info for https://github.com/dropwizard/dropwizard/issues/625

PostWithData

##### REQUEST #####
curl -v -X POST -d "{}" http://localhost:8080/v1/session?preset=min --header "Content-Type:application/json"
* Hostname was NOT found in DNS cache
*   Trying ::1...
* Connected to localhost (::1) port 8080 (#0)
> POST /v1/session?preset=min HTTP/1.1
> User-Agent: curl/7.37.0
> Host: localhost:8080
> Accept: */*
> Content-Type:application/json
> Content-Length: 2
>
* upload completely sent off: 2 out of 2 bytes
< HTTP/1.1 200 OK
< Date: Tue, 24 Jun 2014 15:01:15 GMT
< Content-Type: application/json; charset=utf-8
< Transfer-Encoding: chunked
<
{"id":"8m7ncd8z1sckqu1hm7dgl9atzoj0td4vv","authenticated":false,"memberId":4675863136}* Connection #0 to host localhost left intact

#### STACKTRACE #####
None in this case as at JacksonMessageBodyProvider.validate(Annotation[], Object) line: 69 the "value" parameter now has an instance of "SessionStandard" (see ResourceMethod) created with the default constructor.

PostWithoutData

##### REQUEST #####
curl -v -X POST -d "" http://localhost:8080/v1/session?preset=min --header "Content-Type:application/json"
* Hostname was NOT found in DNS cache
*   Trying ::1...
* Connected to localhost (::1) port 8080 (#0)
> POST /v1/session?preset=min HTTP/1.1
> User-Agent: curl/7.37.0
> Host: localhost:8080
> Accept: */*
> Content-Type:application/json
> Content-Length: 0
>
< HTTP/1.1 422
< Date: Tue, 24 Jun 2014 14:55:45 GMT
< Content-Type: application/json; charset=utf-8
< Transfer-Encoding: chunked
* HTTP error before end of send, stop sending
<
{"errors":[]}* Closing connection 0

#### STACKTRACE ##### (exception does not get thrown because it's catched somewhere else but is of type ConstraintViolationException and the message is "The request entity was empty"
JacksonMessageBodyProvider.validate(Annotation[], Object) line: 69	
JacksonMessageBodyProvider.readFrom(Class<Object>, Type, Annotation[], MediaType, MultivaluedMap<String,String>, InputStream) line: 60	
ContainerRequest.getEntity(Class<T>, Type, Annotation[]) line: 490	
EntityParamDispatchProvider$EntityInjectable.getValue(HttpContext) line: 123	
InjectableValuesProvider.getInjectableValues(HttpContext) line: 86	
AbstractResourceMethodDispatchProvider$TypeOutInvoker(AbstractResourceMethodDispatchProvider$EntityParamInInvoker).getParams(HttpContext) line: 153	
AbstractResourceMethodDispatchProvider$TypeOutInvoker._dispatch(Object, HttpContext) line: 183	
AbstractResourceMethodDispatchProvider$TypeOutInvoker(ResourceJavaMethodDispatcher).dispatch(Object, HttpContext) line: 75	
InstrumentedResourceMethodDispatchProvider$MeteredRequestDispatcher.dispatch(Object, HttpContext) line: 49	
OptionalResourceMethodDispatchAdapter$OptionalRequestDispatcher.dispatch(Object, HttpContext) line: 37	
HttpMethodRule.accept(CharSequence, Object, UriRuleContext) line: 302	
ResourceObjectRule.accept(CharSequence, Object, UriRuleContext) line: 100	
RightHandPathRule.accept(CharSequence, Object, UriRuleContext) line: 147	
RootResourceClassesRule.accept(CharSequence, Object, UriRuleContext) line: 84	
WebApplicationImpl._handleRequest(WebApplicationContext, ContainerRequest) line: 1542	
WebApplicationImpl._handleRequest(WebApplicationContext, ContainerRequest, ContainerResponse) line: 1473	
WebApplicationImpl.handleRequest(ContainerRequest, ContainerResponse) line: 1419	
WebApplicationImpl.handleRequest(ContainerRequest, ContainerResponseWriter) line: 1409	
ServletContainer$InternalWebComponent(WebComponent).service(URI, URI, HttpServletRequest, HttpServletResponse) line: 409	
ServletContainer.service(URI, URI, HttpServletRequest, HttpServletResponse) line: 540	
ServletContainer.service(HttpServletRequest, HttpServletResponse) line: 715	
ServletContainer(HttpServlet).service(ServletRequest, ServletResponse) line: 848	
NonblockingServletHolder.handle(Request, ServletRequest, ServletResponse) line: 49	
ServletHandler$CachedChain.doFilter(ServletRequest, ServletResponse) line: 1515	
BiDiGzipFilter(UserAgentFilter).doFilter(ServletRequest, ServletResponse, FilterChain) line: 83	
BiDiGzipFilter(GzipFilter).doFilter(ServletRequest, ServletResponse, FilterChain) line: 295	
BiDiGzipFilter.doFilter(ServletRequest, ServletResponse, FilterChain) line: 127	
ServletHandler$CachedChain.doFilter(ServletRequest, ServletResponse) line: 1486	
ThreadNameFilter.doFilter(ServletRequest, ServletResponse, FilterChain) line: 29	
ServletHandler$CachedChain.doFilter(ServletRequest, ServletResponse) line: 1486	
AllowedMethodsFilter.handle(HttpServletRequest, HttpServletResponse, FilterChain) line: 44	
AllowedMethodsFilter.doFilter(ServletRequest, ServletResponse, FilterChain) line: 39	
ServletHandler$CachedChain.doFilter(ServletRequest, ServletResponse) line: 1486	
ServletHandler.doHandle(String, Request, HttpServletRequest, HttpServletResponse) line: 519	
MutableServletContextHandler(ContextHandler).doHandle(String, Request, HttpServletRequest, HttpServletResponse) line: 1097	
ServletHandler.doScope(String, Request, HttpServletRequest, HttpServletResponse) line: 448	
MutableServletContextHandler(ContextHandler).doScope(String, Request, HttpServletRequest, HttpServletResponse) line: 1031	
MutableServletContextHandler(ScopedHandler).handle(String, Request, HttpServletRequest, HttpServletResponse) line: 136	
InstrumentedHandler(HandlerWrapper).handle(String, Request, HttpServletRequest, HttpServletResponse) line: 97	
InstrumentedHandler.handle(String, Request, HttpServletRequest, HttpServletResponse) line: 175	
RoutingHandler.handle(String, Request, HttpServletRequest, HttpServletResponse) line: 51	
RequestLogHandler(HandlerWrapper).handle(String, Request, HttpServletRequest, HttpServletResponse) line: 97	
RequestLogHandler.handle(String, Request, HttpServletRequest, HttpServletResponse) line: 92	
StatisticsHandler(HandlerWrapper).handle(String, Request, HttpServletRequest, HttpServletResponse) line: 97	
StatisticsHandler.handle(String, Request, HttpServletRequest, HttpServletResponse) line: 162	
Server(HandlerWrapper).handle(String, Request, HttpServletRequest, HttpServletResponse) line: 97	
Server.handle(HttpChannel<?>) line: 446	
HttpConnection$HttpChannelOverHttp(HttpChannel<T>).handle() line: 271	
HttpConnection.onFillable() line: 246	
AbstractConnection$ReadCallback.run() line: 358	
InstrumentedQueuedThreadPool(QueuedThreadPool).runJob(Runnable) line: 601	
QueuedThreadPool$3.run() line: 532	
Thread.run() line: not available	

