Custom JSON serializer for MessageCodec

[Konstantinos Liakos]

I am trying to send a message over the event bus to a sockjs client. The message is a POJO, so I register a MessageCodec as in the example https://github.com/vert-x3/vertx-examples/blob/ea6e07945baa9abec6d6f4f98404c727cc8c342e/core-examples/src/main/java/io/vertx/example/core/eventbus/messagecodec/util/CustomMessageCodec.java

However I am replacing the JSON serialization code with a custom solution(using Gson).

JsonObject jsonToEncode = new JsonObject();
jsonToEncode.put("statusCode", myPojo.getStatusCode());
jsonToEncode.put("resultCode", myPojo.getResultCode());
jsonToEncode.put("summary", myPojo.getSummary());
String jsonToStr = jsonToEncode.encode();

Replaced with:

StringjsonStr = new GsonBuilder().create().toJson(myPojo);

This results to error:

SEVERE: Unhandled exception

java.lang.IllegalStateException: Illegal type in JsonObject: class MyPOJO

at io.vertx.core.json.Json.checkAndCopy(Json.java:125)

at io.vertx.core.json.JsonObject.put(JsonObject.java:645)

at io.vertx.ext.web.handler.sockjs.impl.EventBusBridgeImpl.deliverMessage(EventBusBridgeImpl.java:343)

at io.vertx.ext.web.handler.sockjs.impl.EventBusBridgeImpl.lambda$null$9(EventBusBridgeImpl.java:246)

at io.vertx.core.eventbus.impl.HandlerRegistration.deliver(HandlerRegistration.java:213)

at io.vertx.core.eventbus.impl.HandlerRegistration.handle(HandlerRegistration.java:192)

at io.vertx.core.eventbus.impl.EventBusImpl.lambda$deliverToHandler$3(EventBusImpl.java:503)

at io.vertx.core.impl.ContextImpl.lambda$wrapTask$3(ContextImpl.java:359)

at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:339)

at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:393)

at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:742)

at java.lang.Thread.run(Thread.java:745)

[Konstantinos Liakos]

Actually it seems that the MessageCodec is not invoked at all. Can't find out why.

[Paulo Lopes]

Did you register your codec?

vertx.eventBus().registerDefaultCodec(MyPOJO.class, new MyPOJOMessageCodec(engine));

[Konstantinos Liakos]

I did register the codec the way you mention it. But not passing anything to the constructor.  What exactly is this engine object you pass to the constructor?

[Konstantinos Liakos]

Did another test: copied the CustomMessage classes from the custom message coded example to the RealTime example https://github.com/vert-x3/vertx-examples/tree/master/web-examples/src/main/java/io/vertx/example/web/realtime

I register it the same way, and get the very same error. 

Failed to handleMessage 

java.lang.IllegalStateException: Illegal type in JsonObject: class io.vertx.example.web.realtime.util.CustomMessage

at io.vertx.core.json.Json.checkAndCopy(Json.java:125)

at io.vertx.core.json.JsonObject.put(JsonObject.java:645)

at io.vertx.ext.web.handler.sockjs.impl.EventBusBridgeImpl.deliverMessage(EventBusBridgeImpl.java:343)

at io.vertx.ext.web.handler.sockjs.impl.EventBusBridgeImpl.lambda$null$9(EventBusBridgeImpl.java:246)

at io.vertx.core.eventbus.impl.HandlerRegistration.deliver(HandlerRegistration.java:212)

at io.vertx.core.eventbus.impl.HandlerRegistration.handle(HandlerRegistration.java:191)

at io.vertx.core.eventbus.impl.EventBusImpl.lambda$deliverToHandler$3(EventBusImpl.java:503)

at io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:316)

at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)

at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:418)

at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:440)

at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:873)

at java.lang.Thread.run(Thread.java:745)

Unhandled exception 

java.lang.IllegalStateException: Illegal type in JsonObject: class io.vertx.example.web.realtime.util.CustomMessage

at io.vertx.core.json.Json.checkAndCopy(Json.java:125)

at io.vertx.core.json.JsonObject.put(JsonObject.java:645)

at io.vertx.ext.web.handler.sockjs.impl.EventBusBridgeImpl.deliverMessage(EventBusBridgeImpl.java:343)

at io.vertx.ext.web.handler.sockjs.impl.EventBusBridgeImpl.lambda$null$9(EventBusBridgeImpl.java:246)

at io.vertx.core.eventbus.impl.HandlerRegistration.deliver(HandlerRegistration.java:212)

at io.vertx.core.eventbus.impl.HandlerRegistration.handle(HandlerRegistration.java:191)

at io.vertx.core.eventbus.impl.EventBusImpl.lambda$deliverToHandler$3(EventBusImpl.java:503)

at io.vertx.core.impl.ContextImpl.lambda$wrapTask$2(ContextImpl.java:316)

at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:163)

at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:418)

at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:440)

at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:873)

at java.lang.Thread.run(Thread.java:745)

[Paulo Lopes]

Sorry that was a copy paste issue, there is no need to pass anything to the constructor.

Also is your MyPOJO a real class? I mean not an interface or a abstract class? because the match is done by the exact class type.

[Konstantinos Liakos]

Look my answer above, I did the same test by using the MessageCodec from the examples. And get the same failure. What am I missing here? Aren't codecs supposed to also work over via the sockjs bridge?

[Paulo Lopes]

I can't see what you're doing wrong since you refer first to MyPOJO but there is no MyPOJO code and the error you showed is because there is an non JSON valid type inside the JsonObject. Could you share a reproducer?

[Konstantinos Liakos]

Yes I have mixed a couple of examples here...

So you do say that custom codecs do work over the SockJS bridge? Is this designed to work?

If yes, I will set up a github repo with an example reproducing the case.

[Konstantinos Liakos]

After reading the code, I get the impression that SockJS messages over the event bus bridge are always implicitly JsonObject.

https://github.com/vert-x3/vertx-web/blob/09a2463262b46b1826c088624f549b3cbb6f4f01/vertx-web/src/main/java/io/vertx/ext/web/handler/sockjs/impl/EventBusBridgeImpl.java#L342

On Wednesday, 2 November 2016 16:48:48 UTC+2, Paulo Lopes wrote:

[Konstantinos Liakos]

Can anyone confirm if the custom codecs are supposed to work over the SockJS event bridge?

[Konstantinos Liakos]

Here is the full example for anyone interested looking into this: https://github.com/kliakos/vertx-sockjs-example