Hi I m trying to add a conversion from Set lt gt to a GraphQ

Question

Hi I m trying to add a conversion from Set lt gt to a GraphQLList I know it is not inherently supported in GQL but the backing data is read only and has already been implemented using sets For simplicity lets say we have ```data class TestClass val content Set lt String gt ``` to remedy this I ve added a Hook with the following SchemaGeneratorHooks willGenerateGrpahQLType method ``` ExperimentalStdlibApi override fun willGenerateGraphQLType type KType GraphQLType = when type isSubtypeOf typeOf lt Set lt gt gt gt type arguments first type let kType gt val typeRef = kType classifier as KClass lt gt GraphQLList list GraphQLTypeReference typeRef typeRef simpleName else gt null ``` this works when creating a query that returns TestClass or List lt TestClass gt However when creating a Query that returns a Set lt TestClass gt it fails as the TestClass reference has not yet been created From what I could gather this method should just create the reference to `TestClass class simpleName` and the generator should generate the class in due time which should lead to Set lt TestClass gt resolving as a GQLList lt TestClass gt in the playground or am I missing something

Anders Kirkeby · Answer

I ve also had a look at and but from what I can see the `SchemaGenerator generateAdditionalTypes` method is no longer open as indicated by the comments and PR

Dariusz Kuc · Answer

gql reference is a pointer to actual gql implementation

Dariusz Kuc · Answer

so if you create a query that returns that set gt does anything in your schema actually reference the actual `TestClass`

Dariusz Kuc · Answer

i e is your reference pointing to non existent type

Anders Kirkeby · Answer

Ye scratch those thinking face Short answer ye I guess I am referencing a non existent type as I m hooking into its creation process and interrupting its creation by creating the List ref instead So how could I do that in a bottom up approach rather than a top down way

Anders Kirkeby · Answer

I guess this is also part of what I m curious about from the GraphQLTypeReference ``` A special type to allow a object interface types to reference itself It s replaced with the real type object when the schema is built ``` I initially assumed that the GraphQLTypeReference typeRef typeRef simpleName would just defer it s creation time up the last possible moment ie when the subclass would be part of the schema

Anders Kirkeby · Answer

After scratching my head a bit more it is exactly the same as one of the refs i added above I m not quite sure how to use the proposed fix either as the example doesn t work with the methods provided ``` override fun generateAdditionalTypes types Set lt KType gt Set lt GraphQLType gt val newTypes = types toMutableSet add MyNewType class createType return super generateAdditionalTypes newTypes ``` should work but the `SchemaGenerator generateAdditionalTypes` takes no args ``` Generate the GraphQL type for all the `additionalTypes` If you need to provide more custom additional types that were not picked up from reflection of the schema objects you can provide more types to be added through generateSchema This function loops because while generating the additionalTypes it is possible to create more additional types that need to be processed protected fun generateAdditionalTypes Set lt GraphQLType gt val graphqlTypes = mutableSetOf lt GraphQLType gt while this additionalTypes isNotEmpty val currentlyProcessedTypes = LinkedHashSet this additionalTypes this additionalTypes clear graphqlTypes addAll currentlyProcessedTypes map GraphQLTypeUtil unwrapNonNull generateGraphQLType this it kType it inputType return graphqlTypes ``` I m sure there s something simple that I m missing but I cannot for the life of me find a way to make the resolver just override Collections with List which seems like the simplest thing stuck out tongue

Dariusz Kuc · Answer

you can pass `additionalTypes` `additionalInputTypes` as arguments to schema generation process

Dariusz Kuc · Answer

see <https github com ExpediaGroup graphql kotlin blob master graphql kotlin schema generator src main kotlin com expediagroup graphql generator SchemaGenerator kt L74>

Dariusz Kuc · Answer

looks like the docs are outdated

Anders Kirkeby · Answer

That would still require me to add the TestClass manually though right thinking face Cause I won t have access to the subtypes of the query in the scope of the generateSchema method

Dariusz Kuc · Answer

Yep Add the test class to the list of additional types and then use your hook to convert set to list of references

Dariusz Kuc · Answer

that would be the simplest approach alternatively you could build underlying type in the hook instead of just a reference

Anders Kirkeby · Answer

Right that makes sense I guess what I was hoping for was to just bypass the Set lt gt part and replace it with List lt gt and lett the default schemagenerator resolve the T part But that works Maybe an model integration layer would be a prettier way of exposing the underlying data thinking face Thanks < Dariusz Kuc>

Dariusz Kuc · Answer

Since you are serializing it to a list anyway

Dariusz Kuc · Answer

You could also just do toList on it and just expose a list

Anders Kirkeby · Answer

Ye for my example there that would be the definite answer and way cleaner Was more if say the TestClass contained a set of a different class which whould require us to remake the TestClass gt TestClassQL containing a list of the same data

Anders Kirkeby · Answer

eg ```data class TestClass val content Set lt OtherTestClass gt ``` which would require ```data class TestClassQL val content List lt OtherTestClass gt ```

Dariusz Kuc · Answer

You could still convert the raw class with set to a gql model with list but that is also extra logic

Anders Kirkeby · Answer

Indeed It would need to be resolved at one place or another so I guess there s no magic way of doing it slightly smiling face

Dariusz Kuc · Answer

Pretty much

Dariusz Kuc · Answer

Since its going to be serialized to json array you will loose any set properties anyway so I d just expose it as a list to keep it consistent

Anders Kirkeby · Answer

Yep My initial thought was that since this was read only converting it from set gt list would stil retain the collection properties I agree that with mutations this would be a different story as you would potentially loose information on the way back in so rather than have a `listOf unique ` we would use setOf instead and just expose it as a list of unique values

Dariusz Kuc · Answer

if it needs to be unique i d keep it internally as set and do all the processing on it as set but expose it as a read only list

Anders Kirkeby · Answer

Yep I agree I was initially hoping to be able to hook into the schema generator to automagically convert from set gt list on the way out simply to save the need of having multiple models representing the underlying data

Anders Kirkeby · Answer

But it might be cleaner overall to just have it expose json friendly models