Examples with NatsClient io.micronaut.nats.annotation.NatsClient used on opensource projects

Example 1 with NatsClient

use of io.micronaut.nats.annotation.NatsClient in project micronaut-nats by micronaut-projects.

the class NatsIntroductionAdvice method intercept.

@Override
public Object intercept(MethodInvocationContext<Object, Object> context) {
    if (context.hasAnnotation(NatsClient.class)) {
        StaticPublisherState publisherState = publisherCache.get(context.getExecutableMethod(), method -> {
            if (!method.findAnnotation(NatsClient.class).isPresent()) {
                throw new IllegalStateException("No @NatsClient annotation present on method: " + method);
            }
            Optional<String> subject = method.findAnnotation(Subject.class).flatMap(AnnotationValue::stringValue);
            String connection = method.findAnnotation(NatsConnection.class).flatMap(conn -> conn.get("connection", String.class)).orElse(NatsConnection.DEFAULT_CONNECTION);
            Argument<?> bodyArgument = findBodyArgument(method).orElseThrow(() -> new NatsClientException("No valid message body argument found for method: " + method));
            Headers methodHeaders = new Headers();
            List<AnnotationValue<MessageHeader>> headerAnnotations = method.getAnnotationValuesByType(MessageHeader.class);
            // set the values in the class first so methods can override
            Collections.reverse(headerAnnotations);
            headerAnnotations.forEach(header -> {
                String name = header.stringValue("name").orElse(null);
                String value = header.stringValue().orElse(null);
                if (StringUtils.isNotEmpty(name) && StringUtils.isNotEmpty(value)) {
                    methodHeaders.put(name, value);
                }
            });
            NatsMessageSerDes<?> serDes = serDesRegistry.findSerdes(bodyArgument).orElseThrow(() -> new NatsClientException(String.format("Could not find a serializer for the body argument of type [%s]", bodyArgument.getType().getName())));
            ReactivePublisher reactivePublisher;
            try {
                reactivePublisher = beanContext.getBean(ReactivePublisher.class, Qualifiers.byName(connection));
            } catch (Throwable e) {
                throw new NatsClientException(String.format("Failed to retrieve a publisher named [%s] to publish messages", connection), e);
            }
            return new StaticPublisherState(subject.orElse(null), bodyArgument, methodHeaders, method.getReturnType(), connection, serDes, reactivePublisher);
        });
        NatsMessage.Builder builder = NatsMessage.builder();
        Headers headers = publisherState.getHeaders();
        Argument[] arguments = context.getArguments();
        Map<String, Object> parameterValues = context.getParameterValueMap();
        for (Argument argument : arguments) {
            AnnotationValue<MessageHeader> headerAnn = argument.getAnnotation(MessageHeader.class);
            boolean headersObject = argument.getType() == Headers.class;
            if (headerAnn != null) {
                Map.Entry<String, List<String>> entry = getNameAndValue(argument, headerAnn, parameterValues);
                String name = entry.getKey();
                List<String> value = entry.getValue();
                headers.put(name, value);
            } else if (headersObject) {
                Headers dynamicHeaders = (Headers) parameterValues.get(argument.getName());
                dynamicHeaders.forEach(headers::put);
            }
        }
        if (!headers.isEmpty()) {
            builder.headers(headers);
        }
        Object body = parameterValues.get(publisherState.getBodyArgument().getName());
        byte[] converted = publisherState.getSerDes().serialize(body);
        builder = builder.data(converted);
        String subject = publisherState.getSubject().orElse(findSubjectKey(context).orElse(null));
        builder = builder.subject(subject);
        if (subject == null) {
            throw new IllegalStateException("No @Subject annotation present on method: " + context.getExecutableMethod());
        }
        Message message = builder.build();
        ReactivePublisher reactivePublisher = publisherState.getReactivePublisher();
        InterceptedMethod interceptedMethod = InterceptedMethod.of(context);
        try {
            boolean rpc = !interceptedMethod.returnTypeValue().isVoid();
            Mono<?> reactive;
            if (rpc) {
                reactive = Mono.from(reactivePublisher.publishAndReply(message)).flatMap(response -> {
                    Object deserialized = deserialize(response, publisherState.getDataType(), publisherState.getDataType());
                    if (deserialized == null) {
                        return Mono.empty();
                    } else {
                        return Mono.just(deserialized);
                    }
                });
                if (interceptedMethod.resultType() == InterceptedMethod.ResultType.SYNCHRONOUS) {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Publish is an RPC call. Blocking until a response is received.", context);
                    }
                } else {
                    if (LOG.isDebugEnabled()) {
                        LOG.debug("Publish is an RPC call. Publisher will complete when a response is received.", context);
                    }
                    reactive = reactive.subscribeOn(scheduler);
                }
            } else {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("Sending the message.", context);
                }
                reactive = Mono.from(reactivePublisher.publish(message)).onErrorMap(throwable -> new NatsClientException(String.format("Failed to publish a message with subject: [%s]", subject), throwable, Collections.singletonList(message)));
            }
            switch(interceptedMethod.resultType()) {
                case PUBLISHER:
                    return interceptedMethod.handleResult(reactive);
                case COMPLETION_STAGE:
                    CompletableFuture<Object> future = new CompletableFuture<>();
                    reactive.subscribe(new Subscriber<Object>() {

                        Object value = null;

                        @Override
                        public void onSubscribe(Subscription s) {
                            s.request(1);
                        }

                        @Override
                        public void onNext(Object o) {
                            value = o;
                        }

                        @Override
                        public void onError(Throwable t) {
                            future.completeExceptionally(t);
                        }

                        @Override
                        public void onComplete() {
                            future.complete(value);
                        }
                    });
                    return interceptedMethod.handleResult(future);
                case SYNCHRONOUS:
                    return interceptedMethod.handleResult(reactive.block());
                default:
                    return interceptedMethod.unsupported();
            }
        } catch (Exception e) {
            return interceptedMethod.handleException(e);
        }
    } else {
        return context.proceed();
    }
}