1.9 KiB
1.9 KiB
Interface
Interface
is used to abstract Object
s with common fields.
Async-graphql
implements it as a wrapper.
The wrapper will forward field resolution to the Object
that implements this Interface
.
Therefore, the Object
's fields' type and arguments must match with the Interface
's.
Async-graphql
implements auto conversion from Object
to Interface
, you only need to call Into::into
.
Interface field names are transformed to camelCase for the schema definition.
If you need e.g. a snake_cased GraphQL field name, you can use both the name
and method
attributes.
- When
name
andmethod
exist together,name
is the GraphQL field name and themethod
is the resolver function name. - When only
name
exists,name.to_camel_case()
is the GraphQL field name and thename
is the resolver function name.
use async_graphql::*;
struct Circle {
radius: f32,
}
#[Object]
impl Circle {
async fn area(&self) -> f32 {
std::f32::consts::PI * self.radius * self.radius
}
async fn scale(&self, s: f32) -> Shape {
Circle { radius: self.radius * s }.into()
}
#[field(name = "short_description")]
async fn short_description(&self) -> String {
"Circle".to_string()
}
}
struct Square {
width: f32,
}
#[Object]
impl Square {
async fn area(&self) -> f32 {
self.width * self.width
}
async fn scale(&self, s: f32) -> Shape {
Square { width: self.width * s }.into()
}
#[field(name = "short_description")]
async fn short_description(&self) -> String {
"Square".to_string()
}
}
#[derive(Interface)]
#[graphql(
field(name = "area", type = "f32"),
field(name = "scale", type = "Shape", arg(name = "s", type = "f32"))
field(name = "short_description", method = "short_description", type = "String")
)]
enum Shape {
Circle(Circle),
Square(Square),
}