PHP+CI框架+Memcache集成

1、目錄結構

 

2、具體代碼

MemcacheCluster.php

<?php

/**
 * 一致性哈希memcache分佈式，採用的是虛擬節點的方式解決分佈均勻性問題,查找節點採用二分法快速查找
 */
class MemcacheCluster
{
    private $_node = array();
    private $_nodeData = array();
    private $_keyNode = 0;
    private $_memcache = null;

    //每一個物理服務器生成虛擬節點個數 [注：節點數越多，cache分佈的均勻性越好，同時set get操做時，也更耗資源，10臺物理服務器，採用200較爲合理]
    private $_virtualNodeNum = 2;

    private function __construct()
    {
        /* 放入配置文件 */
        $config = array(
            '127.0.0.1:11211',
        );

        if (!$config) throw new Exception('Cache config NULL');
        foreach ($config as $key => $value) {
            for ($i = 0; $i < $this->_virtualNodeNum; $i++) {
                $this->_node[sprintf("%u", crc32($value . '_' . $i))] = $value . '_' . $i;
            }
        }
        ksort($this->_node);
    }

    private function __clone()
    {
    }

    /**
     * 單例，保證只有一個實例
     */
    static public function getInstance()
    {
        static $memcacheObj = null;
        if (!is_object($memcacheObj)) {
            $memcacheObj = new self();
        }
        return $memcacheObj;
    }

    /**
     * 根據key作一致性hash後鏈接到一臺物理memcache服務器
     * @param string $key
     */
    private function _connectMemcache($key)
    {
        $this->_nodeData = array_keys($this->_node);
        $this->_keyNode = sprintf("%u", crc32($key));
        $nodeKey = $this->_findServerNode();
        //若是超出環，從頭再用二分法查找一個最近的，而後環的頭尾作判斷，取最接近的節點
        if ($this->_keyNode > end($this->_nodeData)) {
            $this->_keyNode -= end($this->_nodeData);
            $nodeKey2 = $this->_findServerNode();
            if (abs($nodeKey2 - $this->_keyNode) < abs($nodeKey - $this->_keyNode)) $nodeKey = $nodeKey2;
        }
        //var_dump($this->_node[$nodeKey]); 127.0.0.1:11211_20
        list($config, $num) = explode('_', $this->_node[$nodeKey]);
        if (!$config) throw new Exception('Cache config Error');
        if (!isset($this->_memcache[$config])) {
            $this->_memcache[$config] = new Memcache;
            list($host, $port) = explode(':', $config);
            $this->_memcache[$config]->connect($host, $port);
        }
        return $this->_memcache[$config];
    }

    /**
     * 採用二分法從虛擬memcache節點中查找最近的節點
     * @param unknown_type $m
     * @param unknown_type $b
     */
    private function _findServerNode($m = 0, $b = 0)
    {
        $total = count($this->_nodeData);
        if ($total != 0 && $b == 0) $b = $total - 1;
        if ($m < $b) {
            $avg = intval(($m + $b) / 2);
            if ($this->_nodeData[$avg] == $this->_keyNode) return $this->_nodeData[$avg];
            elseif ($this->_keyNode < $this->_nodeData[$avg] && ($avg - 1 >= 0)) return $this->_findServerNode($m, $avg - 1);
            else return $this->_findServerNode($avg + 1, $b);
        }
        if (abs($this->_nodeData[$b] - $this->_keyNode) < abs($this->_nodeData[$m] - $this->_keyNode)) return $this->_nodeData[$b];
        else return $this->_nodeData[$m];
    }

    public function set($key, $value, $expire = 0)
    {
        return $this->_connectMemcache($key)->set($key, json_encode($value), 0, $expire);
    }

    public function add($key, $value, $expire = 0)
    {
        return $this->_connectMemcache($key)->add($key, json_encode($value), 0, $expire);
    }

    public function get($key)
    {
        return json_decode($this->_connectMemcache($key)->get($key), true);
    }

    public function delete($key)
    {
        return $this->_connectMemcache($key)->delete($key);
    }

}

memcached.php

<?php
/**
 * Created by PhpStorm.
 * User: 25754
 * Date: 2019/9/17
 * Time: 16:17
 */

include_once APPPATH . "/third_party/MemcacheCluster.php";

class Memcached
{
    public function set($key, $value, $expire = 0)
    {
        return MemcacheCluster::getInstance()->set($key, $value, $expire);
    }

    public function add($key, $value, $expire = 0)
    {
        return MemcacheCluster::getInstance()->add($key, $value, $expire);
    }

    public function delete($key)
    {
        return MemcacheCluster::getInstance()->delete($key);
    }

    public function get($key)
    {
        return MemcacheCluster::getInstance()->get($key);
    }
}

MY_Controller.php

class Home_Controller extends CI_Controller
{
    public function __construct()
    {
        parent::__construct();
        $this->load->library('memcached', null, 'memcache');
    }
}

index.php

class Index extends Home_Controller
{
    public function __construct()
    {
        parent::__construct();
        $this->load->set_home_view_dir();
    }

    public function index()
    {
        //要設置隨機緩存時間，防止緩存失效，大的訪問量形成數據庫崩潰
        $time = rand(1, 10);
        $key = md5("yy");
        $cacheValue = $this->memcache->get($key);
        if (!$cacheValue) {
            //隨機保存時間
            $flag = $this->memcache->set($key, "yang", $time);
            if ($flag) {
                echo "緩存時間：".$time."秒";
            }
        }
        echo $cacheValue;
    }
}