php中利用memcache/memecached构造简单消息队列

性能特点

1. 无差错高并发写入

2.内部指针以int计数, 一个队列当写入次数超过int范围时,出错

 

环境要求:

php + memecached

 

 

以下为php的简单实现

生成环境中可看情况优化

 

 

<?php/** * Memcache 消息队列类 * @author xiaowu <[e-mail]> */class QMC {const PREFIX = 'ASDFASDFFWQKE';/** * 初始化mc * @staticvar string $mc * @return Memcache */static private function mc_init() {static $mc = null;if (is_null($mc)) {$mc = new Memcache;$mc->connect('127.0.0.1', 11211);}return $mc;}/** * mc 计数器,增加计数并返回新的计数 * @param string $key计数器 * @param int $offset计数增量,可为负数.0为不改变计数 * @param int $time时间 * @return int/false失败是返回false,成功时返回更新计数器后的计数 */static public function set_counter( $key, $offset, $time=0 ){$mc = self::mc_init();$val = $mc->get($key);if( !is_numeric($val) || $val < 0 ){$ret = $mc->set( $key, 0, $time );if( !$ret ) return false; $val = 0;}$offset = intval( $offset );if( $offset > 0 ){return $mc->increment( $key, $offset );}elseif( $offset < 0 ){return $mc->decrement( $key, -$offset );}return $val;}/** * 写入队列 * @param string $key * @param mixed $value * @return bool */static public function input( $key, $value ){$mc = self::mc_init();$w_key = self::PREFIX.$key.'W';$v_key = self::PREFIX.$key.self::set_counter($w_key, 1);return $mc->set( $v_key, $value );}/** * 读取队列里的数据 * @param string $key * @param int $max 最多读取条数 * @return array */static public function output( $key, $max=100 ){$out = array();$mc = self::mc_init();$r_key = self::PREFIX.$key.'R';$w_key = self::PREFIX.$key.'W';$r_p = self::set_counter( $r_key, 0 );//读指针$w_p = self::set_counter( $w_key, 0 );//写指针if( $r_p == 0 ) $r_p = 1;while( $w_p >= $r_p ){if( --$max < 0 ) break;$v_key = self::PREFIX.$key.$r_p;$r_p = self::set_counter( $r_key, 1 );$out[] = $mc->get( $v_key );$mc->delete($v_key);}return $out;}}/**使用方法:QMC::input($key, $value );//写入队列$list = QMC::output($key);//读取队列*/?>