ResourceMethod

 @POST
  @Metered
  @ApiOperation(value = "Create a new session",
      response = Session.class)
  public Session createSession(
      @ApiParam(value = "Session Details", required = false) SessionStandard session ,
      @ApiParam(allowableValues = ApiFilterConstants.PRESET_OBJECT_TYPE_FILTER_MINIMAL_OBJECT + "," +
          ApiFilterConstants.PRESET_OBJECT_TYPE_FILTER_STANDARD_OBJECT)
      @DefaultValue(ApiFilterConstants.PRESET_OBJECT_TYPE_FILTER_MINIMAL_OBJECT)
      @QueryParam(value = ApiFilterConstants.PRESET_OBJECT_TYPE_FILTER_NAME) String presetFieldType )
      throws CommonException {/*...*/}
  }

Workaround

package x;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.ws.rs.core.MediaType;
import javax.ws.rs.ext.Provider;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.sun.jersey.spi.container.ContainerRequest;
import com.sun.jersey.spi.container.ContainerRequestFilter;

@Provider
public class TransformNullPostAndPutBodiesToEmptyJsonObjectFilter implements ContainerRequestFilter {

  private Logger logger = LoggerFactory.getLogger(TransformNullPostAndPutBodiesToEmptyJsonObjectFilter.class);
  private final String EMPTY_JSON_OBJECT = "{}";

  @Override
  public ContainerRequest filter( ContainerRequest request ) {
    MediaType mediaType = request.getMediaType();
    String method = request.getMethod();
    boolean isMethodPostOrPut = ("POST".equalsIgnoreCase(method) || "PUT".equalsIgnoreCase(method));
    boolean isJSON = (MediaType.APPLICATION_JSON_TYPE.equals(mediaType));
    try {
      boolean isEntityEmpty = (request.getEntityInputStream().available() == 0);

      if (isMethodPostOrPut && isJSON && isEntityEmpty) {
        logger.info("Got an empty entity body with method={} and mediaType={}. Will inject {} into the request", method, mediaType,
            EMPTY_JSON_OBJECT);
        //close the old stream (we're not taking any chances)
        if (request.getEntityInputStream() != null) {
          request.getEntityInputStream().close();
        }
        //set the new one
        InputStream is = new ByteArrayInputStream(EMPTY_JSON_OBJECT.getBytes());
        request.setEntityInputStream(is);
        logger.info("Successfully injected {} into the request", EMPTY_JSON_OBJECT);
      }
    } catch (IOException e) {
      logger.error("Caught exception while trying to inject an empty JSON object into the request: {}\n.", e.getMessage());
      logger.error("Will proceed with method={},mediaType={} and empty entity body. This may cause some problems in a second", method,
          mediaType);
    }
    return request;
  }
}