<?php
/**
 * 使用例子:
 * //设置参数数组
 * $config = array(
 *	'host' => 'localhost',     //数据库连接地址
 *	'port' => 3306,            //数据库连接端口
 *	'userName' => 'root',      //数据库连接账号
 *	'userPassword' => 'root',  //数据库连接密码
 *	'charset' => 'UTF8',       //数据库编码(SET NAMES)
 *	'path' => './backup/',     //备份的路径
 *	'isCompress' => 1,         //是否开启gzip压缩
 *	'isDownload' => 0,         //压缩完成后是否自动下载
 * );
 * $mr = new MySQLReback($config);
 * //设置要备份的数据库.参数可以是无限个数据库.没有参数就是全部数据库^_^
 * $mr->setDBName('artas', 'test');
 * //开始备份
 * $mr->backup();
 * //恢复数据库.参数是备份的文件名.不必带路径..因为参数已经设置路径了.
 * $mr->recover('backup@artas_test@20090707080609.sql.gz');
 */
/**
 * MySQLReback备份与恢复类
 *
 * @author Jessica
 * @link http://www.skiyo.cn
 *
 */
class MySQLReback {
	/**
	 * 数据库连接地址
	 *
	 * @var string
	 * @access private
	 */
	private $config;
	/**
	 * 数据库备份语句
	 *
	 * @var string
	 * @access private
	 */
	private $content;
	/**
	 * 欲备份的数据库名
	 *
	 * @var array
	 * @access private
	 */
	private $dbName = array();
	/**
	 * 操作系统的目录分隔符
	 */
	const DIR_SEP = DIRECTORY_SEPARATOR;
	/**
	 * 构造器
	 *
	 * @param string $host          数据库连接地址
	 * @param int $port             数据库连接端口
	 * @param string $userName      数据库连接账户
	 * @param string $userPassword  数据库连接密码
	 * @access public
	 */
	public function __construct($config) {
		$this->config = $config;
		header ( "Content-type: text/html;charset=utf-8" );
		$this->connect();
	}
	/**
	 * 连接数据库
	 *
	 * @access private
	 * @return void
	 */
	private function connect() {
		if (mysql_connect($this->config['host']. ':' . $this->config['port'], $this->config['userName'], $this->config['userPassword'])) {
			mysql_query("SET NAMES '{$this->config['charset']}'");
			mysql_query("set interactive_timeout=24*3600");
		} else {
			$this->throwException('无法连接到数据库!');
		}
	}
	/**
	 * 设置欲备份的数据库
	 *
	 * @param string $dbName 数据库名(支持多个参数.默认为全部的数据库)
	 * @access public
	 * @return void
	 */
	public function setDBName($dbName = '*') {
		if ($dbName == '*') {
			$rs = mysql_list_dbs();
			$rows = mysql_num_rows($rs);
			if($rows){
				for($i=0;$i<$rows;$i++){
					$dbName = mysql_tablename($rs,$i);
					//这些数据库不需要备份
					$block = array('information_schema', 'mysql');
					if (!in_array($dbName, $block)) {
						$this->dbName[] = $dbName;
					}
				}
			} else {
				$this->throwException('没有任何数据库!');
			}
		} else {
			$this->dbName = func_get_args();
		}
	}
	/**
	 * 获取备份文件
	 *
	 * @param string $fileName 文件名
	 * @access private
	 * @return void
	 */
	private function getFile($fileName) {
		$this->content = '';
		$fileName = $this->trimPath($this->config['path'] . self::DIR_SEP .$fileName);
		if (is_file($fileName)) {
			$ext = strrchr($fileName, '.');
			if ($ext == '.sql') {
				$this->content = file_get_contents($fileName);
			} elseif ($ext == '.gz') {
				$this->content = implode('', gzfile($fileName));
			} else {
				$this->throwException('无法识别的文件格式!');
			}
		} else {
			$this->throwException('文件不存在!');
		}
	}
	/**
	 * 备份文件
	 *
	 * @access private
	 */
	private function setFile() {
		$recognize = '';
		$recognize = implode('_', $this->dbName);
		$fileName = $this->trimPath($this->config['path'] . self::DIR_SEP . 'backup@'.$recognize."@".date('YmdHis').'.sql');
		$path = $this->setPath($fileName);
		if ($path !== true) {
			$this->throwException("无法创建备份目录目录 '$path'");
		}

		if ($this->config['isCompress'] == 0) {
			if (!file_put_contents($fileName, $this->content, LOCK_EX)) {
				$this->throwException('写入文件失败,请检查磁盘空间或者权限!');
			}
		} else {
			if (function_exists('gzwrite')) {
				$fileName .= '.gz';
				if ($gz = gzopen($fileName, 'wb')) {
					gzwrite($gz, $this->content);
					gzclose($gz);
				} else {
					$this->throwException('写入文件失败,请检查磁盘空间或者权限!');
				}
			} else {
				$this->throwException('没有开启gzip扩展!');
			}
		}
		if ($this->config['isDownload']) {
			$this->downloadFile($fileName);
		}
	}

