Attribute Macro async_graphql::GQLSubscription

#[GQLSubscription]

Define a GraphQL subscription

See also the Book.

The field function is a synchronization function that performs filtering. When true is returned, the message is pushed to the client. The second parameter is the type of the field. Starting with the third parameter is one or more filtering conditions, The filter condition is the parameter of the field. The filter function should be synchronous.

Macro parameters

Attribute	description	Type	Optional
name	Object name	string	Y
desc	Object description	string	Y

Field parameters

Attribute	description	Type	Optional
name	Field name	string	Y
desc	Field description	string	Y
deprecation	Field deprecation reason	string	Y
guard	Field of guard	Guard	Y
feature	It's like a #[cfg(feature = "foo")] attribute but instead of not compiling this field it will just return a proper FieldError to tell you this feature is not enabled	string ("feature1,feature2")	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

Examples

use async_graphql::*;
use futures::{Stream, StreamExt};

struct SubscriptionRoot;

#[GQLSubscription]
impl SubscriptionRoot {
    async fn value(&self, condition: i32) -> impl Stream<Item = i32> {
        // Returns the number from 0 to `condition`.
        futures::stream::iter(0..condition)
    }
}