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I know this belongs in graphql-java-kickstart, since I am a user of it, but trying here as well since it is related to graphql-java as well. Is there a way to override the wiring/type resolution for a single type but keep the rest? I have a GraphQL interface Fruit which has subtypes Apple and Banana. There exists a corresponding java interface Fruit and java classes Apple and Banana . How do I introduce a new class only on the java side, lets say called Orange, which on the java side implements Fruit, but I want it to resolve to Banana on the GraphQL side (so I do not have to introduce another GraphQL type in the schema). I have tried using TypeResolvers for this. (See graphql-java-kickstart/graphql-java-tools#718). My problem stems from me wanting to extend an existing GraphQL interface with a new subtype, but this breaks backward compatibility for clients. I am considering other techniques:
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Replies: 2 comments 3 replies
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From graphql-java's perspective, each individual interface/union types has its own type resolver. So even if Kickstart isn't letting you customize it per-type, you can always transform the result by changing the |
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Thanks, I got the type resolver part working, but how do I override the data fetcher for this type? Can this also be done through the registry? |
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Assuming that kickstarts type resolves work like the base graphql java ones you would just do this in Java code I dont know how kickstart allows you to plugin in |
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Yes, that works. With graphql-java-tools I used the following: val executableSchema = schemaParser.makeExecutableSchema()
val oldFruitTypeResolver =
executableSchema.codeRegistry.getTypeResolver(GraphQLInterfaceType.newInterface().name("Fruit").build())
val fruitTypeResolver = TypeResolver { env ->
when {
env.getObject<Any>() is Orange -> env.schema.getObjectType("Banana")
else -> oldFruitTypeResolver.getType(env)
}
}
val schemaObjects = schemaParser.parseSchemaObjects()
return GraphQLSchema.newSchema()
.description(schemaObjects.description)
.query(schemaObjects.query)
.mutation(schemaObjects.mutation)
.subscription(schemaObjects.subscription)
.additionalTypes(schemaObjects.dictionary)
.additionalDirectives(schemaObjects.directives)
.codeRegistry(
schemaObjects.codeRegistryBuilder
.typeResolver("Fruit", fruitTypeResolver)
.build()
)
.build()But, now I need a way to override the data fetchers as well, preferably only for Fruit and the subtypes of Fruit |
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I was able to override the data fetchers using the codeRegistry. The trick was to use the existing schema, and traverse it using a visitor and record all the FieldCoordinates that needed and overridden data fetcher. |
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From graphql-java's perspective, each individual interface/union types has its own type resolver. So even if Kickstart isn't letting you customize it per-type, you can always transform the result by changing the
GraphQLCodeRegistryand overriding the specific type resolver.