RestEasy - Unable to find MessageBodyReader?

Question

I've written a simple RestEasy client proxy to perform an iTunes search. It looks like this:

@Path("/")
public interface AppleAppStoreLookupClient {

    /**
     * Attempts to lookup an apple app store item by its ID
     * 
     * @param id
     *            The item ID
     * @return The app details
     */
    @GET
    @Path("/lookup")
    @Produces(value = { "text/javascript" })
    public AppleAppDetailsResponse lookupByID(@QueryParam("id") String id);
}

My JSON model class is simple, as well. In fact, for the first call all I want is the "resultCount" value, just to make sure connectivity works.

@XmlRootElement
@XmlAccessorType(XmlAccessType.NONE)
public class AppleAppDetailsResponse implements Serializable {

    private static final long serialVersionUID = 8881587082097337598L;

    @XmlElement
    private int resultCount = -1;

   ...getters and setters...

}

However, when I run a simple test, I get the following Exception:

org.jboss.resteasy.client.ClientResponseFailure: Unable to find a MessageBodyReader of content-type text/javascript;charset="utf-8" and type class net.odyssi.mms.appstore.apple.AppleAppDetailsResponse
    at org.jboss.resteasy.client.core.BaseClientResponse.createResponseFailure(BaseClientResponse.java:523)
    at org.jboss.resteasy.client.core.BaseClientResponse.createResponseFailure(BaseClientResponse.java:514)
    at org.jboss.resteasy.client.core.BaseClientResponse.readFrom(BaseClientResponse.java:415)
    at org.jboss.resteasy.client.core.BaseClientResponse.getEntity(BaseClientResponse.java:377)
    at org.jboss.resteasy.client.core.BaseClientResponse.getEntity(BaseClientResponse.java:350)
    at org.jboss.resteasy.client.core.extractors.BodyEntityExtractor.extractEntity(BodyEntityExtractor.java:62)
    at org.jboss.resteasy.client.core.ClientInvoker.invoke(ClientInvoker.java:126)
    at org.jboss.resteasy.client.core.ClientProxy.invoke(ClientProxy.java:88)
    at $Proxy21.lookupByID(Unknown Source)
    at net.odyssi.mms.appstore.apple.test.AppleAppStoreLookupClientTest.testLookupByID(AppleAppStoreLookupClientTest.java:50)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)

I'm running RestEasy 2.3.6. Any idea what could be causing such an error?

Answer 1

Do you have a json provider on your classpath? If you are using maven, try adding this dependency:

 <dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-jettison-provider</artifactId>
    <version>2.3.6.Final</version>
</dependency>

http://docs.jboss.org/resteasy/docs/2.3.6.Final/userguide/html_single/#JAXB_+_JSON_provider

EDIT:

Normally, one would use the content type application/json and not text/javascript. I'm not sure why you are using text/javascript?

Anyways, if your endpoint returns only text/javascript, you can always modify the Content-Type-header in an interceptor:

ResteasyProviderFactory factory = new ResteasyProviderFactory();
RegisterBuiltin.register(factory);
factory.getClientExecutionInterceptorRegistry().register(
    new ClientExecutionInterceptor() {
        @Override
        public ClientResponse execute(ClientExecutionContext ctx) throws Exception {
            ClientResponse response = ctx.proceed();
            if("text/javascript".equals(response.getHeaders().getFirst(HttpHeaders.CONTENT_TYPE))){
                response.getHeaders().putSingle(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON);
            }
            return response;
        }
    });


ProxyFactory.create(Service.class, URI.create("http://url-to-your-sevice"), new ApacheHttpClient4Executor(), factory);