SimpleObject

SimpleObject directly maps all the fields of a struct to GraphQL object. If you don't require automatic mapping of fields, see Object.

The example below defines an object MyObject which includes the fields a and b. c will be not mapped to GraphQL as it is labelled as #[graphql(skip)]

#![allow(unused)]
fn main() {
extern crate async_graphql;
use async_graphql::*;

#[derive(SimpleObject)]
struct MyObject {
    /// Value a
    a: i32,

    /// Value b
    b: i32,

    #[graphql(skip)]
    c: i32,
}
}

User-defined resolvers

Sometimes most of the fields of a GraphQL object simply return the value of the structure member, but a few fields are calculated. In this case, the Object macro cannot be used unless you hand-write all the resolvers.

The ComplexObject macro works in conjunction with the SimpleObject macro. The SimpleObject derive macro defines the non-calculated fields, where as the ComplexObject macro let's you write user-defined resolvers for the calculated fields.

Resolvers added to ComplexObject adhere to the same rules as resolvers of Object.

#![allow(unused)]
fn main() {
extern crate async_graphql;
use async_graphql::*;
#[derive(SimpleObject)]
#[graphql(complex)] // NOTE: If you want the `ComplexObject` macro to take effect, this `complex` attribute is required.
struct MyObj {
    a: i32,
    b: i32,
}

#[ComplexObject]
impl MyObj {
    async fn c(&self) -> i32 {
        self.a + self.b
    }
}
}

Used for both input and output

#![allow(unused)]
fn main() {
extern crate async_graphql;
use async_graphql::*;
#[derive(SimpleObject, InputObject)]
#[graphql(input_name = "MyObjInput")] // Note: You must use the input_name attribute to define a new name for the input type, otherwise a runtime error will occur.
struct MyObj {
    a: i32,
    b: i32,
}
}

Flatten fields

You can flatten fields by adding #[graphql(flatten)], i.e.:

#![allow(unused)]
fn main() {
extern crate async_graphql;
use async_graphql::*;
#[derive(SimpleObject)]
pub struct ChildObject {
    b: String,
    c: String,
}

#[derive(SimpleObject)]
pub struct ParentObject {
    a: String,
    #[graphql(flatten)]
    child: ChildObject,
}

// Is the same as

#[derive(SimpleObject)]
pub struct Object {
    a: String,
    b: String,
    c: String,
}
}