Attribute Macro async_graphql::Object[−][src]

#[Object]

Expand description

Define a GraphQL object with methods

See also the Book.

All methods are converted to camelCase.

Macro parameters

Attribute	description	Type	Optional
name	Object name	string	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
cache_control	Object cache control	`CacheControl`	Y
extends	Add fields to an entity that’s defined in another service	bool	Y
use_type_description	Specifies that the description of the type is on the type declaration. `Description`(derive.Description.html)	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

Field parameters

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
guard	Field of guard	`Guard`	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

Field argument parameters

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	`InputValueValidator`	Y
complexity	Custom field complexity. See also the Book.	bool	Y
complexity	Custom field complexity.	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
serial	Resolve each field sequentially.	bool	Y
key	Is entity key(for Federation)	bool	Y

Valid field return types

Scalar values, such as i32 and bool. usize, isize, u128 and i128 are not supported
Vec<T>, such as Vec<i32>
Slices, such as &[i32]
Option<T>, such as Option<i32>
BTree<T>, HashMap<T>, HashSet<T>, BTreeSet<T>, LinkedList<T>, VecDeque<T>
GraphQL objects.
GraphQL enums.
References to any of the above types, such as &i32 or &Option<String>.
Result<T, E>, such as Result<i32, E>

Context

You can define a context as an argument to a method, and the context should be the first argument to the method.

#[Object]
impl QueryRoot {
    async fn value(&self, ctx: &Context<'_>) -> { ... }
}

Examples

Implements GraphQL Object for struct.

use async_graphql::*;

struct QueryRoot {
    value: i32,
}

#[Object]
impl QueryRoot {
    /// value
    async fn value(&self) -> i32 {
        self.value
    }

    /// reference value
    async fn value_ref(&self) -> &i32 {
        &self.value
    }

    /// value with error
    async fn value_with_error(&self) -> Result<i32> {
        Ok(self.value)
    }

    async fn value_with_arg(&self, #[graphql(default = 1)] a: i32) -> i32 {
        a
    }
}

tokio::runtime::Runtime::new().unwrap().block_on(async move {
    let schema = Schema::new(QueryRoot { value: 10 }, EmptyMutation, EmptySubscription);
    let res = schema.execute(r#"{
        value
        valueRef
        valueWithError
        valueWithArg1: valueWithArg
        valueWithArg2: valueWithArg(a: 99)
    }"#).await.into_result().unwrap().data;
    assert_eq!(res, value!({
        "value": 10,
        "valueRef": 10,
        "valueWithError": 10,
        "valueWithArg1": 1,
        "valueWithArg2": 99
    }));
});

Examples

Implements GraphQL Object for trait object.

use async_graphql::*;

trait MyTrait: Send + Sync {
    fn name(&self) -> &str;
}

#[Object]
impl dyn MyTrait {
    #[graphql(name = "name")]
    async fn gql_name(&self) -> &str {
        self.name()
    }
}

struct MyObj(String);

impl MyTrait for MyObj {
    fn name(&self) -> &str {
        &self.0
    }
}

struct QueryRoot;

#[Object]
impl QueryRoot {
    async fn objs(&self) -> Vec<Box<dyn MyTrait>> {
        vec![
            Box::new(MyObj("a".to_string())),
            Box::new(MyObj("b".to_string())),
        ]
    }
}

tokio::runtime::Runtime::new().unwrap().block_on(async move {
    let schema = Schema::new(QueryRoot, EmptyMutation, EmptySubscription);
    let res = schema.execute("{ objs { name } }").await.into_result().unwrap().data;
    assert_eq!(res, value!({
        "objs": [
            { "name": "a" },
            { "name": "b" },
        ]
    }));
});