Increase integration potential of msgpack-jackson

[extbe]

Hello MessagePack Team!

I use MessagePack Jackson integration in my project and have an issue integrating it with other libraries that rely on Jackson API.

The MessagePackFactory overrides only a part of JsonFactory#createParser methods which limits the integration potential because not all libraries create parser from InputStream or byte[].

What do you think about expanding the list of overriden createParser methods and thus increasing the integration potential?

[komamitsu]

@extbe Which createParser() do you actually need?

[extbe]

The one that accepts Reader as a parameter

public JsonParser createParser(Reader r) throws IOException, JsonParseException {
    //...
}

https://github.com/FasterXML/jackson-core/blob/0d2b0f39200d466f49f1abb06d9027053d41483d/src/main/java/com/fasterxml/jackson/core/JsonFactory.java#L1242

[komamitsu]

@extbe Reader is for char stream while MessagePack is a binary format. So, I don't think Reader works well with MessagePack.

[extbe]

@komamitsu This is what I'm trying to solve.

I'm trying to integrate Feign, Jackson and MessagePack. MessagePack and Feign both provide Jackson integration. Feign relies on createParser(Reader r) method which seems logical because JSON is a text format. MessagePack is a binary format, and now I also think that it is logical to not support that method.

Feign is a good declarative wrapper for HTTP clients and MessagePack is a good binary format, so I would like to make them compatible.

Initially I was thinking that the correct way is to support that method in msgpack-jackson as it works behind the Jackson API, but now I'm not sure that it will be the right decision. It seems like the integration should be placed in a separate library so that none of the existing APIs will be affected.

Since msgpack-jackson works behind the Jackson API, but implements only a part of the API, would you agree putting the integration library into msgpack-java? The library will integrate msgpack-jackson and Feign taking into account the implementation details of msgpack-jackson.

[komamitsu]

@extbe

Feign relies on createParser(Reader r) method

I guess it's true only when using the bundled JacksonEncoder and JacksonDecoder. I'm not familiar with Feign, but I'm wondering if you can create own MessagePackEncoder and MessagePackDecoder with Jackson that handles only binary data.

I recommend creating a separate integration library like https://github.com/komamitsu/retrofit-converter-msgpack, as I think msgpack-java should be as simple as possible.