memche消息隊列的原理就是在key上做文章，用以做一個連續(xù)的數(shù)字加上前綴記錄序列化以后消息或者日志。然后通過定時程序?qū)?nèi)容落地到文件或者數(shù)據(jù)庫。
php實現(xiàn)消息隊列的用處比如在做發(fā)送郵件時發(fā)送大量郵件很費時間的問題，那么可以采取隊列。
方便實現(xiàn)隊列的輕量級隊列服務器是：
starling支持memcache協(xié)議的輕量級持久化服務器
https://github.com/starling/starling
Beanstalkd輕量、高效，支持持久化，每秒可處理3000左右的隊列
http://kr.github.com/beanstalkd/
php中也可以使用memcache/memcached來實現(xiàn)消息隊列。
復制代碼 代碼如下:
<?php
/**
* Memcache 消息隊列類
*/
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 計數(shù)器,增加計數(shù)并返回新的計數(shù)
* @param string $key 計數(shù)器
* @param int $offset 計數(shù)增量,可為負數(shù).0為不改變計數(shù)
* @param int $time 時間
* @return int/false 失敗是返回false,成功時返回更新計數(shù)器后的計數(shù)
*/
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;
}
/**
* 寫入隊列
* @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 );
}
/**
* 讀取隊列里的數(shù)據(jù)
* @param string $key
* @param int $max 最多讀取條數(shù)
* @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 );//讀指針
$w_p = self::set_counter( $w_key, 0 );//寫指針
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 );//寫入隊列
$list = QMC::output($key);//讀取隊列
*/
?>
基于PHP共享內(nèi)存實現(xiàn)的消息隊列:
復制代碼 代碼如下:
<?php
/**
* 使用共享內(nèi)存的PHP循環(huán)內(nèi)存隊列實現(xiàn)
* 支持多進程, 支持各種數(shù)據(jù)類型的存儲
* 注: 完成入隊或出隊操作,盡快使用unset(), 以釋放臨界區(qū)
*
* @author wangbinandi@gmail.com
* @created 2009-12-23
*/
class ShmQueue
{
private $maxQSize = 0; // 隊列最大長度
private $front = 0; // 隊頭指針
private $rear = 0; // 隊尾指針
private $blockSize = 256; // 塊的大小(byte)
private $memSize = 25600; // 最大共享內(nèi)存(byte)
private $shmId = 0;
private $filePtr = './shmq.ptr';
private $semId = 0;
public function __construct()
{
$shmkey = ftok(__FILE__, 't');
$this->shmId = shmop_open($shmkey, "c", 0644, $this->memSize );
$this->maxQSize = $this->memSize / $this->blockSize;
// 申?一個信號量
$this->semId = sem_get($shmkey, 1);
sem_acquire($this->semId); // 申請進入臨界區(qū)
$this->init();
}
private function init()
{
if ( file_exists($this->filePtr) ){
$contents = file_get_contents($this->filePtr);
$data = explode( '|', $contents );
if ( isset($data[0]) && isset($data[1])){
$this->front = (int)$data[0];
$this->rear = (int)$data[1];
}
}
}
public function getLength()
{
return (($this->rear - $this->front + $this->memSize) % ($this->memSize) )/$this->blockSize;
}
public function enQueue( $value )
{
if ( $this->ptrInc($this->rear) == $this->front ){ // 隊滿
return false;
}
$data = $this->encode($value);
shmop_write($this->shmId, $data, $this->rear );
$this->rear = $this->ptrInc($this->rear);
return true;
}
public function deQueue()
{
if ( $this->front == $this->rear ){ // 隊空
return false;
}
$value = shmop_read($this->shmId, $this->front, $this->blockSize-1);
$this->front = $this->ptrInc($this->front);
return $this->decode($value);
}
private function ptrInc( $ptr )
{
return ($ptr + $this->blockSize) % ($this->memSize);
}
private function encode( $value )
{
$data = serialize($value) . "__eof";
echo '';
echo strlen($data);
echo '';
echo $this->blockSize -1;
echo '';
if ( strlen($data) > $this->blockSize -1 ){
throw new Exception(strlen($data)." is overload block size!");
}
return $data;
}
private function decode( $value )
{
$data = explode("__eof", $value);
return unserialize($data[0]);
}
public function __destruct()
{
$data = $this->front . '|' . $this->rear;
file_put_contents($this->filePtr, $data);
