async-graphql/src/docs/subscription.md

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 attributes

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
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
use_type_description	Specifies that the description of the type is on the type declaration. Description(derive.Description.html)	bool	Y
guard	Field of guard See also the Book	string	Y

Field attributes

Attribute	description	Type	Optional
name	Field name	string	Y
deprecation	Field deprecated	bool	Y
deprecation	Field deprecation reason	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
secret	Mark this field as a secret, it will not output the actual value in the log.	bool	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
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
process_with	Upon successful parsing, invokes specified function. Its signature must be fn(&mut T).	code path	Y

Examples

use async_graphql::*;
use futures_util::stream::{Stream, StreamExt};

struct Subscription;

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