mqtt 客戶端

mqtt client class

<?php

namespace App\Servers;

/**
 * Class MqttClient
 * @package App\Servers
 */
class MqttClient
{
    private $socket;            /* holds the socket */
    private $msgid = 1;         /* counter for message id */
    public $keepalive = 10;     /* default keepalive timmer */
    public $timesinceping;      /* host unix time, used to detect disconects */
    public $topics = [];        /* used to store currently subscribed topics */
    public $debug = false;     /* should output debug messages */
    public $address;            /* broker address */
    public $port;               /* broker port */
    public $client_id;          /* client id sent to brocker */
    public $will;               /* stores the will of the client */
    private $username;          /* stores username */
    private $password;          /* stores password */

    public function __construct($address, $port, $client_id = null)
    {
        if (!$client_id) {
            $client_id = uniqid(microtime(true));
        }
        $this->address = $address;
        $this->port = $port;
        $this->client_id = $client_id;
    }

    /**
     * connects to the broker
     *
     * @param bool $clean should the client send a clean session flag
     * @param null $will
     * @param null $username
     * @param null $password
     * @return bool
     */
    public function connect($clean = true, $will = NULL, $username = NULL, $password = NULL)
    {
        if ($will) $this->will = $will;
        if ($username) $this->username = $username;
        if ($password) $this->password = $password;

        $address = gethostbyname($this->address);
        $this->socket = fsockopen($address, $this->port, $errno, $errstr, 60);

        if (!$this->socket) {
            error_log("fsockopen() $errno, $errstr \n");
            return false;
        }

        stream_set_timeout($this->socket, 5);
        stream_set_blocking($this->socket, 0);

        $i = 0;
        $buffer = "";

        $buffer .= chr(0x00);
        $i++;
        $buffer .= chr(0x06);
        $i++;
        $buffer .= chr(0x4d);
        $i++;
        $buffer .= chr(0x51);
        $i++;
        $buffer .= chr(0x49);
        $i++;
        $buffer .= chr(0x73);
        $i++;
        $buffer .= chr(0x64);
        $i++;
        $buffer .= chr(0x70);
        $i++;
        $buffer .= chr(0x03);
        $i++;

        //No Will
        $var = 0;
        if ($clean) $var += 2;

        //Add will info to header
        if ($this->will != NULL) {
            $var += 4; // Set will flag
            $var += ($this->will['qos'] << 3); //Set will qos
            if ($this->will['retain']) $var += 32; //Set will retain
        }

        if ($this->username != NULL) $var += 128; //Add username to header
        if ($this->password != NULL) $var += 64;  //Add password to header

        $buffer .= chr($var);
        $i++;

        //Keep alive
        $buffer .= chr($this->keepalive >> 8);
        $i++;
        $buffer .= chr($this->keepalive & 0xff);
        $i++;

        $buffer .= $this->strwritestring($this->client_id, $i);

        //Adding will to payload
        if ($this->will != NULL) {
            $buffer .= $this->strwritestring($this->will['topic'], $i);
            $buffer .= $this->strwritestring($this->will['content'], $i);
        }

        if ($this->username) $buffer .= $this->strwritestring($this->username, $i);
        if ($this->password) $buffer .= $this->strwritestring($this->password, $i);

        $head = "";
        $head .= chr(0x10);
        $head .= chr($i);

        fwrite($this->socket, $head, 2);
        fwrite($this->socket, $buffer);

        $string = $this->read(4);

        if (ord($string[0]) >> 4 == 2 && $string[3] == chr(0)) {
            if ($this->debug) echo "Connected to Broker\n";
        } else {
            error_log(sprintf("Connection failed! (Error: 0x%02x 0x%02x)\n",
                ord($string[0]), ord($string[3])));
            return false;
        }

        $this->timesinceping = time();

        return true;
    }

    /**
     * reads in so many bytes
     *
     * @param int $int
     * @param bool $nb
     * @return bool|string
     */
    public function read($int = 8192, $nb = false)
    {
        //  print_r(socket_get_status($this->socket));

