How to send customized ping message on connectionLostTimeout interval

[gharia]

Describe what you would like to know or do
How to send a custom Ping message on connectionLostTimeout?

Describe the solution you'd considered
For creating a WS client, I am extending WebSocketClient. I did setConnectionLostTimeout to 30 seconds. and override the sendPing() method

Java-WebSocket/src/main/java/org/java_websocket/client/WebSocketClient.java

Line 439 in a2c63db

public void sendPing() {

@Override
  public void sendPing() {
    log.info("Sending ping");
    JsonObject pingObj = new JsonObject();
    pingObj.addProperty("id", "NGenerated guid id");
    pingObj.addProperty("type", "ping");
    this.send(pingObj.toString());
  }

I thought it would be simple, just to override sendPing(). But it is not the case. My overridden method never gets invoked. Rather it calls engine's sendPing()

Java-WebSocket/src/main/java/org/java_websocket/WebSocketImpl.java

Line 661 in a2c63db

public void sendPing() {

Additional context
It's not causing any connection close issue, but I am just looking for a way o customize the send ping message.

[marci4]

Hello @gharia,

that is currently not possible!

Best regards,
Marcel

[haruntuncay]

Hello @marci4, I hope you are well and sorry that I wasn't active for a looong time. I would like to start helping again by giving this issue a go, if that's okay ?

[marci4]

Hello @haruntuncay,

doing well, hope you are doing good?
Please don't feel obligated. Just look at my activity currently ;)

Of course, feel free :)

Best regards,
Marcel

[haruntuncay]

@marci4, Can I ask for your advice on something via email ?

[marci4]

@haruntuncay always! :)

[haruntuncay]

Hello @gharia
Could you please clarify whether you want to send a ping frame "with data" or just want to be notified when a ping frame is sent ? The spec allows ping frames to have application data. So in the first case, we can have a way to set ping frame data, but in order to be able to customize the data sent with each ping, more work would be required by the user. For example, we can have another listener method, something like onPingSent for example, and the user would implement it to change the data with each ping.

[gharia]

Thanks @haruntuncay for looking into it. If possible I would like to send the ping frame "with data" as described in the issue details. ould you point to me an example if any?

[haruntuncay]

@gharia, Currently, there isn't any way to set ping frame data, but I'm currently giving it a go. I would probably be able to submit a PR for review in 1-2 days.

[haruntuncay]

@marci4, @gharia, I am uncertain regarding the functionality here. Would support for String data only be enough, or should binary data also be supported ? Also, instead of overwriting sendPing, I was thinking of adding a method called setPingFrameData, since sendPing on WebSocketClient is there just for inheritance, and not actually called.

[gharia]

@haruntuncay I think support for String data is good enough in case of ping, at least from my perspective. It would be rare if someone wants to send binary data frames along with PING.

Re: sendPing on WebSocketClient - Yes that is not being called on ping event. I am not sure what is the purpose of this method in WebSocketClient, because it always invokes the engine's sendPing()

Java-WebSocket/src/main/java/org/java_websocket/WebSocketImpl.java

Line 661 in a2c63db

public void sendPing() {

.

[haruntuncay]

sendPing is there because both WebSocketImpl and WebSocketClient implements WebSocket interface. But WebSocketClient@sendPing could be made final to avoid this confusion.

[marci4]

@haruntuncay I would not limit the data to Strings.
I would simply provide method someone can overwrite, but by default returns new PingFrame().

Maybe extending the WebSocketListener/WebSocketAdapter and providing a default implementation for something like
onPreparePing(WebSocket conn)?

Then sendPing will call onPreparePing() (we have to remove the cached ping frame then).