Content type blank is not supported - spring

Question

I want to handle the POST request when there is empty content-type.
When I add consumes = MediaType.APPLICATION_JSON_VALUE
and make a request in postman with Content-type blank I get the following error
{
"timestamp": 1581594986909,
"status": 415,
"error": "Unsupported Media Type",
"message": "Content type '' not supported",
"path": "/test"
}
Here is the code
#PostMapping(produces = MediaType.APPLICATION_JSON_VALUE, consumes = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity create(#RequestBody TestRequest testRequest) throws TestException {
LOG.debug("Starting...");
//code
return createtest(testRequest);
}
when i remove consumes = MediaType.APPLICATION_JSON_VALUE
and make a request with content-type = blank
i get the following error
{
"timestamp": 1581595348209,
"status": 415,
"error": "Unsupported Media Type",
"message": "Content type 'application/octet-stream' not supported",
"path": "/test"
}
Here is the code
#PostMapping(produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity create(#RequestBody TestRequest testRequest) throws TestException {
LOG.debug("Starting...");
//code
return createtest(testRequest);
}
Here is the POstMan request
I want to handle this scenario and assume as if content-Type= application/json is sent

Answer 1

To handle empty Content-Type as if application/json, you need to configure MappingJackson2HttpMessageConverter to support application/octet-stream and controller's method (i.e. your create method) consumes both application/octet-stream and application/json.
For example:
[CONFIGURATION]
#Configuration(proxyBeanMethods = false)
public class MyConfigurer {
#Bean
public HttpMessageConverters customConverters() {
Jackson2ObjectMapperBuilder builder = new Jackson2ObjectMapperBuilder();
MappingJackson2HttpMessageConverter converter = new MappingJackson2HttpMessageConverter(builder.build());
List<MediaType> supportedMediaTypes = new ArrayList<>();
supportedMediaTypes.addAll(converter.getSupportedMediaTypes());
supportedMediaTypes.add(MediaType.APPLICATION_OCTET_STREAM);
converter.setSupportedMediaTypes(supportedMediaTypes);
return new HttpMessageConverters(converter);
}
}
[CONTROLLER'S METHOD]
#PostMapping(produces = MediaType.APPLICATION_JSON_VALUE, consumes = {
MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_OCTET_STREAM_VALUE })
public ResponseEntity create(#RequestBody TestRequest testRequest) throws TestException {
LOG.debug("Starting...");
//code
return createtest(testRequest);
}
Spring seems to assume that Content-Type is application/octet-stream when Content-Type is empty and by default configuration MappingJackson2HttpMessageConverter supports application/json and application/*+json only. Therefore you need to modify your configuration and controller's method like above.
Following references are helpful for you:
Javadoc of MappingJackson2HttpMessageConverter
Spring boot documents

Answer 2

I finally configured it and it is working. Here is the correct configuration for MappingJackson2HttpMessageConverter
#Configuration(proxyBeanMethods = false)
public class WebMvcConfig implements WebMvcConfigurer {
#Override
public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
converters.add(jacksonMessageConverter());
WebMvcConfigurer.super.configureMessageConverters(converters);
}
#Bean
public MappingJackson2HttpMessageConverter jacksonMessageConverter() {
MappingJackson2HttpMessageConverter messageConverter = new MappingJackson2HttpMessageConverter();
List<MediaType> supportedMediaTypes=new ArrayList<>();
supportedMediaTypes.addAll(messageConverter.getSupportedMediaTypes());
messageConverter.setSupportedMediaTypes(supportedMediaTypes);
supportedMediaTypes.add(MediaType.APPLICATION_OCTET_STREAM);
messageConverter.setSupportedMediaTypes(supportedMediaTypes);
messageConverter.setPrettyPrint(true);
return messageConverter;
}
Aso add the APPLICATION_OCTET_STREAM_VALUE } in the controller method you want to support the octet-stream.
consumes = { MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_OCTET_STREAM_VALUE
}