php实现从mysql备份sql文件中提取特定数据

来源：互联网发布：php 反射函数参数类型编辑：程序博客网时间：2024/05/21 10:06

案例场景：玩家数据打包为一个blob存在mysql中，需要查看玩家特定时间的数据

策略：从dump sql文件中提取玩家数据块

实现：为了简单和跨平台，用php编写

具体步骤如图，1为简单版，2为优化版。

备注：关键点在于步长一定要大于玩家数据大小，这样如果搜索到起始位置，至多再有一次read就可以得到玩家数据.

另外重要的一点是：sql文件是mysqldump的输出文件，blob都是转义过的，不能拿来直接当作二进制数据做内存解析，只能再mysql导入到db中才能使用

源代码：

<?phpfunction write_data($uid, $data){        $fp = fopen("$uid"."_dump.rar", 'wb');$real_data = "replace into kakag.t_player_data_1_1 values($uid,'".$data."');";        fwrite($fp, $real_data);        fclose($fp);//echo md5($real_data)."\n";}function get_real_data($uid, $data, &$has_start_flag){$start_flag = "($uid,'";$start_pos = strpos($data, $start_flag);if($start_pos != false){$has_start_flag = true;//first state$check_flag = "'),(";$end_pos = strpos($data, $check_flag, $start_pos);if($end_pos != false){$new_start_pos = $start_pos + strlen($start_flag);$real_data = substr($data, $new_start_pos, $end_pos - $new_start_pos );write_data($uid, $real_data);return true;}//second state$check_flag = "');";$end_pos = strpos($data, $check_flag, $start_pos);if($end_pos != false){$new_start_pos = $start_pos + strlen($start_flag);$real_data = substr($data, $new_start_pos, $end_pos - $new_start_pos );write_data($uid, $real_data);return true;}}else{return false;}}function read_data($uid, $file_name){$fp = fopen($file_name, 'r');$once_size = 1024 * 500;while(1){$data = fread($fp, $once_size);if($data != ""){$has_start_flag = false;$ret = get_real_data($uid, $data, $has_start_flag);if($ret == true){echo "load user data success\n";break;}else{if($has_start_flag == true){$data_extra = fread($fp, $once_size);if($data_extra != ""){$new_data = $data.$data_extra;$has_start_flag = false;$ret = get_real_data($uid, $new_data, $has_start_flag);if($ret == true){echo "load user data success\n";break;}else{break;}}else{break;}}else{continue;}}}else{break;}}fclose($fp);}read_data($argv[1], $argv[2]);?>

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