php - 定期向 Ratchet 中的客户端发送消息

Question

我正在尝试定期发送“hello world!”从 Ratchet 教程向所有连接到聊天服务器的客户端发送消息

我将在这里发布所有代码:
聊天.php:

<?php
namespace MyApp;
use Ratchet\MessageComponentInterface;
use Ratchet\ConnectionInterface;

class Chat implements MessageComponentInterface {
    public $clients;

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

    public function onOpen(ConnectionInterface $conn) {
        // Store the new connection to send messages to later
        $this->clients->attach($conn);

        echo "New connection! ({$conn->resourceId})\n";
    }

    //this worked but I don't want this behaviour
    public function onMessage(ConnectionInterface $from, $msg) {
        /*$numRecv = count($this->clients) - 1;
        echo sprintf('Connection %d sending message "%s" to %d other connection%s' . "\n"
            , $from->resourceId, $msg, $numRecv, $numRecv == 1 ? '' : 's');

        foreach ($this->clients as $client) {
            if ($from !== $client) {
                // The sender is not the receiver, send to each client connected
                $client->send($msg);
            }
        }*/
    }

    public function onClose(ConnectionInterface $conn) {
        // The connection is closed, remove it, as we can no longer send it messages
        $this->clients->detach($conn);

        echo "Connection {$conn->resourceId} has disconnected\n";
    }

    public function onError(ConnectionInterface $conn, \Exception $e) {
        echo "An error has occurred: {$e->getMessage()}\n";

        $conn->close();
    }
}

聊天 server.php:

<?php
use Ratchet\Server\IoServer;
use MyApp\Chat;

    require dirname(__DIR__) . '/vendor/autoload.php';

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

    $server->run();

为了测试我理解了多少文档，我在服务器的循环中添加了一个计时器

    <?php
    use Ratchet\Server\IoServer;
    use MyApp\Chat;

        require dirname(__DIR__) . '/vendor/autoload.php';

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


        // My code here
        $server->loop->addPeriodicTimer(5, function () {
          echo  "custom loop timer working !";        
        });


        $server->run();

并且在启动服务器后每五秒输出一次该字符串效果很好。

现在我尝试这样做，尝试向存储在 MessageComponentInterface 中的客户端发送一条消息，该接口(interface)从教程中称为 Chat

$server->loop->addPeriodicTimer(5, function () {        
    foreach ($server->app->clients as $client) {                  
            $client->send("hello client");          
    }
});

但是我得到 $server->app 是 NULL 这可能是因为我现在在 function() 块中。当谈到面向对象的 PHP 时，我不是专家，这个小项目肯定会帮助我很多。
我如何访问 MessageComponentInterface叫 app定时器里面的服务器属性然后将数据发送到存储在那里的客户端？

Answer 1

$server未在函数作用域中定义，并且默认情况下来自父作用域的变量不会继承到子作用域。闭包可以使用 use 从父作用域继承变量。语言结构。

$server->loop->addPeriodicTimer(5, function () use ($server) {        
    foreach ($server->app->clients as $client) {                  
            $client->send("hello client");          
    }
});

有关匿名函数(闭包)的更多信息:https://secure.php.net/manual/en/functions.anonymous.php
更多关于变量作用域的信息:https://secure.php.net/manual/en/language.variables.scope.php