async-graphql/src/types/empty_subscription.rs
2020-09-30 07:45:48 +08:00

50 lines
1.4 KiB
Rust

use crate::{registry, Context, Error, Pos, QueryError, Result, SubscriptionType, Type};
use futures::{stream, Stream};
use std::borrow::Cow;
use std::pin::Pin;
/// Empty subscription
///
/// Only the parameters used to construct the Schema, representing an unconfigured subscription.
#[derive(Default, Copy, Clone)]
pub struct EmptySubscription;
impl Type for EmptySubscription {
fn type_name() -> Cow<'static, str> {
Cow::Borrowed("EmptyMutation")
}
fn create_type_info(registry: &mut registry::Registry) -> String {
registry.create_type::<Self, _>(|_| registry::MetaType::Object {
name: "EmptySubscription".to_string(),
description: None,
fields: Default::default(),
cache_control: Default::default(),
extends: false,
keys: None,
})
}
}
impl SubscriptionType for EmptySubscription {
fn is_empty() -> bool {
true
}
fn create_field_stream<'a>(
&'a self,
_ctx: &'a Context<'a>,
) -> Pin<Box<dyn Stream<Item = Result<serde_json::Value>> + Send + 'a>>
where
Self: Send + Sync + 'static + Sized,
{
Box::pin(stream::once(async {
Err(Error::Query {
pos: Pos::default(),
path: None,
err: QueryError::NotConfiguredSubscriptions,
})
}))
}
}