	/**
     * 将路径修正为适合操作系统的形式
     *
     * @param  string $path 路径名称
     * @return string
     */
	private function trimPath($path) {
		return str_replace(array('/', '\\', '//', '\\\\'), self::DIR_SEP, $path);
	}
	/**
	 * 设置并创建目录
	 *
	 * @param $fileName 路径
	 * @return mixed
	 * @access private
	 */
	private function setPath($fileName)	{
		$dirs = explode(self::DIR_SEP, dirname($fileName));
		$tmp = '';
		foreach ($dirs as $dir) {
			$tmp .= $dir . self::DIR_SEP;
			if (!file_exists($tmp) && !@mkdir($tmp, 0777))
			return $tmp;
		}
		return true;
	}
	/**
	 * 下载文件
	 *
	 * @param string $fileName 路径
	 */
	private function downloadFile($fileName) {
		header ("Cache-Control: must-revalidate, post-check=0, pre-check=0");
		header('Content-Description: File Transfer');
		header('Content-Type: application/octet-stream');
		header('Content-Length: ' . filesize($fileName));
		header('Content-Disposition: attachment; filename=' . basename($fileName));
		readfile($fileName);
	}

	/**
	 * 给表名或者数据库名加上``
	 *
	 * @param string $str
	 * @return string
	 * @access private
	 */
	private function backquote($str) {
		return "`{$str}`";
	}

	/**
	 * 获取数据库的所有表
	 *
	 * @param string $dbName 数据库名
	 * @return array
	 * @access private
	 */
	private function getTables($dbName){
		$rs = mysql_list_tables($dbName);
		$rows = mysql_num_rows($rs);
		for ($i=0; $i<$rows; $i++) {
			$tables[] = mysql_tablename($rs, $i);
		}
		return $tables;
	}

	/**
	 * 将数组按照字节数分割成小数组
	 *
	 * @param array $array  数组
	 * @param int $byte     字节数
	 * @return array
	 */
	private function chunkArrayByByte($array, $byte = 5120) {
		$i=0;
		$sum=0;
		foreach ($array as $v) {
			$sum += strlen($v);
			if ($sum < $byte) {
				$return[$i][] = $v;
			} elseif ($sum == $byte) {
				$return[++$i][] = $v;
				$sum = 0;
			} else {
				$return[++$i][] = $v;
				$i++;
				$sum = 0;
			}
		}
		return $return;
	}

	/**
	 * 备份
	 *
	 * @access public
	 */
	public function backup() {
		$this->content = '/* This file is created by MySQLReback ' . date('Y-m-d H:i:s') . ' */';
		//循环数据库
		foreach ($this->dbName as $dbName) {
			$qDbName = $this->backquote($dbName);
			$rs = mysql_query("SHOW CREATE DATABASE {$qDbName}");
			if ($row = mysql_fetch_row($rs)) {
				//建立数据库
				$this->content .= "\r\n /* 创建数据库 {$qDbName} */";
				//必须设置一个分割符..单用分号是不够安全的.
				$this->content .= "\r\n DROP DATABASE IF EXISTS {$qDbName};/* MySQLReback Separation */ {$row[1]};/* MySQLReback Separation */";
				mysql_select_db($dbName);
				//取得表
				$tables = $this->getTables($dbName);
				foreach ($tables as $table) {
					$table = $this->backquote($table);
					$tableRs = mysql_query("SHOW CREATE TABLE {$table}");
					if ($tableRow = mysql_fetch_row($tableRs)) {
						//建表
						$this->content .= "\r\n /* 创建表结构 {$table}  */";
						$this->content .= "\r\n DROP TABLE IF EXISTS {$table};/* MySQLReback Separation */ {$tableRow[1]};/* MySQLReback Separation */";
						//获取数据
						$tableDateRs = mysql_query("SELECT * FROM {$table}");
						$valuesArr = array();
						$values = '';
						while ($tableDateRow = mysql_fetch_row($tableDateRs)) {
							//组合INSERT的VALUE
							foreach ($tableDateRow as &$v) {
								$v = "'" . addslashes($v) . "'"; //别忘了转义.
							}
							$valuesArr[] = '(' . implode(',', $tableDateRow) . ')';
						}
						$temp = $this->chunkArrayByByte($valuesArr);
						if (is_array($temp)) {
							foreach ($temp as $v) {
								$values = implode(',', $v) . ';/* MySQLReback Separation */';
								//空的数据表就不组合SQL语句了..因为没得组合
								if ($values != ';/* MySQLReback Separation */') {
									$this->content .= "\r\n /* 插入数据 {$table} */";
									$this->content .= "\r\n INSERT INTO {$table} VALUES {$values}";
								}
							}
						}
					}
				}
			} else {
				$this->throwException('未能找到数据库!');
			}
		}
		if (!empty($this->content)) {
			$this->setFile();
		}
		//大事搞成
		return true;
	}
	/**
	 * 恢复数据库
	 *
	 * @param string $fileName 文件名
	 * @access public
	 */
	public function recover($fileName) {
		$this->getFile($fileName);
		if (!empty($this->content)) {
			$content = explode(';/* MySQLReback Separation */', $this->content);
			foreach ($content as $sql) {
				$sql = trim($sql);
				//空的SQL会被认为是错误的
				if (!empty($sql)) {
					$rs = mysql_query($sql);
					if ($rs) {
						//一定要选择数据库.不然多库恢复会出错
						if (strstr($sql, 'CREATE DATABASE')) {
							$dbNameArr = sscanf($sql, 'CREATE DATABASE %s');
							$dbName = trim($dbNameArr[0], '`');
							mysql_select_db($dbName);
						}
					} else {
						$this->throwException('备份文件被损坏!' . mysql_error());
					}
				}
			}
		} else {
			$this->throwException('无法读取备份文件!');
		}
		//大事搞成
		return true;
	}
	/**
	 * 抛出一个异常信息
	 *
	 * @param string $error
	 * @access private
	 * @return void
	 */
	private function throwException($error) {
		throw new Exception($error);
	}
}