Support for jboss/wildfly/resteasy

[ovkhasch]

We were trying to run OCI SDK client from an app deployed to wildfly 10.1.0, but were having issues with a default client configuration. I suggest to create a specialized resteasy client configurator, similar to ApacheConfigurator. We had to resolve the following two issues:

1. The request body is being passed as a java.lang.String object to a json provider. This results in the following error:

Caused by: javax.ws.rs.ProcessingException: RESTEASY004655: Unable to invoke request
	at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.invoke(ApacheHttpClient4Engine.java:287)
	at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.invoke(ClientInvocation.java:436)
	at org.jboss.resteasy.client.jaxrs.internal.ClientInvocationBuilder.post(ClientInvocationBuilder.java:195)
	at com.oracle.bmc.http.internal.ForwardingInvocationBuilder.post(ForwardingInvocationBuilder.java:154)
	at com.oracle.bmc.http.internal.RestClient.post(RestClient.java:144)
	... 9 more
Caused by: javax.ws.rs.ProcessingException: RESTEASY003215: could not find writer for content-type application/json type: java.lang.String
	at org.jboss.resteasy.core.interception.ClientWriterInterceptorContext.throwWriterNotFoundException(ClientWriterInterceptorContext.java:40)
	at org.jboss.resteasy.core.interception.AbstractWriterInterceptorContext.getWriter(AbstractWriterInterceptorContext.java:140)
	at org.jboss.resteasy.core.interception.AbstractWriterInterceptorContext.proceed(AbstractWriterInterceptorContext.java:119)
	at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.writeRequestBody(ClientInvocation.java:370)
	at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.writeRequestBodyToOutputStream(ApacheHttpClient4Engine.java:558)
	at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.buildEntity(ApacheHttpClient4Engine.java:524)
	at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.loadHttpMethod(ApacheHttpClient4Engine.java:423)
	at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.invoke(ApacheHttpClient4Engine.java:281)
	... 13 more

the workaround would be to use the following custom provider:

@Provider
@Produces(MediaType.APPLICATION_JSON)
public class RawStringJsonProvider implements MessageBodyWriter<String> {
    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType){
        if (String.class.equals(type) && mediaType.equals(MediaType.APPLICATION_JSON_TYPE)) {
            return true;
        }

        return false;
    }

    @Override
    public long getSize(String s, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return 0;
    }

    @Override
    public void writeTo(String s, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType, MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream) throws IOException, WebApplicationException {
        Writer writer = new PrintWriter(entityStream);
        writer.write(s);
        writer.flush();
        writer.close();
    }
}

2. A content-length header is being added by AuthnClientFilter, which results in:

Caused by: javax.ws.rs.ProcessingException: RESTEASY004655: Unable to invoke request
	at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.invoke(ApacheHttpClient4Engine.java:287)
	at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.invoke(ClientInvocation.java:436)
	at org.jboss.resteasy.client.jaxrs.internal.ClientInvocationBuilder.post(ClientInvocationBuilder.java:195)
	at com.oracle.bmc.http.internal.ForwardingInvocationBuilder.post(ForwardingInvocationBuilder.java:154)
	at com.oracle.bmc.http.internal.RestClient.post(RestClient.java:144)
	... 75 more
Caused by: org.apache.http.client.ClientProtocolException
	at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:886)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:82)
	at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:55)
	at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.invoke(ApacheHttpClient4Engine.java:283)
	... 79 more
Caused by: org.apache.http.ProtocolException: Content-Length header already present
	at org.apache.http.protocol.RequestContent.process(RequestContent.java:96)
	at org.apache.http.protocol.ImmutableHttpProcessor.process(ImmutableHttpProcessor.java:132)
	at org.apache.http.protocol.HttpRequestExecutor.preProcess(HttpRequestExecutor.java:166)
	at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:485)
	at org.apache.http.impl.client.AbstractHttpClient.doExecute(AbstractHttpClient.java:882)
	... 82 more

This can be fixed by either adding another filter which simply removes this header or using ApacheConfigurator like this:

VirtualNetworkClient vcnClient = VirtualNetworkClient.builder().clientConfigurator(new ApacheConfigurator()).build(provider);

[jodoglevy]

Good timing - I think we're actually already working on exactly this :)

Hopefully should have something to report soon.

[dayongfu]

Now Java SDK should support resteasy. Please check https://github.com/oracle/oci-java-sdk/blob/master/CHANGELOG.md for the examples. Please let us know if you have any problem to use it.

[jodoglevy]

Please see https://docs.cloud.oracle.com/iaas/Content/API/SDKDocs/javasdkconfig.htm#UsingYourOwnJAXRSImplementation for the docs about this