#[derive(Interface)]
{
// Attributes available to this derive:
#[graphql]
}
Expand description
Define a GraphQL interface
§Macro attributes
Attribute | description | Type | Optional |
---|---|---|---|
name | Object name | string | Y |
name_type | If true , the interface name will be specified from async_graphql::TypeName trait | bool | Y |
rename_fields | Rename all the fields according to the given case convention. The possible values are “lowercase”, “UPPERCASE”, “PascalCase”, “camelCase”, “snake_case”, “SCREAMING_SNAKE_CASE”. | string | Y |
rename_args | Rename all the arguments according to the given case convention. The possible values are “lowercase”, “UPPERCASE”, “PascalCase”, “camelCase”, “snake_case”, “SCREAMING_SNAKE_CASE”. | string | Y |
field | Fields of this Interface | InterfaceField | N |
extends | Add fields to an entity that’s defined in another service | bool | Y |
visible | If false , it will not be displayed in introspection. See also the Book. | bool | Y |
visible | Call the specified function. If the return value is false , it will not be displayed in introspection. | string | Y |
inaccessible | Indicate that an interface is not accessible from a supergraph when using Apollo Federation | bool | Y |
tag | Arbitrary string metadata that will be propagated to the supergraph when using Apollo Federation. This attribute is repeatable | string | Y |
§Field attributes
Attribute | description | Type | Optional |
---|---|---|---|
name | Field name | string | N |
ty | Field type | string | N |
method | Rust resolver method name. If specified, name will not be camelCased in schema definition | string | Y |
desc | Field description | string | Y |
deprecation | Field deprecated | bool | Y |
deprecation | Field deprecation reason | string | Y |
arg | Field arguments | InterfaceFieldArgument | Y |
external | Mark a field as owned by another service. This allows service A to use fields from service B while also knowing at runtime the types of that field. | bool | Y |
provides | Annotate the expected returned fieldset from a field on a base type that is guaranteed to be selectable by the gateway. | string | Y |
requires | Annotate the required input fieldset from a base type for a resolver. It is used to develop a query plan where the required fields may not be needed by the client, but the service may need additional information from other services. | string | Y |
override_from | Mark the field as overriding a field currently present on another subgraph. It is used to migrate fields between subgraphs. | string | Y |
visible | If false , it will not be displayed in introspection. See also the Book. | bool | Y |
visible | Call the specified function. If the return value is false , it will not be displayed in introspection. | string | Y |
inaccessible | Indicate that a field is not accessible from a supergraph when using Apollo Federation | bool | Y |
tag | Arbitrary string metadata that will be propagated to the supergraph when using Apollo Federation. This attribute is repeatable | string | Y |
§Field argument attributes
Attribute | description | Type | Optional |
---|---|---|---|
name | Argument name | string | N |
ty | Argument type | string | N |
desc | Argument description | string | Y |
default | Use Default::default for default value | none | Y |
default | Argument default value | literal | Y |
default_with | Expression to generate default value | code string | Y |
visible | If false , it will not be displayed in introspection. See also the Book. | bool | Y |
visible | Call the specified function. If the return value is false , it will not be displayed in introspection. | string | Y |
secret | Mark this field as a secret, it will not output the actual value in the log. | bool | Y |
inaccessible | Indicate that an argument is not accessible from a supergraph when using Apollo Federation | bool | Y |
tag | Arbitrary string metadata that will be propagated to the supergraph when using Apollo Federation. This attribute is repeatable | string | Y |
§Define an interface
Define TypeA, TypeB, TypeC… Implement the MyInterface
ⓘ
#[derive(Interface)]
enum MyInterface {
TypeA(TypeA),
TypeB(TypeB),
TypeC(TypeC),
...
}
§Fields
The type, name, and parameter fields of the interface must exactly match the type of the implementation interface, but Result can be omitted.
use async_graphql::*;
struct TypeA {
value: i32,
}
#[Object]
impl TypeA {
/// Returns data borrowed from the context
async fn value_a<'a>(&self, ctx: &'a Context<'_>) -> Result<&'a str> {
Ok(ctx.data::<String>()?.as_str())
}
/// Returns data borrowed self
async fn value_b(&self) -> &i32 {
&self.value
}
/// With parameters
async fn value_c(&self, a: i32, b: i32) -> i32 {
a + b
}
/// Disabled name transformation, don't forget "method" argument in interface!
#[graphql(name = "value_d")]
async fn value_d(&self) -> i32 {
&self.value + 1
}
}
#[derive(Interface)]
#[graphql(
field(name = "value_a", ty = "&'ctx str"),
field(name = "value_b", ty = "&i32"),
field(name = "value_c", ty = "i32",
arg(name = "a", ty = "i32"),
arg(name = "b", ty = "i32")),
field(name = "value_d", method = "value_d", ty = "i32"),
)]
enum MyInterface {
TypeA(TypeA)
}
struct Query;
#[Object]
impl Query {
async fn type_a(&self) -> MyInterface {
TypeA { value: 10 }.into()
}
}
let schema = Schema::build(Query, EmptyMutation, EmptySubscription).data("hello".to_string()).finish();
let res = schema.execute(r#"
{
typeA {
valueA
valueB
valueC(a: 3, b: 2)
value_d
}
}"#).await.into_result().unwrap().data;
assert_eq!(res, value!({
"typeA": {
"valueA": "hello",
"valueB": 10,
"valueC": 5,
"value_d": 11
}
}));