用PHP实现memcache客户端（续）

时间：2022-12-05 08:03:03

1、说明

睡了一觉，回想了下昨天的代码，发现有些地方写得不好：

  • 出现错误时不必抛出异常，免得打断了正常的执行流程，而是仅仅记录错误信息，把异常交给使用者处理，这样更灵活
  • socket_create, socket_read, socket_write都有可能出现网络错误，有的代码没有去处理这些可能的错误
  • 没有提供关闭连接的函数
  • 创建socket的动作应该放在connect函数中

本次修改除了修正以上不足之外，还增加了delete, incr, decr, stats命令。

本代码根据 memcached协议中文版一文所述内容编写，在本机上测试通过，感谢作者翻译！！

2、代码

class MyMemcacheClient {
private $host;
private $port;
private $socket;
private $error;

public function __construct() {

    }

public function __destruct() {
        $this->close();
    }

/**
 * 获取最后一次的socket错误
 * @return string 最后一次socket错误字符串
 */
public function setSocketError() {
        $errno = socket_last_error($this->socket);
        $this->error = "[$errno]" . socket_strerror($errno);
    }

/**
 * 获取最后一次错误信息;
 * @return string 最后一次错误信息
 */
public function getLastError() {
return $this->error;
    }

/**
 * 链接memcached服务器
 * @param string $host memcached监听的ip
 * @param integer $port memcached监听的端口
 * @return boolean true表示连接成功，false表示连接失败
 */
public function connect($host = '127.0.0.1', $port = 11211) {
        $this->host = $host;
        $this->port = $port;

        $this->socket = socket_create(AF_INET, SOCK_STREAM, SOL_TCP);
if ($this->socket === false) {
            $this->setSocketError();
return false;
        }

        $result = socket_connect($this->socket, $host, $port);
if ($result === false) {
            $this->setSocketError();
return false;
        } else {
return true;
        }
    }

/**
 * 执行set|add|replace命令
 * @param string $cmd 命令(set|add|replace)
 * @param string $key 键
 * @param string $value 值
 * @param nteger $ttl 生存时间
 * @return boolean true for success, false for fail
 */
private function _set_add_replace($cmd, $key, $value, $ttl = 10) {
        $line1 = sprintf("$cmd %s 0 %d %d\r\n", $key, $ttl, strlen($value));
        $line2 = $value . "\r\n";

        $data = $line1 . $line2;

        $result = socket_write($this->socket, $data, strlen($data));
if ($result === false) {
            $this->setSocketError();
return false;
        }

        $response = socket_read($this->socket, 1024, PHP_NORMAL_READ);
/** 读取最后一个 \n 字符 */
        socket_read($this->socket, 1, PHP_BINARY_READ);

if ($response === false) {
            $this->setSocketError();
return false;
        }

/** 操作成功会返回STORED\r\n */
if (!strncmp($response, 'STORED', 6)) {
return true;
        }

return false;
    }

public function set($key, $value, $ttl = 10) {
return $this->_set_add_replace('set', $key, $value, $ttl);
    }

public function add($key, $value, $ttl = 10) {
return $this->_set_add_replace('add', $key, $value, $ttl);
    }

public function replace($key, $value, $ttl = 10) {
return $this->_set_add_replace('replace', $key, $value, $ttl);
    }

/**
 * 获取一个键的值
 * @param string $key 键
 * @return string|boolean 值, false表示没有这个键或者已过期
 */
public function get($key) {
        $data = sprintf("get %s\r\n", $key);

        $result = socket_write($this->socket, $data, strlen($data));
if ($result === false) {
            $this->setSocketError();
return false;
        }

        $line1 = socket_read($this->socket, 1024, PHP_NORMAL_READ);
/** 读取最后一个 \n 字符 */
        socket_read($this->socket, 1, PHP_BINARY_READ);

if ($line1 === false) {
            $this->setSocketError();
return false;
        }

/** 获取成功，第一行返回 VALUE <key> <flags> <bytes>\r\n */
if (!strncmp($line1, "VALUE", 5)) {
            $line1 = rtrim($line1, "\r\n");
            $arr = explode(' ', $line1);
/** 获取数据长度 */
            $dataLen = intval(end($arr));

/** 获取数据 */
            $response = socket_read($this->socket, $dataLen, PHP_BINARY_READ);
/** 读取最后7个字符 \r\nEND\r\n */
            socket_read($this->socket, 7, PHP_BINARY_READ);

if ($response === false) {
                $this->setSocketError();
return false;
            }

return $response;
        } else {
return false;
        }
    }

/**
 * 设置所有的键过期
 * @return boolean success
 */
public function flushAll() {
        $data = "flush_all\r\n";

