Ah okay, I see.
So, in the case I want to perform ping/pong keepalives, the question is:
How can I send a valid PingFrame from the server to the client?
(Seems like I was too cheeky... :-))
However, the Pong chapter in the WebSocket RFC (ch. 5.5.3,
http://www.rfc-editor.org/rfc/rfc6455.txt) says something like:
"A Pong frame MAY be sent unsolicited. This serves as a unidirectional
heartbeat. A response to an unsolicited Pong frame is not expected."
That's exactly what I want to achieve with the client code from my last
snippet. The client shall send heartbeats to the server at a specified
interval.
Consequently, I need to find a way to send valid PongFrames from the client
to the server.
Any hints on this one? :-)
Thanks in advance!
Philipp
**
2012/1/10 Ryan Lubke <ryan.lubke_at_oracle.com>
> On 1/9/12 2:42 PM, Philipp Tarasiewicz wrote:
>
> It turned out that I still have complications to send a valid PongFrame
> while implementing a heart-beat mechanism on my websocket client.
>
> Here is the relevant snippet:
>
> // My WebSocketApplication subclass
>
> @Override
> public void onPong(WebSocket socket, byte[] bytes) {
> System.out.println("*** *** onPong() *** ***");
> super.onPong(socket, bytes);
> }
>
> // My client's PongFrame send invocation
> webSocket.send(new DataFrame(new PongFrameType(), new byte[0],
> true).getBytes());
>
> That's not going to work since the binary representation of the frame you
> create will be the payload and not the frame itself.
>
> If the Server is sending the ping, the pong should be sent automatically
> so you shouldn't have to do this.
>
>
> Syntax highlighted version:
> http://pastebin.com/ADSGKBxS
>
>
> All I want to accomplish is to let the client send a valid PongFrame, such
> that my overriden onPong() callback gets invoked on the server side.
>
> Would you be so kind and provide a snippet showing a sending of a valid
> PongFrame? :-)
>
> 2012/1/9 Philipp Tarasiewicz <justphilmusic_at_googlemail.com>
>
>> Hi Ryan,
>>
>> I haven't any code that is worth mentioning, since I've obviously
>> misinterpreted the related API docs.
>>
>> My initial thoughts after having studied the docs were like:
>> Grizzly automatically performs ping/pong cycles every x seconds to
>> maintain the connection to every connected remote client and
>> correspondingly invokes the related callback methods in the
>> WebSocketApplication class.
>> - onPing(WebSocket socket, byte[] bytes) : Server is about to ping
>> WebSocket 'socket' by sending 'bytes' bytes.
>> - onPong(WebSocket socket, byte[] bytes) : Server has received pong
>> information 'bytes' from remote client connected to WebSocket 'socket'.
>>
>> So, I've overriden these methods in my WebSocketApplication subclass
>> (just for logging purpose), started the server, connected a client to it
>> and have been expecting that server/client will automatically perform
>> ping/pong cycles every x seconds.
>>
>>
>> But finally, after having read your and Justin's responses + having a
>> closer look at your corresponding code (just cloned the repo), it is
>> completely enlightening that it could not work this way.
>>
>> In particular, I've realized how you send the ping / pong frames.
>> Consequently, it shouldn't be a big deal for me to implement the behavior
>> that I had initially expected.
>>
>> Nevertheless, I will also log a feature request. :-)
>>
>>
>>
>> There is one more question I'm interested in. But, I should probably ask
>> it in a new thread since it does not related to this topic.
>>
>> Thank you guys for your help!
>>
>> Phil
>>
>>
>> 2012/1/9 Ryan Lubke <ryan.lubke_at_oracle.com>
>>
>>> On 1/9/12 7:19 AM, justphilmusic_at_googlemail.com wrote:
>>>
>>>> Hi Ryan!
>>>>
>>>> Until now I've just played around with the WebSocketClient included in
>>>> Grizzly's 2.1.8 WebSocket API. So, it's the websocket version that the
>>>> WebSocketClient class is using.
>>>> I haven't used a brower yet.
>>>>
>>> To go back to your original question, I've locally tested that pings are
>>> responded to automatically, however, I'm making some changes to
>>> make sending pings a little more straight forward.
>>>
>>> Can you share your code? Would like to see what you're doing
>>> different.
>>>
>>>
>>>> The question is:
>>>> Does Grizzly's WebSocket implementation perform any connection
>>>> maintainance / heart-beating under the hood or do I have to implement
>>>> the logic by myself?
>>>>
>>> At this point, there is no heart-beat feature. However, it probably
>>> wouldn't
>>> be a bad feature to offer. I would recommend logging a feature request.
>>>
>>>
>>>>
>>>> Best regards,
>>>> Phil
>>>>
>>>
>>>
>>
>
>