Spring Boot (RestController) - support for application/octet-stream using InputStream

WebConfig.groovy

/**
 * Adds support for application/octet-stream through a RestController using streams.
 */
@Configuration
class WebConfig extends WebMvcConfigurationSupport {
    @Override
    protected void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        converters.add(new AbstractHttpMessageConverter<InputStream>(MediaType.APPLICATION_OCTET_STREAM) {
            protected boolean supports(Class<?> clazz) {
                return InputStream.isAssignableFrom(clazz)
            }

            protected InputStream readInternal(Class<? extends InputStream> clazz, HttpInputMessage inputMessage) throws IOException, HttpMessageNotReadableException {
                return inputMessage.body
            }

            protected void writeInternal(InputStream inputStream, HttpOutputMessage outputMessage) throws IOException, HttpMessageNotWritableException {
                IOUtils.copy(inputStream, outputMessage.body)
            }
        })

        super.configureMessageConverters(converters);
    }
}

I was using RestController and wanted to have certain endpoints that accept binary file uploads with Content-Type: application/octet-stream, and certain other endpoints that deliver downloads the same way. I did not want to use multipart/form-data.

As far as I could tell, Spring does not support this out of the box, but it's easy enough to add as shown in this gist.

Once the message converter is registered, here's an example of it in use:

@RestController
class RepositoryController {

    @ApiOperation(value = "Store an asset")
    @RequestMapping(value = "/api/repository/assets/{id}", method = RequestMethod.POST, consumes = "application/octet-stream")
    @ResponseStatus(HttpStatus.CREATED)
    void storeAsset(@PathVariable String id, RequestEntity<InputStream> entity) {
        repositoryService.saveAsset(id, entity.getBody())
    }
}

Perfect - I was not aware that spring is not able for such a simple thing... thx a lot!

Lovely trick

Thanks. Very helpful...!!!

Thanks for this, really useful. Note that I made a Java version from the groovy one.