Derive Macro GraphQLInterface

#[derive(GraphQLInterface)]
{
    // Attributes available to this derive:
    #[graphql]
}

#[derive(GraphQLInterface)] macro for generating a GraphQL interface implementation for traits and its implementers.

This macro is applicable only to structs and useful in case interface fields don’t have any arguments:

use juniper::{GraphQLInterface, GraphQLObject};

// NOTICE: By default a `CharacterValue` enum is generated by macro to represent values of this
//         GraphQL interface.
#[derive(GraphQLInterface)]
#[graphql(for = Human)] // enumerating all implementers is mandatory
struct Character {
    id: String,
}

#[derive(GraphQLObject)]
#[graphql(impl = CharacterValue)] // notice the enum type name, not trait name
struct Human {
    id: String, // this field is used to resolve Character::id
    home_planet: String,
}

For more info and possibilities see #[graphql_interface] macro.