Adding extensions to GraphQL response

SmallRye GraphQL allows the user to add their own extensions inside the GraphQL response which is received from the server. The extensions are stored next to the data field in the GraphQL response.

{
  "data": {
    "shirt": {
      "size": "L"
    }
  },
  "extensions": {
    "country": "Germany",
    "pi": 3.1415926535
  }
}

To add extensions, you need to @Inject an instance of SmallRyeContext in your @GraphQLApi annotated class. After that, you can add your own extensions via the method addExtensions with its input parameters: key : String as an identification of the added extension. And value: Object as a value of the extension. Value can be any given object that can be converted into JsonValue.

As an example, this class below contains the query getShirt and during the http request, the query adds these extensions: {"country": "Germany", "pi": 3.1415926535}. These extensions will be sent back via response in the extensions field.

import jakarta.inject.Inject;

@GraphQLApi
public class ShirtResources {
    @Inject
    SmallRyeContext smallRyeContext;

    @Query
    public Shirt getShirt() {
        smallRyeContext.addExtensions("country", "Germany");
        smallRyeContext.addExtensions("pi", 3.1415926535);
        //...
    }
}

[NOTE] You can also use the method setAddedExtensions(Map<String, Object> addedExtensions) to set all the extensions with map instance.