<?php
ini_set("memory_limit", "128M");
/**
 * redis 服务端 
 * 多进程阻塞式
 * redis-benchmark -h 127.0.0.1 -p 11211 -t set -n 80000 -q
 * 
 * @version 2.7.0
 * @copyright 1997-2018 The PHP Group
 * @author seatle <seatle@foxmail.com> 
 * @created time :2018-01-03
 */
class cls_redis_server
{
    private $socket = false;
    private $process_num = 3;
    public $redis_kv_data = array();
    public $onMessage = null;

    public function __construct($host="0.0.0.0", $port=6379)
    {
        $this->socket = stream_socket_server("tcp://".$host.":".$port,$errno, $errstr);
        if (!$this->socket) die($errstr."--".$errno);
        echo "listen $host $port \r\n";
    }

    private function parse_resp(&$conn)
    {
        // 读取一行，遇到 \r\n 为一行
        $line = fgets($conn);
        if($line === '' || $line === false)
        {
            return null;
        }
        // 获取第一个字符作为类型
        $type = $line[0];
        // 去掉第一个字符，去掉结尾的 \r\n
        $line = mb_substr($line, 1, -2);
        switch ( $type )
        {
        case "*":
            // 得到长度
            $count = (int) $line;
            $data = array();
            for ($i = 1; $i <= $count; $i++) 
            {
                $data[] = $this->parse_resp($conn);
            }
            return $data;
        case "$":
            if ($line == '-1') 
            {
                return null;
            }
            // 截取的长度要加上 \r\n 两个字符
            $length = $line + 2;
            $data = '';
            while ($length > 0) 
            {
                $block = fread($conn, $length);
                if ($length !== strlen($block)) 
                {
                    throw new Exception('RECEIVING');
                }
                $data .= $block;
                $length -= mb_strlen($block);
            }
            return mb_substr($data, 0, -2);
        }
        return $line;
    }

    private function start_worker_process()
    {
        $pid = pcntl_fork();
        switch ($pid) 
        {
        case -1:
            echo "fork error : {$i} \r\n";
            exit;
        case 0:
            while ( true ) 
            {
                echo  "PID ".posix_getpid()." waiting...\n";
                // 堵塞等待
                $conn = stream_socket_accept($this->socket, -1);
                if ( !$conn )
                {
                    continue;
                }
                //"*3\r\n$3\r\nSET\r\n$5\r\nmykey\r\n$7\r\nmyvalue\r\n"
                while( true )
                {
                    $arr = $this->parse_resp($conn);
                    if ( is_array($arr) ) 
                    {
                        if ($this->onMessage) 
                        {
                            call_user_func($this->onMessage, $conn, $arr);
                        }
                    }
                    else if ( $arr )
                    {
                        if ($this->onMessage) 
                        {
                            call_user_func($this->onMessage, $conn, $arr);
                        }
                    }
                    else
                    {
                        fclose($conn);
                        break;
                    }
                }
            }
        default:
            $this->pids[$pid] = $pid;
            break;
        }
    }

    public function run()
    {
        for($i = 1; $i <= $this->process_num; $i++)
        {
            $this->start_worker_process();
        }

        while( true )
        {
            foreach ($this->pids as $i => $pid) 
            {
                if($pid) 
                {
                    $res = pcntl_waitpid($pid, $status,WNOHANG);

                    if ( $res == -1 || $res > 0 )
                    {
                        $this->start_worker_process();
                        unset($this->pids[$pid]);
                    }
                }
            }
            sleep(1);
        }
    }

}

$server = new cls_redis_server();
$server->onMessage = function($conn, $info) use($server)
{
    if ( is_array($info) )
    {
        $command = strtoupper($info[0]);
        if ( $command == "SET" )
        {
            $key = $info[1];
            $val = $info[2];
            $server->redis_kv_data[$key] = $val;
            fwrite($conn, "+OK\r\n");
        }
        else if ( $command == "GET" )
        {
            $key = $info[1];
            $val = isset($server->redis_kv_data[$key]) ? $server->redis_kv_data[$key] : '';
            fwrite($conn, "$".strlen($val)."\r\n".$val."\r\n");
        }
        else
        {
            fwrite($conn,"+OK\r\n");
        }
    }
    else
    {
        fwrite($conn,"+OK\r\n");
    }
};
$server->run();