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javamicronaut

HttpClient throws exception on response code 404. Is this by design or am I doing something wrong?

I am starting today with Micronaut. I built this controller:

@Controller
public class MyController implements MyApi{

@Override
public String doit() {
    throw new NotFoundException();
    }
}

and this exception handler:

@Produces
@Singleton
@Requires(classes = { NotFoundException.class, ExceptionHandler.class})
public class NotFoundExceptionHandler implements ExceptionHandler<NotFoundException, HttpResponse> {

    @Override
    public HttpResponse handle(HttpRequest request, NotFoundException exception) {
        return HttpResponseFactory.INSTANCE.status(HttpStatus.NOT_FOUND);
    }
}

And this test:

@MicronautTest
public class MyControllerIT {

@Inject
@Client("/")
HttpClient client;

@Test
public void testHello() {
    HttpRequest<String> request = HttpRequest.GET("/myController");
    HttpResponse<String> body = client.toBlocking().exchange(request);

    assertThat(body.getStatus(), is(HttpStatus.NOT_FOUND));
    }
}

My expectation is that it would pass: I would get a response back with no content, HTTP code 404, message "Not found" and I would be done.

But, instead, I get:

io.micronaut.http.client.exceptions.HttpClientResponseException: Not Found

at io.micronaut.http.client.DefaultHttpClient$10.channelRead0(DefaultHttpClient.java:1799)
at io.micronaut.http.client.DefaultHttpClient$10.channelRead0(DefaultHttpClient.java:1739)
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.micronaut.http.netty.stream.HttpStreamsHandler.channelRead(HttpStreamsHandler.java:185)
at io.micronaut.http.netty.stream.HttpStreamsClientHandler.channelRead(HttpStreamsClientHandler.java:180)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:438)
at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:328)
at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:302)
at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:253)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:287)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1421)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:930)
at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:697)
at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:632)
at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:549)
at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:511)
at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:918)
at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
at java.base/java.lang.Thread.run(Thread.java:834)

I found this HttpClientResponseException documentation that describes An exception that occurs when a response returns an error code equal to or greater than 400.

Is this really the expected behavior? It seems a little bit odd that it forces me to handle it as an exception when the error code > 400.

Did I do something wrong in my setup?

Solution

  • I don't think there's something wrong with your code. The documentation of this particular exception states clearly:

    An exception that occurs when a response returns an error code equal to or greater than 400.

    If that's not satisfactory for you, we can dig deeper. The exception is thrown in DefaultHttpClient class in a method named channelRead0. Let's see what can we find there.

    boolean errorStatus = statusCode >= 400;
if (errorStatus) {
    emitter.onError(new HttpClientResponseException(response.getStatus().getReason(), response));
} else {
    emitter.onNext(response);
    emitter.onComplete();
}

    This exception is passed further and it looks like it's eventually thrown somewhere. It just works this way, this is the author's design. If you don't like it, you can always use good old built-in HttpURLConnection, a new HttpClient from Java 9 or something 3rd party like OkHttp.