        $result = socket_write($this->socket, $data, strlen($data));
/** 读取返回结果，固定为 OK\r\n */
        socket_read($this->socket, 4, PHP_BINARY_READ);

return true;
    }

/**
 * 删除一个键
 * @param string $key 键
 * @param integer $delay 延时
 * @return boolean true for success, false for fail
 */
public function delete($key, $delay = 5) {
        $data = sprintf("delete %s %d\r\n", $key, $delay);

        $result = socket_write($this->socket, $data, strlen($data));
if ($result === false) {
            $this->setSocketError();
return false;
        }

        $response = socket_read($this->socket, 20, PHP_NORMAL_READ);
if ($response === false) {
            $this->setSocketError();
return false;
        }

        socket_read($this->socket, 1, PHP_BINARY_READ);
if (!strncmp($response, "DELETED", 7)) {
return true;
        } else {
return false;
        }
    }

/**
 * incr,decr命令的封装
 * @param string $cmd 操作,incr|decr
 * @param string $key 键
 * @param integer $value 增加或减少的值
 * @return boolean|integer 操作失败，返回false，操作成功，返回整数(操作后的值)
 */
private function _incr_decr($cmd, $key, $value) {
        $data = "$cmd $key $value\r\n";

        $result = socket_write($this->socket, $data, strlen($data));
if ($result === false) {
            $this->setSocketError();
return false;
        }

        $response = socket_read($this->socket, 1024, PHP_NORMAL_READ);
if ($response === false) {
            $this->setSocketError();
return false;
        }

        socket_read($this->socket, 1, PHP_BINARY_READ);
if ($response != "NOT_FOUND\r") {
return intval($response);
        } else {
return false;
        }
    }

public function incr($key, $value = 1) {
return $this->_incr_decr("incr", $key, $value);
    }

public function decr($key, $value = 1) {
return $this->_incr_decr("decr", $key, $value);
    }

/**
 * 返回统计信息
 * @return boolean|array 失败，返回false，成功，返回数组，格式 key => value
 */
public function stats() {
        $data = $arg ? "stats $arg\r\n" : "stats\r\n";

        $result = socket_write($this->socket, $data, strlen($data));
if ($result === false) {
            $this->setSocketError();
return false;
        }

        $stats = [];
while(true) {
            $line = socket_read($this->socket, 1024, PHP_NORMAL_READ);
if (false === $line) {
break;
            }
if ($line == "END\r") {
                socket_read($this->socket, 1, PHP_BINARY_READ);
break;
            } else {
                $arr = explode(' ', rtrim($line, "\r"));
                $stats[$arr[1]] = $arr[2];

                socket_read($this->socket, 1, PHP_BINARY_READ);
            }
        }

return $stats;
    }

/**
 * 关闭连接
 * @return void 没有返回值
 */
public function close() {
        $this->socket && socket_close($this->socket);
    }
}

3、测试

  • 测试代码
try {
$memcache = new MyMemcacheClient();
if (false === $memcache->connect()) {
        throw new Exception("connect to memcached failed: " . $memcache->getlastError());
    }

$memcache->flushAll();

    echo "a=", $memcache->get("a"), PHP_EOL;

if (false === $memcache->set("a", "This is a")) {
        echo "set a failed: ", $memcache->getLastError(), PHP_EOL;
    } else {
        echo "a: ", $memcache->get("a"), PHP_EOL;
    }

$memcache->set('total', 10, 30);
    echo "total: ", $memcache->get("total"), PHP_EOL;
$memcache->incr("total", 2);
    echo "total: ", $memcache->get("total"), PHP_EOL;
$memcache->decr("total", 1);
    echo "total: ", $memcache->get("total"), PHP_EOL;

if (false === $memcache->delete("total")) {
        echo "delete total failed", PHP_EOL;
    } else {
        echo "delete total success! total: ", $memcache->get("total"), PHP_EOL;
    }

$stats = $memcache->stats();
    foreach($stats as $k => $v) {
        echo $k,": ", $v, PHP_EOL;
    }

$memcache->close();

} catch (Exception $e) {
    echo $e->getMessage();
}
  • 测试结果
a=
a: This is a
total: 10
total: 12
total: 11
delete total success! total: 
pid: 11812
uptime: 2890
time: 1487218922
version: 1.2.6
pointer_size: 32
curr_items: 2
total_items: 60
bytes: 115
curr_connections: 3
total_connections: 33
connection_structures: 4
cmd_get: 154
cmd_set: 60
get_hits: 120
get_misses: 34
evictions: 0
bytes_read: 4196
bytes_written: 8247
limit_maxbytes: 134217728
threads: 1
标签：

相关文章