CODEWITHSUNDEEP
javaspring-bootrestcontroller
Johnny Alpha
Johnny Alpha

Reputation: 970

SpringBoot POST Endpoint returning `No HttpMessageConverter`

I have a task to create a controller with a POST endpoint. The endpoint will take some data as an InputStream. The intent is to process that data and return a stream in the response. The response could be several megabytes in size.

Here's my controller::

@PostMapping(value = "/somePath")
public ResponseEntity<InputStream> processData(final InputStream data) {
    InputStream processed = processor.process(data);
    return ResponseEntity.ok().body(processed);
}

And I'm using the following to test it::

@Autowired RestTemplate restTemplate;

private ResponseEntity<InputStream> request(){

    HttpHeaders headers = new HttpHeaders();
    headers.setAccept(singletonList(APPLICATION_OCTET_STREAM));
    
    ResourceHttpMessageConverter converter = new ResourceHttpMessageConverter();
    converter.setSupportedMediaTypes(Arrays.asList(MediaType.APPLICATION_OCTET_STREAM));
    restTemplate.getMessageConverters().add(converter);

    UriComponentsBuilder builder = fromUriString(format("http://localhost:%s/%s", serverPort, "/somePath"));
    
    UriComponents uriComponents = builder.build().encode(UTF_8);

    HttpEntity<InputStream> entity = new HttpEntity<InputStream>("Hello".getBytes(), headers);

    return restTemplate.exchange(uriComponents.toUri(), HttpMethod.POST, entity, InputStream.class);
}

However, I'm getting ::

org.springframework.web.client.RestClientException: No HttpMessageConverter for [B

I've tried adding a ByteArrayHttpMessageConverter to my RestTemplate, but when I do that I get::

org.springframework.web.client.HttpServerErrorException$InternalServerError: 500 : [<!doctype html><html lang="en"><head><title>HTTP Status 500 – Internal Server Error</title><style type="text/css">body {font-family:Tahoma,Arial,sans-serif;} h1, h2, h3, b {color:white;background-colo... (455 bytes)]

Any help, would be much appreciated!

Upvotes: 0

Views: 341

Answers (1)

Andreas
Andreas

Reputation: 159086

You already fixed the client code by adding a ByteArrayHttpMessageConverter, which makes sense since you're giving it a byte[].

You already know about the ResourceHttpMessageConverter, which is registered by default on the server, so why not use it, i.e. give a Resource as the payload?

Since you have an InputStream, for which there are no message converters by default, use an InputStreamResource:

return ResponseEntity.ok().body(new InputStreamResource(processed));

Upvotes: 1

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