Add support for `application/json-patch+json` media type

[tvallin]

Environment Details

• Helidon Version: 3.2.7
• Helidon SE and Helidon MP
• JDK version: 17
• OS: n/a
• Docker version (if applicable):

---

Problem Description

Add support for application/json-patch+json media type.

Steps to reproduce

n/a

[romain-grecourt]

This is do-able with JSON-P.

@Path("/patch")
public class JsonPatchResource {

    private static final JsonProvider JSON_PROVIDER = JsonProvider.provider();

    private JsonObject jsonObject = JsonValue.EMPTY_JSON_OBJECT;

    @GET
    public JsonObject get() {
        return jsonObject;
    }

    @PUT
    public void put(JsonObject jsonObject) {
        this.jsonObject = jsonObject;
    }

    @Consumes("application/json-patch+json")
    @POST
    public void patch(JsonArray operations) {
        JsonPatch patch = JSON_PROVIDER.createPatch(operations);
        this.jsonObject = patch.apply(jsonObject);
    }
}

# verify the empty initial state
curl http://localhost:8080/patch
{}

# set the object
curl -X PUT -H "Content-Type: application/json" http://localhost:8080/patch -d '{"foo": "bar"}'

# verify the object
curl http://localhost:8080/patch
{"foo":"bar"}

# patch the object
curl -X POST -H "Content-Type: application/json-patch+json" http://localhost:8080/patch -d '[ {"op":"replace","path":"/foo","value": "123"} ]'

# verify the result
curl http://localhost:8080/patch
{"foo":"123"}

We should double-check if this also works with Helidon SE. If this works, we should create examples for both.