php如何实现消息推送

<?php
// server.php
header('Content-Type: application/json');

$clients = [];

if (isset($_POST['client_id'])) {
    $clients[$_POST['client_id']] = $_POST;
}

while (true) {
    foreach ($clients as $client_id => $client) {
        if (isset($client['last_message_id'])) {
            // 模拟从数据库获取新消息
            $new_message = getMessageFromDB($client['last_message_id']);
            if ($new_message) {
                echo json_encode(['message' => $new_message]);
                unset($clients[$client_id]);
                break;
            }
        }
    }
    usleep(100000); // 等待100毫秒
}

function getMessageFromDB($last_id) {
    // 模拟从数据库获取消息
    return ['id' => $last_id + 1, 'text' => 'New message'];
}
?>

function longPoll(clientId) {
    fetch('server.php', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({ client_id: clientId, last_message_id: getLastMessageId() })
    })
    .then(response => response.json())
    .then(data => {
        if (data.message) {
            console.log('New message:', data.message);
            updateLastMessageId(data.message.id);
        }
        longPoll(clientId);
    });
}

function getLastMessageId() {
    // 从本地存储获取最后一条消息的ID
    return localStorage.getItem('last_message_id') || 0;
}

function updateLastMessageId(id) {
    // 更新本地存储的最后一条消息的ID
    localStorage.setItem('last_message_id', id);
}

longPoll('client1');

<?php
// websocket_server.php
require 'vendor/autoload.php';

use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;
use Ratchet\Server\IoServer;
use Ratchet\Http\HttpServer;
use Ratchet\WebSocket\WsServer;

class Chat implements MessageComponentInterface {
    protected $clients;

    public function __construct() {
        $this->clients = new \SplObjectStorage;
    }

    public function onOpen(ConnectionInterface $conn) {
        $this->clients->attach($conn);
    }

    public function onMessage(ConnectionInterface $from, $msg) {
        foreach ($this->clients as $client) {
            if ($from !== $client) {
                $client->send($msg);
            }
        }
    }

    public function onClose(ConnectionInterface $conn) {
        $this->clients->detach($conn);
    }

    public function onError(ConnectionInterface $conn, \Exception $e) {
        $conn->close();
    }
}

$server = IoServer::factory(
    new HttpServer(
        new WsServer(
            new Chat()
        )
    ),
    8080
);

$server->run();
?>

const socket = new WebSocket('ws://localhost:8080');

socket.onopen = function() {
    console.log('Connected');
};

socket.onmessage = function(event) {
    console.log('Message from server:', event.data);
};

socket.onclose = function() {
    console.log('Disconnected');
};

socket.onerror = function(error) {
    console.error('WebSocket Error:', error);
};