如何在PHP中实现事件监听 [英] How to implement event listening in PHP
问题描述
这里是我的问题：我有一个脚本（让我们称之为comet.php）由AJAX客户端脚本要求，并等待发生如下变化：
while（no_changes）{
usleep（100000）;
//检查更改
}
很多，它不是很可扩展，它是（imho）坏实践
我想用信号量（？）或任何方式改进这种行为并发编程
技术。你能给我一些提示如何处理这个？ （我知道，这不是一个简短的答案，但起点是足够了。）
编辑：关于LibEvent ？
您可以使用 ZeroMQ 解决此问题。
ZeroMQ是一个库提供了用于将事物（线程，进程甚至单独的机器）插入在一起的超级插座。
我假设您正在尝试将数据从服务器推送到客户端。那么，一个很好的方法是使用 EventSource API （ polyfills可用）。
client.js
通过EventSource连接到stream.php。
var stream = new EventSource（'stream.php'）;
stream.addEventListener（'debug'，function（event）{
var data = JSON.parse（event.data）;
console.log（[event.type， data]）;
}）;
stream.addEventListener（'message'，function（event）{
var data = JSON.parse（event.data）;
console.log（[event.type， data]）;
}）;
router.php
这是一个长时间运行的进程，监听收到的消息，并将其发送给任何正在侦听的消息。
？php
$ context = new ZMQContext（）;
$ pull = $ context-> getSocket（ZMQ :: SOCKET_PULL）;
$ pull-> bind（tcp：// *：5555）;
$ pub = $ context-> getSocket（ZMQ :: SOCKET_PUB）;
$ pub-> bind（tcp：// *：5556）;
while（true）{
$ msg = $ pull-> recv（）;
echopublishing received message $ msg \\\
;
$ pub-> send（$ msg）;
}
stream.php
$ b
每个连接到网站的用户都会获得自己的stream.php。此脚本长时间运行，并等待来自路由器的任何消息。一旦收到新邮件，它将以EventSource格式输出此邮件。
<？php
$ context = new ZMQContext（）;
$ sock = $ context-> getSocket（ZMQ :: SOCKET_SUB）;
$ sock-> setSockOpt（ZMQ :: SOCKOPT_SUBSCRIBE，）;
$ sock-> connect（tcp：//127.0.0.1：5556）;
set_time_limit（0）;
ini_set（'memory_limit'，'512M'）;
header（Content-Type：text / event-stream）;
header（Cache-Control：no-cache）;
while（true）{
$ msg = $ sock-> recv（）;
$ event = json_decode（$ msg，true）;
if（isset（$ event ['type']））{
echoevent：{$ event ['type']} \\\
}
$ data = json_encode（$ event ['data']）;
echodata：$ data\\\
\\\
;
ob_flush（）;
flush（）;
}
要向所有用户发送邮件，只需将其发送到路由器。路由器然后将该消息分发到所有监听流。这里有一个例子：
<？php
$ context = new ZMQContext
$ sock = $ context-> getSocket（ZMQ :: SOCKET_PUSH）;
$ sock-> connect（tcp：//127.0.0.1：5555）;
$ msg = json_encode（array（'type'=>'debug'，'data'=> array（'foo'，'bar'，'baz'）））;
$ sock-> send（$ msg）;
$ msg = json_encode（array（'data'=> array（'foo'，'bar'，'baz'）））;
$ sock-> send（$ msg）;
这应该证明你不需要node.js做实时编程。 PHP可以处理它很好。
除此之外，socket.io是一个非常好的方法这样做。
另请参阅
here is my problem: I have a script (let's call it comet.php) whic is requsted by an AJAX client script and wait for a change to happen like this:
while(no_changes){
usleep(100000);
//check for changes
}
I don't like this too much, it's not very scalable and it's (imho) "bad practice" I would like to improve this behaviour with a semaphore(?) or anyway concurrent programming technique. Can you please give me some tips on how to handle this? (I know, it's not a short answer, but a starting point would be enough.)
Edit: what about LibEvent?
You can solve this problem using ZeroMQ.
ZeroMQ is a library that provides supercharged sockets for plugging things (threads, processes and even separate machines) together.
I assume you're trying to push data from the server to the client. Well, a good way to do that is using the EventSource API (polyfills available).
client.js
Connects to stream.php through EventSource.
var stream = new EventSource('stream.php');
stream.addEventListener('debug', function (event) {
var data = JSON.parse(event.data);
console.log([event.type, data]);
});
stream.addEventListener('message', function (event) {
var data = JSON.parse(event.data);
console.log([event.type, data]);
});
router.php
This is a long-running process that listens for incoming messages and sends them out to anyone listening.
<?php
$context = new ZMQContext();
$pull = $context->getSocket(ZMQ::SOCKET_PULL);
$pull->bind("tcp://*:5555");
$pub = $context->getSocket(ZMQ::SOCKET_PUB);
$pub->bind("tcp://*:5556");
while (true) {
$msg = $pull->recv();
echo "publishing received message $msg\n";
$pub->send($msg);
}
stream.php
Every user connecting to the site gets his own stream.php. This script is long-running and waits for any messages from the router. Once it gets a new message, it will output this message in EventSource format.
<?php
$context = new ZMQContext();
$sock = $context->getSocket(ZMQ::SOCKET_SUB);
$sock->setSockOpt(ZMQ::SOCKOPT_SUBSCRIBE, "");
$sock->connect("tcp://127.0.0.1:5556");
set_time_limit(0);
ini_set('memory_limit', '512M');
header("Content-Type: text/event-stream");
header("Cache-Control: no-cache");
while (true) {
$msg = $sock->recv();
$event = json_decode($msg, true);
if (isset($event['type'])) {
echo "event: {$event['type']}\n";
}
$data = json_encode($event['data']);
echo "data: $data\n\n";
ob_flush();
flush();
}
To send messages to all users, just send them to the router. The router will then distribute that message to all listening streams. Here's an example:
<?php
$context = new ZMQContext();
$sock = $context->getSocket(ZMQ::SOCKET_PUSH);
$sock->connect("tcp://127.0.0.1:5555");
$msg = json_encode(array('type' => 'debug', 'data' => array('foo', 'bar', 'baz')));
$sock->send($msg);
$msg = json_encode(array('data' => array('foo', 'bar', 'baz')));
$sock->send($msg);
This should prove that you do not need node.js to do realtime programming. PHP can handle it just fine.
Apart from that, socket.io is a really nice way of doing this. And you could connect to socket.io to your PHP code via ZeroMQ easily.
See also
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