How is it possible to send messages from server to client?

[thosaa]

Hi

I was looking into this project as it has support for TCP as written in the README file.
I have connected a client to a server and can send messages and receive answers.

In order to make two-way communication between client and server when the client is behind a NAT or firewall without using (the currently unsupported) websockets, I was looking into sending a message from the server to the client by using the already established session, which should be possible as written in the RFC8323 section 3.3 'Message Transmission':

The Transport Connection is bidirectional, so requests can be sent by
both the entity that established the connection (Connection
Initiator) and the remote host (Connection Acceptor).

I can see that there is a makeRequest() method for the server, but I am missing a corresponding addRequestHandler for the client in order to catch the request made by the server.

Is this functionality supported at the moment?
Or am I missing something obvious?

Thanks

[szysas]

Hi,

Can you provide your code snippet?
I guess your are using CoapClient class, note that it is just a helper adapter over CoapServer class.
What you can do on client side is to first to initialise CoapServer class. Then, if needed, create CoapClient object from it:

    CoapClient client = CoapClientBuilder.clientFor(serverAddress, cnn);

For example: https://github.com/ARMmbed/java-coap/blob/master/coap-core/src/test/java/protocolTests/ClientServerTest.java#L254