grpc-host-intercepter

gistfile1.txt

public class ClientHostInterceptor implements ClientInterceptor {

    private String host;
    
    private static Metadata.Key<String> HOST_HEADER =
        Metadata.Key.of("Host", Metadata.ASCII_STRING_MARSHALLER);

    public ClientHostInterceptor(final String host) {
        this.host = host;
    }

    public String getHost() {
        return host;
    }

    public void setHost(final String host) {
        this.host = host;
    }

    @Override
    public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(final MethodDescriptor<ReqT, RespT> method,
                                                               final CallOptions callOptions, final Channel next) {
        log.info("Intercepted " + method.getFullMethodName());
        ClientCall<ReqT, RespT> call = next.newCall(method, callOptions);

        call = new ForwardingClientCall.SimpleForwardingClientCall<ReqT, RespT>(call) {
            @Override
            public void start(Listener<RespT> responseListener, Metadata headers) {
                if (StringUtils.isNotEmpty(host)) {
                    log.info("Attaching host header. {}", host);
                    headers.put(HOST_HEADER, host);
                }
                super.start(responseListener, headers);
            }
        };
        return call;
    }
}