 4 );          $useripbegin = implode( '', unpack( 'L', $DataBegin ) );          if ( $useripbegin < 0 )              $useripbegin += pow( 2, 32 );          $useripend = implode( '', unpack( 'L', $DataEnd ) );          if ( $useripend < 0 )              $useripend += pow( 2, 32 );          $useripAllNum = ($useripend - $useripbegin) / 7 + 1;          $BeginNum = 0;          $EndNum = $useripAllNum;          //使用二分查找法从索引记录中搜索匹配的IP地址记录          while ( $userip1num > $useripNum || $userip2num < $useripNum ) {              $Middle = intval( ($EndNum + $BeginNum) / 2 );              //偏移指针到索引位置读取4个字节              fseek( $fd, $useripbegin + 7 * $Middle );              $useripData1 = fread( $fd, 4 );              if ( strlen( $useripData1 ) < 4 ) {                  fclose( $fd );                  return 'File Error';              }              //提取出来的数据转换成长整形，如果数据是负数则加上2的32次幂              $userip1num = implode( '', unpack( 'L', $useripData1 ) );              if ( $userip1num < 0 )                  $userip1num += pow( 2, 32 );              //提取的长整型数大于我们IP地址则修改结束位置进行下一次循环              if ( $userip1num > $useripNum ) {                  $EndNum = $Middle;                  continue;              }              //取完上一个索引后取下一个索引              $DataSeek = fread( $fd, 3 );              if ( strlen( $DataSeek ) < 3 ) {                  fclose( $fd );                  return 'File Error';              }              $DataSeek = implode( '', unpack( 'L', $DataSeek . chr( 0 ) ) );              fseek( $fd, $DataSeek );              $useripData2 = fread( $fd, 4 );              if ( strlen( $useripData2 ) < 4 ) {                  fclose( $fd );                  return 'File Error';              }              $userip2num = implode( '', unpack( 'L', $useripData2 ) );              if ( $userip2num < 0 )                  $userip2num += pow( 2, 32 );              //找不到IP地址对应城市              if ( $userip2num < $useripNum ) {                  if ( $Middle == $BeginNum ) {                      fclose( $fd );                      return 'No Data';                  }                  $BeginNum = $Middle;              }          }          $useripFlag = fread( $fd, 1 );          if ( $useripFlag == chr( 1 ) ) {              $useripSeek = fread( $fd, 3 );              if ( strlen( $useripSeek ) < 3 ) {                  fclose( $fd );                  return 'System Error';              }              $useripSeek = implode( '', unpack( 'L', $useripSeek . chr( 0 ) ) );              fseek( $fd, $useripSeek );              $useripFlag = fread( $fd, 1 );          }          if ( $useripFlag == chr( 2 ) ) {              $AddrSeek = fread( $fd, 3 );              if ( strlen( $AddrSeek ) < 3 ) {                  fclose( $fd );                  return 'System Error';              }              $useripFlag = fread( $fd, 1 );              if ( $useripFlag == chr( 2 ) ) {                  $AddrSeek2 = fread( $fd, 3 );                  if ( strlen( $AddrSeek2 ) < 3 ) {                      fclose( $fd );                      return 'System Error';                  }                  $AddrSeek2 = implode( '', unpack( 'L', $AddrSeek2 . chr( 0 ) ) );                  fseek( $fd, $AddrSeek2 );              } else {                  fseek( $fd, -1, SEEK_CUR );              }              while ( ($char = fread( $fd, 1 )) != chr( 0 ) )                  $useripAddr2 .= $char;              $AddrSeek = implode( '', unpack( 'L', $AddrSeek . chr( 0 ) ) );              fseek( $fd, $AddrSeek );              while ( ($char = fread( $fd, 1 )) != chr( 0 ) )                  $useripAddr1 .= $char;          } else {              fseek( $fd, -1, SEEK_CUR );              while ( ($char = fread( $fd, 1 )) != chr( 0 ) )                  $useripAddr1 .= $char;              $useripFlag = fread( $fd, 1 );              if ( $useripFlag == chr( 2 ) ) {                  $AddrSeek2 = fread( $fd, 3 );                  if ( strlen( $AddrSeek2 ) < 3 ) {                      fclose( $fd );                      return 'System Error';                  }                  $AddrSeek2 = implode( '', unpack( 'L', $AddrSeek2 . chr( 0 ) ) );                  fseek( $fd, $AddrSeek2 );              } else {                  fseek( $fd, -1, SEEK_CUR );              }              while ( ($char = fread( $fd, 1 )) != chr( 0 ) ) {                  $useripAddr2 .= $char;              }          }          fclose( $fd );          //返回IP地址对应的城市结果          if ( preg_match( '/http/i', $useripAddr2 ) ) {              $useripAddr2 = '';          }          $useripaddr = "$useripAddr1 $useripAddr2";          $useripaddr = preg_replace( '/CZ88.Net/is', '', $useripaddr );          $useripaddr = preg_replace( '/^s*/is', '', $useripaddr );          $useripaddr = preg_replace( '/s*$/is', '', $useripaddr );          if ( preg_match( '/http/i', $useripaddr ) || $useripaddr == '' ) {              $useripaddr = 'No Data';          } elseif ( !$this->is_utf8( $useripaddr ) ) {              $useripaddr = iconv( 'GBK', 'UTF-8', $useripaddr );          }          return $useripaddr;      }        /**      * 判断是否我utf-8编码的字符串      * @param type $string      * @return boolean      */      private function is_utf8( $string ) {          if ( preg_match( "/^([" . chr( 228 ) . "-" . chr( 233 ) . "]{1}[" . chr( 128 ) . "-" . chr( 191 ) . "]{1}[" . chr( 128 ) . "-" . chr( 191 ) . "]{1}){1}/", $string ) == true || preg_match( "/([" . chr( 228 ) . "-" . chr( 233 ) . "]{1}[" . chr( 128 ) . "-" . chr( 191 ) . "]{1}[" . chr( 128 ) . "-" . chr( 191 ) . "]{1}){1}$/", $string ) == true || preg_match( "/([" . chr( 228 ) . "-" . chr( 233 ) . "]{1}[" . chr( 128 ) . "-" . chr( 191 ) . "]{1}[" . chr( 128 ) . "-" . chr( 191 ) . "]{1}){2,}/", $string ) == true ) {              return true;          } else {              return false;          }      }    }  

include FCPATH . 'plugin/ipLocation/ipCity.class.php';  $city = new ipCity();  $addr = $city->getCity( '172.0.0.1' );  echo $addr; // echo 本地地址