Client is not registering on Server for Leshan version "2.0.0-M14"

[mhatrepratik11]

Question

Hello Team.

I am new to Leshan and looking for help to start with Leshan. I am trying to implement Leshan Server and Client in my project.

I was following the Github documentation and have implemented Leshan Server and Client with version "1.5.0" which is working fine with each other.

When I tried implementation with version “2.0.0-M14”, my Leshan Client was not able to register onto the server. Whereas, my Leshan Server is working well with the Leshan-Client-Demo JAR file provided in the docs. I am able to register and able to send the data to server using command line.

Leshan Server Code is below:

public class LeshanServerApplication {

	public static void main(String[] args) throws Exception {

		LeshanServerBuilder builder = new LeshanServerBuilder();
		final ThrowingSupplier<URI> uriThrowingSupplier = () -> new URI("COAP", null, "localhost", 5683, null, null, null);

		URI uri = uriThrowingSupplier.get();
		final ServerProtocolProvider serverProtocolProvider = new CoapServerProtocolProvider();
		final CaliforniumServerEndpointFactory californiumServerEndpointFactory = serverProtocolProvider.createDefaultEndpointFactory(uri);
		final Configuration config = new Configuration();
		config.set(CoapConfig.PROTOCOL_STAGE_THREAD_COUNT, 4);
		final CaliforniumServerEndpointsProvider californiumServerEndpointsProvider = new CaliforniumServerEndpointsProvider.Builder(serverProtocolProvider)
			.setConfiguration(config)
			.addEndpoint(californiumServerEndpointFactory)
			.build();
		builder.setEndpointsProviders(californiumServerEndpointsProvider);

		builder.setRegistrationIdProvider(new RandomStringRegistrationIdProvider());
		LeshanServer server = builder.build();

		server.start();

		server.getRegistrationService().addListener(new RegistrationListener() {
			@Override
			public void registered(Registration registration, Registration previousReg, Collection<Observation> previousObservations) {
				System.out.println("Registered client: " + registration.getEndpoint());
			}

			// Other override  methods
		});


		// Starting jetty webserver for UI at http://localhost:8080
		InetSocketAddress jettyAddr = new InetSocketAddress("127.0.0.1", 8080);
		Server jettyServer = new Server(jettyAddr);
		jettyServer.start();
	}
}

There is only issue with server is, I am not able to access web-server to see the UI at http://localhost:8080. I fails with below error:

HTTP ERROR 404 Not Found

URI:	http://localhost:8080/
STATUS:	404
MESSAGE:	Not Found

Leshan Client Code is below:

public class LeshanClientApplication {

	public static void main(String[] args) throws UnknownHostException {

		CaliforniumClientEndpointsProvider.Builder endpointsBuilder = new CaliforniumClientEndpointsProvider.Builder();
		endpointsBuilder.setClientAddress(InetAddress.getLocalHost());

		final LeshanClientBuilder leshanClientBuilder = new LeshanClientBuilder("LwM2M Client");
		Server server = new Server(123, 5L * 60L, EnumSet.of(BindingMode.U), false, BindingMode.U);

		ObjectsInitializer initializer = new ObjectsInitializer();
		initializer.setInstancesForObject(LwM2mId.SECURITY, Security.noSec("coap://127.0.0.1:5683", 123));
		initializer.setInstancesForObject(SERVER, server);
		initializer.setInstancesForObject(LwM2mId.DEVICE, new Device("LwM2M Device 1", "model12345.7", "12345.7", EnumSet.of(BindingMode.U)));
		leshanClientBuilder.setObjects(initializer.createAll());

		final LeshanClient client = leshanClientBuilder
			.setEndpointsProviders(endpointsBuilder.build())
			.build();

		client.start();

