Struct FieldValue

pub struct FieldValue<'a>(/* private fields */);

Available on crate feature dynamic-schema only.

A value returned from the resolver function

Implementations

impl<'a> FieldValue<'a>

pub const NULL: FieldValue<'a> = _

A null value equivalent to FieldValue::Value(Value::Null)

pub const NONE: Option<FieldValue<'a>> = None

A none value equivalent to None::<FieldValue>

It is more convenient to use when your resolver needs to return None.

Examples

use async_graphql::dynamic::*;

let query =
    Object::new("Query").field(Field::new("value", TypeRef::named(TypeRef::INT), |ctx| {
        FieldFuture::new(async move { Ok(FieldValue::NONE) })
    }));

pub const fn none() -> Option<FieldValue<'a>>

Returns a None::<FieldValue> meaning the resolver no results.

pub fn value(value: impl Into<Value>) -> Self

Create a FieldValue from Value

pub fn owned_any<T: Any + Send + Sync>(obj: T) -> Self

Create a FieldValue from owned any value

pub fn boxed_any<T: Any + Send + Sync>(obj: Box<T>) -> Self

Create a FieldValue from unsized any value

pub fn borrowed_any<T: Any + Send + Sync>(obj: &'a T) -> Self

Create a FieldValue from owned any value

pub fn list<I, T>(values: I) -> Self

where I: IntoIterator<Item = T>, T: Into<FieldValue<'a>>,

Create a FieldValue from list

pub fn with_type(self, ty: impl Into<Cow<'static, str>>) -> Self

Create a FieldValue and specify its type, which must be an object

NOTE: Fields of type Interface or Union must return FieldValue::WithType.

Examples

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

struct MyObjData {
    a: i32,
}

let my_obj = Object::new("MyObj").field(Field::new(
    "a",
    TypeRef::named_nn(TypeRef::INT),
    |ctx| FieldFuture::new(async move {
        let data = ctx.parent_value.try_downcast_ref::<MyObjData>()?;
        Ok(Some(Value::from(data.a)))
    }),
));

let my_union = Union::new("MyUnion").possible_type(my_obj.type_name());

let query = Object::new("Query").field(Field::new(
    "obj",
    TypeRef::named_nn(my_union.type_name()),
    |_| FieldFuture::new(async move {
        Ok(Some(FieldValue::owned_any(MyObjData { a: 10 }).with_type("MyObj")))
    }),
));

let schema = Schema::build("Query", None, None)
    .register(my_obj)
    .register(my_union)
    .register(query)
    .finish()
    .unwrap();

assert_eq!(
   schema
       .execute("{ obj { ... on MyObj { a } } }")
       .await
       .into_result()
       .unwrap()
       .data,
   value!({ "obj": { "a": 10 } })
);

pub fn as_value(&self) -> Option<&Value>

If the FieldValue is a value, returns the associated Value. Returns None otherwise.

pub fn try_to_value(&self) -> Result<&Value>

Like as_value, but returns Result.

pub fn as_list(&self) -> Option<&[FieldValue<'_>]>

If the FieldValue is a list, returns the associated vector. Returns None otherwise.

pub fn try_to_list(&self) -> Result<&[FieldValue<'_>]>

Like as_list, but returns Result.

pub fn downcast_ref<T: Any>(&self) -> Option<&T>

If the FieldValue is a any, returns the associated vector. Returns None otherwise.

pub fn try_downcast_ref<T: Any>(&self) -> Result<&T>

Like downcast_ref, but returns Result.

Trait Implementations

impl<'a> Debug for FieldValue<'a>

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

Formats the value using the given formatter.

impl<'a> From<()> for FieldValue<'a>

fn from(_: ()) -> Self

Converts to this type from the input type.

impl<'a> From<ConstValue> for FieldValue<'a>

fn from(value: Value) -> Self

Converts to this type from the input type.

impl<'a, T: Into<FieldValue<'a>>> From<Vec<T>> for FieldValue<'a>

fn from(values: Vec<T>) -> Self

Converts to this type from the input type.