PHP根据IP地址获取所在城市具体实现

文件目录：

iplocation
-----qqwry
----------qqwry.dat
-----ipcity.class.php

ipcity.class.php文件代码：

<?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;
        }
    }

}

qqwry.dat文件下载地址：

使用演示：

include fcpath . 'plugin/iplocation/ipcity.class.php';
$city = new ipcity();
$addr = $city->getcity( '172.0.0.1' );
echo $addr; // echo 本地地址