Struct Union 

pub struct Union { /* private fields */ }

Available on crate feature dynamic-schema only.

A GraphQL union type

Examples

use async_graphql::{dynamic::*, value, Value};

let obj_a = Object::new("MyObjA")
    .field(Field::new("a", TypeRef::named_nn(TypeRef::INT), |_| {
        FieldFuture::new(async { Ok(Some(Value::from(100))) })
    }))
    .field(Field::new("b", TypeRef::named_nn(TypeRef::INT), |_| {
        FieldFuture::new(async { Ok(Some(Value::from(200))) })
    }));

let obj_b = Object::new("MyObjB")
    .field(Field::new("c", TypeRef::named_nn(TypeRef::INT), |_| {
        FieldFuture::new(async { Ok(Some(Value::from(300))) })
    }))
    .field(Field::new("d", TypeRef::named_nn(TypeRef::INT), |_| {
        FieldFuture::new(async { Ok(Some(Value::from(400))) })
    }));

let union = Union::new("MyUnion")
    .possible_type(obj_a.type_name())
    .possible_type(obj_b.type_name());

let query = Object::new("Query")
    .field(Field::new("valueA", TypeRef::named_nn(union.type_name()), |_| {
        FieldFuture::new(async {
            Ok(Some(FieldValue::with_type(FieldValue::NULL, "MyObjA")))
        })
    }))
    .field(Field::new("valueB", TypeRef::named_nn(union.type_name()), |_| {
        FieldFuture::new(async {
            Ok(Some(FieldValue::with_type(FieldValue::NULL, "MyObjB")))
        })
    }));


let schema = Schema::build(query.type_name(), None, None)
    .register(obj_a)
    .register(obj_b)
    .register(union)
    .register(query)
    .finish()?;

let query = r#"
    {
        valueA { ... on MyObjA { a b } ... on MyObjB { c d } }
        valueB { ... on MyObjA { a b } ... on MyObjB { c d } }
    }
"#;

assert_eq!(
    schema.execute(query).await.into_result().unwrap().data,
    value!({
        "valueA": {
            "a": 100,
            "b": 200,
        },
        "valueB": {
            "c": 300,
            "d": 400,
        }
    })
);

Implementations

impl Union

pub fn new(name: impl Into<String>) -> Self

Create a GraphQL union type

pub fn description(self, description: impl Into<String>) -> Self

Set the description

pub fn inaccessible(self) -> Self

Indicate that an enum is not accessible from a supergraph when using Apollo Federation

Reference: https://www.apollographql.com/docs/federation/federated-types/federated-directives/#inaccessible

pub fn tags<I: IntoIterator<Item = T>, T: Into<String>>(self, tags: I) -> Self

Arbitrary string metadata that will be propagated to the supergraph when using Apollo Federation. This attribute is repeatable

Reference: https://www.apollographql.com/docs/federation/federated-types/federated-directives/#applying-metadata

pub fn directive(self, directive: Directive) -> Self

Attach directive to the entity

pub fn possible_type(self, ty: impl Into<String>) -> Self

Add a possible type to the union that must be an object

pub fn type_name(&self) -> &str

Returns the type name

Trait Implementations

impl Debug for Union

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl From<Union> for Type

fn from(union: Union) -> Self

Converts to this type from the input type.