After upgrade to Spring Integration 6.2.3 from 5.5 the DefaultSftpSessionFactory seems to lose keep alive config methods:

defaultSftpSessionFactory.setServerAliveInterval(keepAliveInterval);
defaultSftpSessionFactory.setServerAliveCountMax(keepAliveCountMax);

With the new version there’s a change from using com.jcraft.jsch to org.apache.sshd.sftp which is responsible for SftpClient configuration

But I struggle to find proper methods to set the properties

What else the new upgrade brought is a warning message about keep alive that I found some suggestions in another SO topic: /a/76907200/1873995 however they don’t work. It relates to https://issues.apache.org/jira/browse/SSHD-1237 but the code was merged to master with no release yet

Warning message:

2024-05-14T10:09:46.686+02:00 WARN 29596 --- [-nio2-thread-12] i.DefaultSftpClient$SftpChannelSubsystem : handleUnknownChannelRequest(SftpChannelSubsystem[id=0, recipient=0]-ClientSessionImpl[[email protected]/123.123.123.22:22][sftp]) Unknown channel request: [email protected][want-reply=true]

I have no clue from where the message is being started and why there’s this address specified: [email protected] as I don’t have it hardcoded anywhere

The suggested code to create custom SshClient and also a suggestion to use a custom DefaultSftpSessionFactory with a handler that’s gonna handled Unknown channel requests but the following code also fails to reach that goal

    @Bean
    public SessionFactory<SftpClient.DirEntry> sftpSessionFactory() {
        SshClient client = customSshClient();

        DefaultSftpSessionFactory factory = new CustomSftpSessionFactory(client, reuseSession);
        factory.setHost(host);
        factory.setPort(port);
        factory.setUser(username);
//        if (keepAliveInterval > 0) { // TODO
//            factory.setServerAliveInterval(keepAliveInterval);
//            factory.setServerAliveCountMax(keepAliveCountMax); 
//        }
        return new CachingSessionFactory<>(factory);
    }

    private SshClient customSshClient() {
        final SshClient client = SshClient.setUpDefaultClient();
        List<RequestHandler<ConnectionService>> oldHandlers = client.getGlobalRequestHandlers();
        List<RequestHandler<ConnectionService>> handlers = new ArrayList<>();
        if (GenericUtils.isNotEmpty(oldHandlers)) {
            handlers.addAll(oldHandlers);
        }
        handlers.add(KeepAliveHandler.INSTANCE);
        client.setGlobalRequestHandlers(handlers);
        client.addPasswordIdentity(password);
        client.setServerKeyVerifier(AcceptAllServerKeyVerifier.INSTANCE);
        return client;
    }

public class CustomSftpSessionFactory extends DefaultSftpSessionFactory {

    public CustomSftpSessionFactory(final SshClient sshClient, final boolean isSharedSession) {
        super(sshClient, isSharedSession);
    }

    @Override
    protected SftpClient createSftpClient(ClientSession clientSession, SftpVersionSelector initialVersionSelector, SftpErrorDataHandler errorDataHandler) throws IOException {
        SftpClient client = super.createSftpClient(clientSession, initialVersionSelector, errorDataHandler);
        client.getSession().setUnknownChannelReferenceHandler(new CustomUnknownChannelReferenceHandler());
//        client.getClientSession().setUnknownChannelReferenceHandler(new CustomUnknownChannelReferenceHandler());

        return client;
    }

    protected class CustomUnknownChannelReferenceHandler implements UnknownChannelReferenceHandler {

        @Override
        public Channel handleUnknownChannelCommand(ConnectionService service, byte cmd, long channelId, Buffer buffer) throws IOException {
            return null;
        }
    }
}

The question is: how to get rid of the warning message and how to setup the keep alive settings?