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 教程向连接到聊天服务器的所有客户端发送消息

我将在这里发布所有代码：Chat.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();
    }
}

聊天服务器.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该字符串效果很好。

现在我尝试这样做，尝试向存储在教程中名为 Chat 的 MessageComponentInterface 中的客户端发送消息

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

但我发现 $server->app 为 NULL，这可能是因为我现在位于 function() 块内。在面向对象的 PHP 方面，我不是专家，这个小项目肯定会对我有所帮助很多。如何访问 计时器内服务器的MessageComponentInterface被调用属性，然后将数据发送到存储在其中的客户端？app

Answer 1

$server未在函数作用域中定义，默认情况下，父作用域中的变量不会继承到子作用域。闭包可以使用use语言构造从父作用域继承变量。

$server->loop->addPeriodicTimer(5, function () use ($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
有关变量范围的更多信息： https: //secure.php.net/manual/en/language。变量.scope.php