async-graphql/src/types/deferred.rs

96 lines
3.3 KiB
Rust

use crate::context::DeferList;
use crate::registry::Registry;
use crate::{ContextSelectionSet, OutputValueType, Positioned, QueryResponse, Result, Type};
use async_graphql_parser::query::Field;
use itertools::Itertools;
use parking_lot::Mutex;
use std::borrow::Cow;
use std::sync::atomic::AtomicUsize;
/// Deferred type
///
/// Allows to defer the type of results returned, only takes effect when the @defer directive exists on the field.
pub struct Deferred<T: Type + Send + Sync + 'static>(Mutex<Option<T>>);
impl<T: Type + Send + Sync + 'static> From<T> for Deferred<T> {
fn from(value: T) -> Self {
Self(Mutex::new(Some(value)))
}
}
impl<T: Type + Send + Sync + 'static> Type for Deferred<T> {
fn type_name() -> Cow<'static, str> {
T::type_name()
}
fn create_type_info(registry: &mut Registry) -> String {
T::create_type_info(registry)
}
}
#[async_trait::async_trait]
impl<T: OutputValueType + Send + Sync + 'static> OutputValueType for Deferred<T> {
async fn resolve(
&self,
ctx: &ContextSelectionSet<'_>,
field: &Positioned<Field>,
) -> Result<serde_json::Value> {
let obj = self.0.lock().take();
if let Some(obj) = obj {
if let Some(defer_list) = ctx.defer_list {
if ctx.is_defer(&field.directives) {
let schema_env = ctx.schema_env.clone();
let query_env = ctx.query_env.clone();
let mut field = field.clone();
// remove @defer directive
if let Some((idx, _)) = field
.node
.directives
.iter()
.find_position(|d| d.name.as_str() == "defer")
{
field.node.directives.remove(idx);
}
let path_prefix = ctx
.path_node
.as_ref()
.map(|path| path.to_json())
.unwrap_or_default();
defer_list.append(async move {
let inc_resolve_id = AtomicUsize::default();
let defer_list = DeferList {
path_prefix: path_prefix.clone(),
futures: Default::default(),
};
let ctx = query_env.create_context(
&schema_env,
None,
&field.selection_set,
&inc_resolve_id,
Some(&defer_list),
);
let data = obj.resolve(&ctx, &field).await?;
Ok((
QueryResponse {
path: Some(path_prefix),
data,
extensions: None,
cache_control: Default::default(),
},
defer_list,
))
});
return Ok(serde_json::Value::Null);
}
}
OutputValueType::resolve(&obj, ctx, field).await
} else {
Ok(serde_json::Value::Null)
}
}
}