保持MQTT客户端连接始终处于活动状态 [英] Keep a MQTT Client Connection always active
问题描述
我在基于Pub-Sub的应用程序中将CloudMQTT用作MQTT broker.我正在使用publisher通过topic将数据发布到CloudMQTT server，并且我打算subscribe分发到网页上的代理以接收传输的信息.
I am using CloudMQTT as a MQTT broker in my Pub-Sub based application. I am using my publisher to publish data to the CloudMQTT server over a topic, and I plan to subscribe to the broker on my webpage to recieve the transmitted information.
我正在使用此过程创建Client(订户): https://www .cloudmqtt.com/docs-php.html
I am using this procedure to create a Client(subscriber): https://www.cloudmqtt.com/docs-php.html
代码如下:
// subscribe.php
require("phpMQTT.php");
$host = "hostname";
$port = port;
$username = "username";
$password = "password";
$mqtt = new phpMQTT($host, $port, "ClientID".rand());
if(!$mqtt->connect(true,NULL,$username,$password)){
exit(1);
}
//currently subscribed topics
$topics['topic'] = array("qos"=>0, "function"=>"procmsg");
$mqtt->subscribe($topics,0);
while($mqtt->proc()){
}
$mqtt->close();
function procmsg($topic,$msg){
echo "Msg Recieved: $msg";
}
这是phpMQTT.php文件: https://github.com/bluerhinos/phpMQTT/blob/master/phpMQTT.php
但是，在这种情况下，问题在于仅在打开网页时它才接收数据.即使网页未打开时我也要保持连接状态以始终接收已发布的消息，我该怎么办?
However, the issue in this case is that it recieves data only when the webpage is open.. I want to keep the connection alive even if the webpage is not open to always recieve published messages, how can I do it?
如果有人可以推荐一些替代方法，我可能会愿意使用服务器上的其他技术来处理此订阅过程
EDIT : I might be open to using some other technology on the server to handle this subscription process, if anyone can recommend some alternatives
推荐答案
PHP的典型操作模式是启动进程，等待HTTP连接，处理请求，然后启动新进程.这与具有长时间运行的流程的典型MQTT模式不太吻合.因此，当您关闭网页时，将关闭MQTT连接.
PHP's typically mode of operation is to start a process, wait for an HTTP connection, handle the request and then start a new process. This doesn't fit well with the typical MQTT mode of having a long-running process; hence closing the MQTT connection when you close the web page.
可以在长时间运行的CLI PHP脚本中订阅MQTT主题，但是您将必须具有其他某种机制来保持进程运行.有很多不同的方法可以执行此操作，具体取决于您的喜好和操作系统:
It is possible to subscribe to a MQTT topic in a long-running CLI PHP script, but you will have to have some other mechanism to keep the process running. There are a lot of different ways of doing this, depending on your preferences and operating system:
- 在系统启动时使用/etc/rc.local启动的脚本
- 使用init.d脚本
- 使用流程管理器，例如DJB的daemontools或runit
- 如果您使用的是Ubuntu，那么新贵是一种流行的机制
搜索stackoverflow会发现以下相关问题和几个答案:
Searching stackoverflow finds the following related question and several answers:
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