PHP实现的服务器一致性hash分布算法示例

　　本文实例讲述了PHP实现的服务器一致性hash分布算法。分享给大家供大家参考，具体如下：

　　 <?php /** * 对服务器进行一致性hash分布算法 */ class HashRing { private $servers = array(); private $nodeList = array(); private $nodeHashList = array(); private $nodeTotalNum = 0; private $virtualNodeNum = 32; private $keyHash = ; public function __construct($servers) { $this->servers = $servers; foreach ($servers as $server) { for ($i = 0; $i < $this->virtualNodeNum; $i++) { $this->nodeList[sprintf(%u, crc32($server.-.$i))] = array($server, $i); } } ksort($this->nodeList); $this->nodeHashList = array_keys($this->nodeList); } private function getNodeIndex($key) { $this->keyHash = sprintf(%u, crc32($key)); if ($this->keyHash > end($this->nodeHashList)) { $this->keyHash = $this->keyHash % end($this->nodeHashList); } if ($this->keyHash <= reset($this->nodeHashList)) { return 0; } $this->nodeTotalNum = count($this->nodeHashList); return $this->binaryChopIndex(0, $this->nodeTotalNum); } private function binaryChopIndex($l=0, $r=0) { if ($l < $r) { $avg = intval(($l+$r) / 2); if ($this->nodeHashList[$avg] == $this->keyHash) { return $avg; } elseif ($this->keyHash < $this->nodeHashList[$avg] && ($avg > 0)) { return $this->binaryChopIndex($l, $avg-1); } else { return $this->binaryChopIndex($avg+1, $r); } } else { return $l; } } public function getServersByKey($key, $num=1) { $index = $this->getNodeIndex($key); $server = $this->nodeList[$this->nodeHashList[$index]]; if ($num == 1) { return $server[0]; } if ($num >= count($this->servers)) { $num = count($this->servers); } $result = array($server[0]); for ($i=$index+1; true; $i++) { if ($i >= $this->nodeTotalNum) { $i = 0; } $nextServer = $this->nodeList[$this->nodeHashList[$i]]; if (!in_array($nextServer[0], $result)) { $result[] = $nextServer[0]; } if (count($result) == $num) { break; } } return $result; } } //示例 $servers = array( 127.0.0.1:11211, 127.0.0.1:11212, 127.0.0.1:11213, 127.0.0.1:11214, 127.0.0.1:11215 ); $obj = new HashRing($servers); $servers = $obj->getServersByKey(testkey, 2); print_r($servers); echo \n;

　　运行结果：

　　Array
(
[0] => 127.0.0.1:11214
[1] => 127.0.0.1:11211
)

　　PS：这里再为大家提供2款hash相关在线工具供大家参考使用：

　　在线散列/哈希算法加密工具：

　　在线MD5/hash/SHA-1/SHA-2/SHA-256/SHA-512/SHA-3/RIPEMD-160加密工具：

　　更多关于PHP相关内容感兴趣的读者可查看本站专题：《php加密方法总结》、《PHP编码与转码操作技巧汇总》、《PHP数学运算技巧总结》、《PHP数组(Array)操作技巧大全》、《php字符串(string)用法总结》、《PHP数据结构与算法教程》、《php程序设计算法总结》及《php正则表达式用法总结》

　　希望本文所述对大家PHP程序设计有所帮助。