Attribute Macro ComplexObject

#[ComplexObject]

Define a complex GraphQL object for SimpleObject’s complex field resolver.

See also the Book.

Sometimes most of the fields of a GraphQL object simply return the value of the structure member, but a few fields are calculated. Usually we use the Object macro to define such a GraphQL object.

But this can be done more beautifully with the ComplexObject macro. We can use the SimpleObject macro to define some simple fields, and use the ComplexObject macro to define some other fields that need to be calculated.

Macro attributes

Attribute	description	Type	Optional
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
guard	Field of guard See also the Book	string	Y
inaccessible	Indicate that an object 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
skip	Skip this field	bool	Y
name	Field name	string	Y
desc	Field description	string	Y
deprecation	Field deprecated	bool	Y
deprecation	Field deprecation reason	string	Y
cache_control	Field cache control	CacheControl	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
shareable	Indicate that a field is allowed to be resolved by multiple subgraphs	bool	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
override_from	Mark the field as overriding a field currently present on another subgraph. It is used to migrate fields between subgraphs.	string	Y
guard	Field of guard See also the Book	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
complexity	Custom field complexity. See also the Book.	bool	Y
complexity	Custom field complexity.	string	Y
derived	Generate derived fields See also the Book.	object	Y
flatten	Similar to serde (flatten)	boolean	Y

Field argument attributes

Attribute	description	Type	Optional
name	Argument name	string	Y
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
validator	Input value validator See also the Book	object	Y
inaccessible	Indicate that a field 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
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
process_with	Upon successful parsing, invokes specified function. Its signature must be fn(&mut T).	code path	Y

Examples

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
    }
}

struct Query;

#[Object]
impl Query {
    async fn obj(&self) -> MyObj {
        MyObj { a: 10, b: 20 }
    }
}

let schema = Schema::new(Query, EmptyMutation, EmptySubscription);
let res = schema.execute("{ obj { a b c } }").await.into_result().unwrap().data;
assert_eq!(res, value!({
    "obj": {
        "a": 10,
        "b": 20,
        "c": 30,
    },
}));