Spring MVC Rest unable to return JPEG with "could not find acceptable representation error" - spring-mvc

Question

I have a spring-boot app acting as a image server. I POST an image to be persisted to mongodb. I then retrieve it, resize and return it.
Here is the project configuration:
#Configuration
public class AllResources extends WebMvcConfigurerAdapter {
#Override
public void configurePathMatch(PathMatchConfigurer matcher) {
matcher.setUseRegisteredSuffixPatternMatch(true);
}
}
And here is the endpoint:
#RequestMapping(value = "images/{filename}", method = RequestMethod.GET)
#ResponseBody
public ResponseEntity<BufferedImage> getSizedImage(#PathVariable String filename, #RequestParam int width, #RequestParam int height) throws Exception {
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.IMAGE_PNG);
GridFSDBFile savedFile = mongoFileService.getStore( filename );
if ( savedFile != null ) {
try {
BufferedImage image = ImageIO.read( savedFile.getInputStream() );
image = resize( image, Method.SPEED, width, height, Scalr.OP_ANTIALIAS );
LOGGER.info("Returning Filename " + savedFile.getFilename() + " sized to " + width + " X " + height);
return new ResponseEntity<BufferedImage>(image, headers, HttpStatus.OK);
} catch ( Exception ex ) {
ex.printStackTrace();
LOGGER.error( "Error sizing file " + filename + ": " + ex.getMessage() );
return new ResponseEntity<BufferedImage>(null, headers, HttpStatus.INTERNAL_SERVER_ERROR);
}
} else {
LOGGER.error( "Could not find requested file " + filename );
return new ResponseEntity<BufferedImage>(null, headers, HttpStatus.NOT_FOUND);
}
}
The image is retrieved and resized (I can actually preview when debugging in IntelliJ). But when it is returned, I get the following error:
Controller [org.springframework.boot.autoconfigure.web.BasicErrorController]
Method [public org.springframework.http.ResponseEntity<java.util.Map<java.lang.String, java.lang.Object>> org.springframework.boot.autoconfigure.web.BasicErrorController.error(javax.servlet.http.HttpServletRequest)]
org.springframework.web.HttpMediaTypeNotAcceptableException: Could not find acceptable representation
at org.springframework.web.servlet.mvc.method.annotation.AbstractMessageConverterMethodProcessor.writeWithMessageConverters(AbstractMessageConverterMethodProcessor.java:195)
And I see this in the logs:
Method [error] returned [<406 Not Acceptable,{timestamp=Sat Aug 22 11:05:59 MDT 2015, status=406, error=Not Acceptable, exception=org.springframework.web.HttpMediaTypeNotAcceptableException, message=Could not find acceptable representation, path=/images/1440263145562_profile_04132015.PNG},{}>]
2015-08-22 11:05:59.711 DEBUG 2478 --- [0.1-3000-exec-3] o.s.w.s.m.m.a.HttpEntityMethodProcessor : Written [{timestamp=Sat Aug 22 11:05:59 MDT 2015, status=406, error=Not Acceptable, exception=org.springframework.web.HttpMediaTypeNotAcceptableException, message=Could not find acceptable representation, path=/images/1440263145562_profile_04132015.PNG}] as "application/json;charset=UTF-8" using [org.springframework.http.converter.json.MappingJackson2HttpMessageConverter#5bf1ba3a]
2015-08-22 11:05:59.711 DEBUG 2478 --- [0.1-3000-exec-3] o.s.web.servlet.DispatcherServlet : Null ModelAndView returned to DispatcherServlet with name 'dispatcherServlet': assuming HandlerAdapter completed request handling
I have tried with & without the #ResponseBody and it doesn't appear to make a difference either. I have the produces and content type set correctly (I think).
I added these converters (although I thought SpringBoot provided these), but to no avail:
#Configuration
public class AllResources extends WebMvcConfigurerAdapter {
#Override
public void configurePathMatch(PathMatchConfigurer matcher) {
matcher.setUseRegisteredSuffixPatternMatch(true);
}
#Bean
public ByteArrayHttpMessageConverter byteArrayHttpMessageConverter(){
ByteArrayHttpMessageConverter bam = new ByteArrayHttpMessageConverter();
List<org.springframework.http.MediaType> mediaTypes = new LinkedList<MediaType>();
mediaTypes.add(org.springframework.http.MediaType.APPLICATION_JSON);
mediaTypes.add(org.springframework.http.MediaType.IMAGE_JPEG);
mediaTypes.add(org.springframework.http.MediaType.IMAGE_PNG);
mediaTypes.add(org.springframework.http.MediaType.IMAGE_GIF);
mediaTypes.add(org.springframework.http.MediaType.TEXT_PLAIN);
bam.setSupportedMediaTypes(mediaTypes);
return bam;
}
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
MappingJackson2HttpMessageConverter mapper = new MappingJackson2HttpMessageConverter();
converters.add(mapper);
converters.add(byteArrayHttpMessageConverter());
super.configureMessageConverters(converters);
}
}
I hope someone can see what is causing this issue.

Answer 1

Try this piece of code
#RequestMapping("/sparklr/photos/{id}")
public ResponseEntity<BufferedImage> photo(#PathVariable String id) throws Exception {
InputStream photo = sparklrService.loadSparklrPhoto(id);
if (photo == null) {
throw new UnavailableException("The requested photo does not exist");
}
BufferedImage body;
MediaType contentType = MediaType.IMAGE_JPEG;
Iterator<ImageReader> imageReaders = ImageIO.getImageReadersByMIMEType(contentType.toString());
if (imageReaders.hasNext()) {
ImageReader imageReader = imageReaders.next();
ImageReadParam irp = imageReader.getDefaultReadParam();
imageReader.setInput(new MemoryCacheImageInputStream(photo), true);
body = imageReader.read(0, irp);
} else {
throw new HttpMessageNotReadableException("Could not find javax.imageio.ImageReader for Content-Type ["
+ contentType + "]");
}
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.IMAGE_JPEG);
return new ResponseEntity<BufferedImage>(body, headers, HttpStatus.OK);
}
EDIT:
We have to configure MessageConverter
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(new BufferedImageHttpMessageConverter());
}
Here I have Content Negotiator like this
#Bean
public ContentNegotiatingViewResolver contentViewResolver() throws Exception {
ContentNegotiatingViewResolver contentViewResolver = new ContentNegotiatingViewResolver();
ContentNegotiationManagerFactoryBean contentNegotiationManager = new ContentNegotiationManagerFactoryBean();
contentNegotiationManager.addMediaType("json", MediaType.APPLICATION_JSON);
contentViewResolver.setContentNegotiationManager(contentNegotiationManager.getObject());
contentViewResolver.setDefaultViews(Arrays.<View> asList(new MappingJackson2JsonView()));
return contentViewResolver;
}
I think the message inside your logs can clear your doubts. Have a close look at your logs and comment me again

Answer 2

I think the problem is that none of the registered message converters knows how to write a BufferedImage to the response in the format dictated by the accept header. Try registering your own message converter that knows how to write out a BufferedImage in the requested format.