        $string = "";
        $togo = $int;

        if ($nb) {
            return fread($this->socket, $togo);
        }

        while (!feof($this->socket) && $togo > 0) {
            $fread = fread($this->socket, $togo);
            $string .= $fread;
            $togo = $int - strlen($string);
        }

        return $string;
    }

    /**
     * subscribes to topics
     *
     * @param array $topics
     * @param int $qos
     */
    public function subscribe(array $topics, $qos = 0)
    {
        $i = 0;
        $buffer = "";
        $id = $this->msgid;
        $buffer .= chr($id >> 8);
        $i++;
        $buffer .= chr($id % 256);
        $i++;

        foreach ($topics as $key => $topic) {
            $buffer .= $this->strwritestring($key, $i);
            $buffer .= chr($topic["qos"]);
            $i++;
            $this->topics[$key] = $topic;
        }

        $cmd = 0x80;
        //$qos
        $cmd += ($qos << 1);

        $head = chr($cmd);
        $head .= chr($i);

        fwrite($this->socket, $head, 2);
        fwrite($this->socket, $buffer, $i);
        $string = $this->read(2);

        $bytes = ord(substr($string, 1, 1));
        $string = $this->read($bytes);
    }

    /**
     * sends a keep alive ping
     */
    public function ping()
    {
        $head = chr(0xc0);
        $head .= chr(0x00);
        fwrite($this->socket, $head, 2);
        if ($this->debug) echo "ping sent\n";
    }

    /**
     * sends a proper disconect cmd
     */
    public function disconnect()
    {
        $head = chr(0xe0);
        $head .= chr(0x00);
        fwrite($this->socket, $head, 2);
    }

    /**
     * sends a proper disconect, then closes the socket
     */
    public function close()
    {
        $this->disconnect();
        fclose($this->socket);
    }

    /**
     * publishes $content on a $topic
     *
     * @param $topic
     * @param $content
     * @param int $qos
     * @param int $retain
     */
    public function publish($topic, $content, $qos = 0, $retain = 0)
    {
        $i = 0;
        $buffer = "";

        $buffer .= $this->strwritestring($topic, $i);

        //$buffer .= $this->strwritestring($content,$i);

        if ($qos) {
            $id = $this->msgid++;
            $buffer .= chr($id >> 8);
            $i++;
            $buffer .= chr($id % 256);
            $i++;
        }

        $buffer .= $content;
        $i += strlen($content);

        $cmd = 0x30;
        if ($qos) $cmd += $qos << 1;
        if ($retain) $cmd += 1;

        $head = chr($cmd);
        $head .= $this->setmsglength($i);

        fwrite($this->socket, $head, strlen($head));
        fwrite($this->socket, $buffer, $i);

    }

    /**
     * processes a recieved topic
     *
     * @param $msg
     */
    public function message($msg)
    {
        $tlen = (ord($msg[0]) << 8) + ord($msg[1]);
        $topic = substr($msg, 2, $tlen);
        $msg = substr($msg, ($tlen + 2));
        $found = 0;
        foreach ($this->topics as $key => $top) {
            if (preg_match("/^" . str_replace("#", ".*",
                    str_replace("+", "[^\/]*",
                        str_replace("/", "\/",
                            str_replace("$", '\$',
                                $key)))) . "$/", $topic)) {
                if (is_string($top['function']) && function_exists($top['function'])) {
                    call_user_func($top['function'], $topic, $msg);
                    $found = 1;
                } elseif (is_object($top['function'])) {
                    $top['function']($topic, $msg);
                }
            }
        }

        if ($this->debug && !$found) echo "msg recieved but no match in subscriptions\n";
    }

    /**
     * the processing loop for an "allways on" client
     *
     * @param bool $loop set true when you are doing other stuff in the loop good for watching something else at the same time
     * @return int
     */
    public function proc($loop = true)
    {
        for (; ;) {
            $sockets = array($this->socket);
            $w = $e = NULL;
            $cmd = 0;

