Directive @default

Let define a GraphQL schema:

type Query {
    films: Film!
}

type Film {
    id: ID!
    title: String!
}

This schema allows us to write a query using the generated DSL that looks like this:

val context: ExampleContext = exampleContextOf(createMyAdapter())
val response = context.query {
    films {
        id()
        title()
    }
}

response.films.forEach { film ->
    println("Film ${film.id} ${film.title}")
}

Imagine that the id field is present in almost all of our queries in the application code. In order not to write boilerplate code, we can ask Kobby to generate a DSL in such a way that this field is automatically added to the query. This can be done using a GraphQL directive @default. Let's modify our schema:

directive @default on FIELD_DEFINITION

type Query {
    films: [Film!]!
}

type Film {
    id: ID! @default
    title: String!
}

Now we can write our query like this:

val context: ExampleContext = exampleContextOf(createMyAdapter())
val response = context.query {
    films {
        title()
    }
}

response.films.forEach { film ->
    println("Film ${film.id} ${film.title}")
}

The generated DSL will automatically add the id field to the projection of the Film query. If you need to exclude the id field from the query, use the __withoutId() function generated by Kobby:

val context: ExampleContext = exampleContextOf(createMyAdapter())
val response = context.query {
    films {
        __withoutId()
        title()
    }
}

response.films.forEach { film ->
    println("Film ${film.title}")
}

To exclude from the query all fields of type Film, marked with the directive @default, use the __minimize() function:

val context: ExampleContext = exampleContextOf(createMyAdapter())
val response = context.query {
    films {
        __minimize()
        title()
    }
}

response.films.forEach { film ->
    println("Film ${film.title}")
}

The __minimize() function is automatically generated for all types defined in the schema, regardless of whether those types have fields marked with @default directive or not.

Restrictions

• The @default directive can only be applied to a field with no arguments.
• The @default directive can only be applied to a field that returns a scalar or enum type.
• The @default directive cannot be applied to overridden fields. In this case, apply the directive to the base interface field.

In case of violation of any restriction, the directive will be ignored.

In case of a field is marked with several directives at once - @default, @required, @primaryKey, the behavior of the Kobby Plugin is undefined!