sem_release($this->semId); // 出臨界區(qū), 釋放信號量
}
}
/*
// 進隊操作
$shmq = new ShmQueue();
$data = 'test data';
$shmq->enQueue($data);
unset($shmq);
// 出隊操作
$shmq = new ShmQueue();
$data = $shmq->deQueue();
unset($shmq);
*/
?>
對于一個很大的消息隊列，頻繁進行進行大數(shù)據(jù)庫的序列化 和 反序列化，有太耗費。下面是我用PHP 實現(xiàn)的一個消息隊列，只需要在尾部插入一個數(shù)據(jù)，就操作尾部，不用操作整個消息隊列進行讀取，與操作。但是，這個消息隊列不是線程安全的，我只是盡量的避免了沖突的可能性。如果消息不是非常的密集，比如幾秒鐘才一個，還是可以考慮這樣使用的。
如果你要實現(xiàn)線程安全的，一個建議是通過文件進行鎖定，然后進行操作。下面是代碼：
代碼如下:
復制代碼 代碼如下:
class Memcache_Queue
{
private $memcache;
private $name;
private $prefix;
function __construct($maxSize, $name, $memcache, $prefix = "__memcache_queue__")
{
if ($memcache == null) {
throw new Exception("memcache object is null, new the object first.");
}
$this->memcache = $memcache;
$this->name = $name;
$this->prefix = $prefix;
$this->maxSize = $maxSize;
$this->front = 0;
$this->real = 0;
$this->size = 0;
}
function __get($name)
{
return $this->get($name);
}
function __set($name, $value)
{
$this->add($name, $value);
return $this;
}
function isEmpty()
{
return $this->size == 0;
}
function isFull()
{
return $this->size == $this->maxSize;
}
function enQueue($data)
{
if ($this->isFull()) {
throw new Exception("Queue is Full");
}
$this->increment("size");
$this->set($this->real, $data);
$this->set("real", ($this->real + 1) % $this->maxSize);
return $this;
}
function deQueue()
{
if ($this->isEmpty()) {
throw new Exception("Queue is Empty");
}
$this->decrement("size");
$this->delete($this->front);
$this->set("front", ($this->front + 1) % $this->maxSize);
return $this;
}
function getTop()
{
return $this->get($this->front);
}
function getAll()
{
return $this->getPage();
}
function getPage($offset = 0, $limit = 0)
{
if ($this->isEmpty() || $this->size < $offset) {
return null;
}
$keys[] = $this->getKeyByPos(($this->front + $offset) % $this->maxSize);
$num = 1;
for ($pos = ($this->front + $offset + 1) % $this->maxSize; $pos != $this->real; $pos = ($pos + 1) % $this->maxSize)
{
$keys[] = $this->getKeyByPos($pos);
$num++;
if ($limit > 0 && $limit == $num) {
break;
}
}
return array_values($this->memcache->get($keys));
}
function makeEmpty()
{
$keys = $this->getAllKeys();
foreach ($keys as $value) {
$this->delete($value);
}
$this->delete("real");
$this->delete("front");
$this->delete("size");
$this->delete("maxSize");
}
private function getAllKeys()
{
if ($this->isEmpty())
{
return array();
}
$keys[] = $this->getKeyByPos($this->front);
for ($pos = ($this->front + 1) % $this->maxSize; $pos != $this->real; $pos = ($pos + 1) % $this->maxSize)
{
$keys[] = $this->getKeyByPos($pos);
}
return $keys;
}
private function add($pos, $data)
{
$this->memcache->add($this->getKeyByPos($pos), $data);
return $this;
}
private function increment($pos)
{
return $this->memcache->increment($this->getKeyByPos($pos));
}
private function decrement($pos)
{
$this->memcache->decrement($this->getKeyByPos($pos));
}
private function set($pos, $data)
{
$this->memcache->set($this->getKeyByPos($pos), $data);
return $this;
}
private function get($pos)
{
return $this->memcache->get($this->getKeyByPos($pos));
}
private function delete($pos)
{
return $this->memcache->delete($this->getKeyByPos($pos));
}
private function getKeyByPos($pos)
{
return $this->prefix . $this->name . $pos;
}
}
