async-graphql/src/types/empty_subscription.rs

50 lines
1.4 KiB
Rust

use std::borrow::Cow;
use std::pin::Pin;
use futures_util::stream::{self, Stream};
use crate::{registry, Context, Response, ServerError, SubscriptionType, Type};
/// 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,
visible: None,
})
}
}
impl SubscriptionType for EmptySubscription {
fn is_empty() -> bool {
true
}
fn create_field_stream<'a>(
&'a self,
ctx: &'a Context<'_>,
) -> Option<Pin<Box<dyn Stream<Item = Response> + Send + 'a>>>
where
Self: Send + Sync + 'static + Sized,
{
Some(Box::pin(stream::once(async move {
let err = ServerError::new("Schema is not configured for mutations.").at(ctx.item.pos);
Response::from_errors(vec![err])
})))
}
}