php 實現Mysql讀寫分離操作及數據庫連接類

之前發佈了

MySQL主從複製（Master-Slave）與讀寫分離（MySQL-Proxy）實踐 

今天來發佈一個，php的連接類.....

連接案例：

<?php

require_once('mysql_rw_php.class.php');

$db_rw = array(
	'dbhost'=>'www.aslibra.com',
	'dbuser'=>'aslibra',
	'dbpw'=>'www.aslibra.com',
	'dbname'=>'test'
);

$db_ro = array(
	array(
		'dbhost'=>'www.aslibra.com:4306',
		'dbuser'=>'aslibra',
		'dbpw'=>'www.aslibra.com'
	)
);

$DB = new mysql_rw_php;

//寫入連接，單服務器操作
$DB->connect($db_rw[dbhost], $db_rw[dbuser], $db_rw[dbpw], $db_rw[dbname]);  

//讀取連接，可以多服務器操作
$DB->connect_ro($db_ro[0][dbhost], $db_ro[0][dbuser], $db_ro[0][dbpw]);
$DB->set_ro_list($db_ro);


//send to rw
$sql = "insert into a set a='test'";
$DB->query($sql);

//send to ro
$sql = "select * from a";
$qr = $DB->query($sql);
while($row = $DB->fetch_array($qr)){
	echo $row[a];
}
?>

連接類：

<?php

class mysql_rw_php {

	//查詢個數
	var $querynum = 0;
	//當前操作的數據庫連接
	var $link = null;
	//字符集
	var $charset;
	//當前數據庫
	var $cur_db = '';

	//是否存在有效的只讀數據庫連接
	var $ro_exist = false;
	//只讀數據庫連接
	var $link_ro = null;
	//讀寫數據庫連接
	var $link_rw = null;

	function mysql_rw_php(){
	}

	function connect($dbhost, $dbuser, $dbpw, $dbname = '', $pconnect = 0, $halt = TRUE) {
		if($pconnect) {
			if(!$this->link = @mysql_pconnect($dbhost, $dbuser, $dbpw)) {
				$halt && $this->halt('Can not connect to MySQL server');
			}
		} else {
			if(!$this->link = @mysql_connect($dbhost, $dbuser, $dbpw)) {
				$halt && $this->halt('Can not connect to MySQL server');
			}
		}
		
		//只讀連接失敗
		if(!$this->link && !$halt) return false;
		
		//未初始化rw時，第一個連接作爲rw
		if($this->link_rw == null)
			$this->link_rw = $this->link;

		if($this->version() > '4.1') {
			if($this->charset) {
				@mysql_query("SET character_set_connection=$this->charset, character_set_results=$this->charset, character_set_client=binary", $this->link);
			}
			if($this->version() > '5.0.1') {
				@mysql_query("SET sql_mode=''", $this->link);
			}
		}
		if($dbname) {
			$this->select_db($dbname);
		}
	}

	//連接一個只讀的mysql數據庫
	function connect_ro($dbhost, $dbuser, $dbpw, $dbname = '', $pconnect = 0){
		if($this->link_rw == null)
			$this->link_rw = $this->link;
		$this->link = null;
		//不產生halt錯誤
		$this->connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect, false);
		if($this->link){
			//連接成功
			//echo "link ro sussess!<br>";
			$this->ro_exist = true;
			$this->link_ro = $this->link;
			if($this->cur_db){
				//如果已經選擇過數據庫則需要操作一次
				@mysql_select_db($this->cur_db, $this->link_ro);
			}
		}else{
			//連接失敗
			//echo "link ro failed!<br>";
			$this->link = &$this->link_rw;
		}
	}

	//設置一系列只讀數據庫並且連接其中一個
	function set_ro_list($ro_list){
		if(is_array($ro_list)){
			//隨機選擇其中一個
			$link_ro = $ro_list[array_rand($ro_list)];
			$this->connect_ro($link_ro['dbhost'], $link_ro['dbuser'], $link_ro['dbpw']);
		}
	}

	function select_db($dbname) {
		//同時操作兩個數據庫連接
		$this->cur_db = $dbname;
		if($this->ro_exist){
			@mysql_select_db($dbname, $this->link_ro);
		}
		return @mysql_select_db($dbname, $this->link_rw);
	}

	function fetch_array($query, $result_type = MYSQL_ASSOC) {
		return mysql_fetch_array($query, $result_type);
	}

	function fetch_one_array($sql, $type = '') {
		$qr = $this->query($sql, $type);
		return $this->fetch_array($qr);
	}

	function query($sql, $type = '') {
		$this->link = &$this->link_rw;
		//判斷是否select語句
		if($this->ro_exist && preg_match ("/^(\s*)select/i", $sql)){
			$this->link = &$this->link_ro;
		}
		$func = $type == 'UNBUFFERED' && @function_exists('mysql_unbuffered_query') ?
			'mysql_unbuffered_query' : 'mysql_query';
		if(!($query = $func($sql, $this->link)) && $type != 'SILENT') {
			$this->halt('MySQL Query Error', $sql);
		}
		$this->querynum++;
		return $query;
	}

	function affected_rows() {
		return mysql_affected_rows($this->link);
	}

	function error() {
		return (($this->link) ? mysql_error($this->link) : mysql_error());
	}

	function errno() {
		return intval(($this->link) ? mysql_errno($this->link) : mysql_errno());
	}

	function result($query, $row) {
		$query = @mysql_result($query, $row);
		return $query;
	}

	function num_rows($query) {
		$query = mysql_num_rows($query);
		return $query;
	}

	function num_fields($query) {
		return mysql_num_fields($query);
	}

	function free_result($query) {
		return mysql_free_result($query);
	}

	function insert_id() {
		return ($id = mysql_insert_id($this->link)) >= 0 ? $id : $this->result($this->query("SELECT last_insert_id()"), 0);
	}

	function fetch_row($query) {
		$query = mysql_fetch_row($query);
		return $query;
	}

	function fetch_fields($query) {
		return mysql_fetch_field($query);
	}

	function version() {
		return mysql_get_server_info($this->link);
	}

	function close() {
		return mysql_close($this->link);
	}

	function halt($message = '', $sql = '') {
		$dberror = $this->error();
		$dberrno = $this->errno();
		echo "<div style=\"position:absolute;font-size:11px;font-family:verdana,arial;background:#EBEBEB;padding:0.5em;\">
				<b>MySQL Error</b><br>
				<b>Message</b>: $message<br>
				<b>SQL</b>: $sql<br>
				<b>Error</b>: $dberror<br>
				<b>Errno.</b>: $dberrno<br>
				</div>";
		exit();
	}
}

?>