            //$byte = fgetc($this->socket);
            if (feof($this->socket)) {
                if ($this->debug) echo "eof receive going to reconnect for good measure\n";
                fclose($this->socket);
                $this->connect(false);
                if (count($this->topics))
                    $this->subscribe($this->topics);
            }

            $byte = $this->read(1, true);

            if (!strlen($byte)) {
                if ($loop) {
                    usleep(100000);
                }

            } else {

                $cmd = (int)(ord($byte) / 16);
                if ($this->debug) echo "Recevid: $cmd\n";

                $multiplier = 1;
                $value = 0;
                do {
                    $digit = ord($this->read(1));
                    $value += ($digit & 127) * $multiplier;
                    $multiplier *= 128;
                } while (($digit & 128) != 0);

                if ($this->debug) echo "Fetching: $value\n";

                if ($value)
                    $string = $this->read($value, "fetch");

                if ($cmd) {
                    switch ($cmd) {
                        case 3:
                            $this->message($string);
                            break;
                    }

                    $this->timesinceping = time();
                }
            }

            if ($this->timesinceping < (time() - $this->keepalive)) {
                if ($this->debug) echo "not found something so ping\n";
                $this->ping();
            }

            if ($this->timesinceping < (time() - ($this->keepalive * 2))) {
                if ($this->debug) echo "not seen a package in a while, disconnecting\n";
                fclose($this->socket);
                $this->connect(false);
                if (count($this->topics))
                    $this->subscribe($this->topics);
            }
        }
        return 1;
    }

    /**
     * get message length
     *
     * @param $msg
     * @param $i
     * @return float|int
     */
    public function getmsglength(&$msg, &$i)
    {

        $multiplier = 1;
        $value = 0;
        do {
            $digit = ord($msg[$i]);
            $value += ($digit & 127) * $multiplier;
            $multiplier *= 128;
            $i++;
        } while (($digit & 128) != 0);

        return $value;
    }

    /**
     * set message length
     *
     * @param $len
     * @return string
     */
    public function setmsglength($len)
    {
        $string = "";
        do {
            $digit = $len % 128;
            $len = $len >> 7;
            // if there are more digits to encode, set the top bit of this digit
            if ($len > 0)
                $digit = ($digit | 0x80);
            $string .= chr($digit);
        } while ($len > 0);
        return $string;
    }

    /**
     * writes a string to a buffer
     *
     * @param $str
     * @param $i
     * @return string
     */
    public function strwritestring($str, &$i)
    {
        $len = strlen($str);
        $msb = $len >> 8;
        $lsb = $len % 256;
        $ret = chr($msb);
        $ret .= chr($lsb);
        $ret .= $str;
        $i += ($len + 2);
        return $ret;
    }

    /**
     * print string
     *
     * @param $string
     */
    public function printstr($string)
    {
        $strlen = strlen($string);
        for ($j = 0; $j < $strlen; $j++) {
            $num = ord($string[$j]);
            if ($num > 31)
                $chr = $string[$j]; else $chr = " ";
            printf("%4d: %08b : 0x%02x : %s \n", $j, $num, $num, $chr);
        }
    }
}

• 釋出示例
  $server mqtt伺服器地址，下同
  $port 埠，下同

  <?php
  $mqtt =  new MqttClient($server, $port);
  $mqtt->connect();
  $mqtt->publish('topic', 'hello world!');

• 訂閱示例

  $mqtt =  new MqttClient($server, $port);
  $mqtt->connect();
  //#萬用字元訂閱所有頻道，function可用函式名回撥
  $topics['#'] = [
  "qos" => 0,
  "function" => function ($topic, $message) {
        var_dump($topic, $message);
  }
  }];
  $mqtt->subscribe($topics);
  $mqtt->proc();

本作品採用《CC 協議》，轉載必須註明作者和本文連結