		System.out.println("IsRegisteredServers map empty: " + client.getRegisteredServers().isEmpty());

		client.addObserver(new LwM2mClientObserver() {

			@Override
			public void onRegistrationSuccess(LwM2mServer server, RegisterRequest request, String registrationID) {
				System.out.println("onRegistrationSuccess called");
			}

			@Override
			public void onRegistrationTimeout(LwM2mServer server, RegisterRequest request) {
				System.out.println("onRegistrationTimeout called: " + server.getUri() + "    " + server.isLwm2mServer());
				System.out.println("onRegistrationTimeout called with request: " + request.getCoapRequest().toString());
			}

			// Others implemented methods
		});
	}
}

The Leshan Client with above code not able to register itself onto the server. It fails with below error:

01:35:31.511 [RegistrationEngine#0] INFO org.eclipse.leshan.client.engine.DefaultRegistrationEngine -- Trying to register to coap://127.0.0.1:5683 ...
01:35:31.495 [RegistrationEngine#0] INFO org.eclipse.leshan.client.engine.DefaultRegistrationEngine -- Registration failed: Timeout.
onRegistrationTimeout called: coap://127.0.0.1:5683    true
onRegistrationTimeout called with CoAP request: null

Also, "client.getRegisteredServers()" always returns empty map.

Thank you for your attention!

[mhatrepratik11]

I was able to solve client registration issue with below code:

final LeshanClient client = leshanClientBuilder
			.setEndpointsProviders(new CaliforniumClientEndpointsProvider.Builder().build())
			.build();

Setting clientAddress to CaliforniumClientEndpointsProvider was my mistake: "endpointsBuilder.setClientAddress(InetAddress.getLocalHost());"
With this change the client is working fine now.

So now only issue persist is of Leshan WebServer UI is not working at http://localhost:8080
I have added below code for WebServer.

// Starting jetty webserver for UI at http://localhost:8080
InetSocketAddress jettyAddr = new InetSocketAddress("127.0.0.1", 8080);
Server jettyServer = new Server(jettyAddr);
jettyServer.start();

Any suggestions / help would be great.

Thank you for your attention!

[sbernard31]

I looked at your server code and it should rather looks like :

        // create provider
        final CaliforniumServerEndpointsProvider californiumServerEndpointsProvider = new CaliforniumServerEndpointsProvider.Builder(
                new CoapServerProtocolProvider()) //
                        .setConfiguration(config -> config.set(CoapConfig.PROTOCOL_STAGE_THREAD_COUNT, 4))
                        .addEndpoint("coap://localhost:5683") //
                        // OR
                        // .addEndpoint(new InetSocketAddress("localhost", 5683), Protocol.COAP) //
                        .build();

        // create server
        LeshanServerBuilder builder = new LeshanServerBuilder();
        // builder.setRegistrationIdProvider(new RandomStringRegistrationIdProvider()); // not needed used by default
        builder.setEndpointsProviders(californiumServerEndpointsProvider);
        LeshanServer server = builder.build();

        // start it
        server.start();

        // listen for registration
        server.getRegistrationService().addListener(new RegistrationListener() {
            @Override
            public void registered(Registration registration, Registration previousReg,
                    Collection<Observation> previousObservations) {
                System.out.println("Registered client: " + registration.getEndpoint());
            }
            // Other override methods
        });

     // All the jetty code is useless OR it missed your own code to add `Servlet` to jetty.

So now only issue persist is of Leshan WebServer UI is not working at http://localhost:8080/

Leshan is a library, there is no web server UI.
But Leshan provide a standalone demo which contains a web UI.

See FAQ to better understand : https://github.com/eclipse-leshan/leshan/wiki/F.A.Q.#what-is-leshan-and-how-should-i-use-it-
Maybe I should change again the README + FAQ, as it seems not clear for everybody 🤔

[mhatrepratik11]

Thank you very much @sbernard31. Now it's clear to me and thanks for the code. I will change my code accordingly. Satisfied with the answer and good to close this issue. Thanks again...

[sbernard31]

You're welcome.