Custom input types

[rb090]

Hi 👋,

1st of all thanks a lot for this wonderful Kotlin GQL server which is compatible with KTor. I really like it.

I have few small question please. Please be patient with me I am really a beginner when it comes in writing GQL servers. So I really don't have that much experience.

When I have custom input types within my schema, used on the GQL operations like fe. within a Mutation, how to correctly retrieve them in the code?

Fe. I have this schema:

input UserObjectInput {
    userId: String!
    userName: String
    userBirthday: String
}

type ResultObject {
    attributeA: String!
    attributeB: String!
    attributeC: String
    productType: ProductType
}

enum ProductType {
    PRODUCT_A,
    PRODUCT_B,
    UNKNOWN
}

type Mutation {
    mutationWithUser(user: UserObjectInput!): ResultObject!
}

type Query {
    helloWorld: String
}

My Application class of my Ktor Server looks like this:

// Input object for GQL input object "UserObjectInput" from schema.graphql
data class MyUserInput(id: String, name: String?, birthday: String?)

// How to map ProductType schema enum to this Kotlin enum?
enum class ProductType { A_PRODUCT, B_PRODUCT, UNKNOWN }

data class MyResult(myAttr1: String, myAttr2: String, myAttr3: String?, type: ProductType)

fun main() {

    arianeServer {
        // Load schema.graphql file from resources folder
        schema = loadSchema("schema.graphql")
        //Indicate which HTTP port should be used (80 by default)
        port = 3000

        serverListener = object : ServerListener {
            override fun onStart(host: String, port: Int, path: String) {
                log.info("Server ready 🚀. Listening at http://localhost:$port$path")
            }
        }

        resolvers {
            Mutation {
                resolve("mutationWithUser") {
                    // The retrieved object by arguments is a LinkedHashMap?
                    // Do I manually need to create here `MyUserInput` oject from this `LinkedHashMap`
                    val user: LinkedHashMap<String, Any> = arguments["user"]

                    // Here the outcome of function `doSth()` would be `MyResult`
                    // How to map this to the GQL schema object `ResultObject`?
                    val result: MyResult = doSth()
                    result
                }
            }

        }
    }.launch()
}

Can you please tell me how the mapping "schema GQL objects" <-> Kotlin data classes needs to work with ariane-server? The mapping is my only issue here.

[mbiamont]

Hey,

Thanks for your comment, unfortunately, it's not possible yet. The project is still in early stage.

But I'm actively working on it. I'll keep you posted once it's possible.

[rb090]

Hi @mbiamont,

wow cool, thank you so much 🙌. I really like your code. It is so nice and clean. I would be really more than happy to support if I can. Please just let me know. At least testing is sth I can do quite good. Integrate it, try it out and all that stuff.

Tbh - before starting with Ariane, I did also a research about existing libraries. There are a couple of them, listed on the “official” community page of graphql. But none of them really convinced me. They are really heavy and I have a really small use case. So then I found your library and I was really amazed.

[mbiamont]

Hello @rb090

I just published a new version that should handle argument typing (v0.3.0). Also, I published a Gradle plugin.

The plugin will generate the types according to your graphQL schema, and the resolver functions. For instance, with this plugin, instead of writing

resolvers {
   Mutation {
      resolve<UserObjectInput>("mutationWithUser") {
         println("User ID = ${it.userId}")
      }
   }
}

You can write

resolvers {
   Mutation {
      mutationWithUser { (user) ->
         println("User ID = ${user.userId}")
      }
   }
}

More info here: https://arianegraphql.com/docs/codegen

Feel free to test it out and give me your feedback 🙏