B4J Question AsyncStreams & client is turned off

[tchart]

I'm developing an app that uses ServerSocket and AsyncStreams.

If my client terminates the stream I get the _Terminated message.

If I turn the client off (ie power device off) I don't get any messages so I dont know that the astream has been terminated.

Is there any way to dtermine if the astream is still connected? Or do I just need to keep track of and manually check the last time data was received?

Thanks

 

[tchart]

For now Im just checking if a previous stream exists when the client reconnects. If there is a previous connection I terminate it.

 

[Erel]

You should also handle the Error event.

 

[tchart]

You should also handle the Error event.

Thanks Erel, I am handling the Error event but if the client disconnected abruptly I get no events firing.

 

[Erel]

This means that the network driver "thinks" that it is still connected. The solution for such cases is to use a timer and send a ping request every few seconds. If there is no response then the connection is broken.

With that said, there are simpler and better solutions. What is the client? How is it implemented?

 

[tchart]

Erel, the client is a UDP/Network device. It creates a socket connection to the nominated server. I was just concerned if the client gets disconnected abruptly and then reconnects with a new socket. I've added code to check if there was a previous connection for the client MAC address which seems to work well to keep connections down.

The problem is that I have a REST API which writes data to the socket. If the client has disconnected I dont know if the write was successful or not. I probably need to do more testing around this to see if the write fails.

This is the device;
http://www.limitlessled.com/shop/wifi-udp-receiver-bridge/

 

[tchart]

Erel, I have done more testing and although astream.Write returns true it does timeout and I get this error which I am now releasing the stream;

Exception=(SocketTimeoutException) java.net.SocketTimeoutException: Read timed out

Is there a way to adjust the socket timeout?

 

[Erel]

The value returned from astream.Write is not relevant. It just means that the queue is not full.

Which code causes this error? Do you see it in Astream_Error sub?

 

[tchart]

Erel, no code as such.

After I call astream.Write (which returns true) there is a delay (timeout period?) and then Astream_Error is called.

 

[Erel]

This delay is not configurable. It is the time that takes the driver to find out that the connection is no longer valid.