Netty代理示例中ctx.write（Unpooled.EMPTY_BUFFER）的用途是什么(What's the purpose of ctx.write(Unpooled.EMPTY_BUFFER) in Netty proxy example)

 Node.js是制作实时框架以将用户链接到RESTful后端的不错选择。 但是，您也可以考虑使用托管实时消息服务（如PubNub）实时在用户和PHP后端之间传递数据。 
 
 使用PubNub的PHP Api ，您可以设置服务器以侦听事件： 
 
$pubnub = new Pubnub(
    "demo",  ## PUBLISH_KEY
    "demo",  ## SUBSCRIBE_KEY
    "",      ## SECRET_KEY
    false    ## SSL_ON?
);
$pubnub->subscribe(array(
    'channel'  => 'hello_world',        ## REQUIRED Channel to Listen
    'callback' => function($message) {  ## REQUIRED Callback With Response
        ## Do all the awesome stuff your server does
        return true;         ## Keep listening (return false to stop)
    }
));
 
 现在您的服务器已订阅您的频道，您也可以让您的客户订阅，以收听全球事件。 我将从JavaScript SDK中给出一个示例，但是每个大型移动平台都有一个SDK： 
 
     var pubnub = PUBNUB.init({
         publish_key   : 'demo',
         subscribe_key : 'demo'
     })

     function publish() {
         pubnub.publish({
             channel : "hello_world",
             message : "Bob added Stan as a friend"
         })
     }
 })();
 
 您也可以反向执行此操作，以将消息从服​​务器广播到客户端。 巴姆！ 
 
 最终，您可能希望为每个用户扩展您的应用程序，以便能够与服务器进行私密通信，以及身份验证; 我们称之为PubNub Access Manager，它受到了很大的支持。 
 
 祝你好运！ 

Node.js is a good choice to make a realtime framework to link your users to your RESTful backend. However, you may also consider using a hosted realtime messaging service such as PubNub to pass data between your users and your PHP backend in real time.
 
Using PubNub’s PHP Api, you can set up your server to listen for events:
 
$pubnub = new Pubnub(
    "demo",  ## PUBLISH_KEY
    "demo",  ## SUBSCRIBE_KEY
    "",      ## SECRET_KEY
    false    ## SSL_ON?
);
$pubnub->subscribe(array(
    'channel'  => 'hello_world',        ## REQUIRED Channel to Listen
    'callback' => function($message) {  ## REQUIRED Callback With Response
        ## Do all the awesome stuff your server does
        return true;         ## Keep listening (return false to stop)
    }
));
 
Now that your server is subscribed to your channel, you can have your clients subscribe as well, to listen for global events. I’m going to give an example from the JavaScript SDK, but there’s an SDK for every sizable mobile platform as well:
 
     var pubnub = PUBNUB.init({
         publish_key   : 'demo',
         subscribe_key : 'demo'
     })

     function publish() {
         pubnub.publish({
             channel : "hello_world",
             message : "Bob added Stan as a friend"
         })
     }
 })();
 
You can also do this in reverse, to broadcast messages from the server to the clients. Bam!
 
Eventually you may want to extend your app with a unique channel for each user to be able to communicate privately with the server, and also authentication; we call this PubNub Access Manager and it is heavily supported.
 
Good luck!