async-graphql/src/resolver.rs
2020-03-25 11:39:28 +08:00

92 lines
3.1 KiB
Rust

use crate::base::BoxFieldFuture;
use crate::{ContextSelectionSet, Error, ErrorWithPosition, ObjectType, QueryError, Result};
use futures::{future, TryFutureExt};
use graphql_parser::query::{Selection, TypeCondition};
use std::iter::FromIterator;
#[allow(missing_docs)]
pub async fn do_resolve<'a, T: ObjectType + Send + Sync>(
ctx: &'a ContextSelectionSet<'a>,
root: &'a T,
) -> Result<serde_json::Value> {
let mut futures = Vec::new();
collect_fields(ctx.clone(), root, &mut futures)?;
let res = futures::future::try_join_all(futures).await?;
let map = serde_json::Map::from_iter(res);
Ok(map.into())
}
#[allow(missing_docs)]
pub fn collect_fields<'a, T: ObjectType + Send + Sync>(
ctx: ContextSelectionSet<'a>,
root: &'a T,
futures: &mut Vec<BoxFieldFuture<'a>>,
) -> Result<()> {
if ctx.items.is_empty() {
anyhow::bail!(QueryError::MustHaveSubFields {
object: T::type_name().to_string(),
}
.with_position(ctx.span.0));
}
for selection in &ctx.item.items {
match selection {
Selection::Field(field) => {
if ctx.is_skip(&field.directives)? {
continue;
}
let ctx_field = ctx.with_item(field);
let field_name = ctx_field.result_name();
if field.name.as_str() == "__typename" {
// Get the typename
futures.push(Box::pin(
future::ok::<serde_json::Value, Error>(T::type_name().to_string().into())
.map_ok(move |value| (field_name, value)),
));
continue;
}
futures.push(Box::pin({
let ctx_field = ctx_field.clone();
async move {
root.resolve_field(&ctx_field, field)
.map_ok(move |value| (field_name, value))
.await
}
}))
}
Selection::FragmentSpread(fragment_spread) => {
if ctx.is_skip(&fragment_spread.directives)? {
continue;
}
if let Some(fragment) = ctx.fragments.get(&fragment_spread.fragment_name) {
collect_fields(ctx.with_item(&fragment.selection_set), root, futures)?;
} else {
return Err(QueryError::UnknownFragment {
name: fragment_spread.fragment_name.clone(),
}
.into());
}
}
Selection::InlineFragment(inline_fragment) => {
if ctx.is_skip(&inline_fragment.directives)? {
continue;
}
if let Some(TypeCondition::On(name)) = &inline_fragment.type_condition {
root.collect_inline_fields(
name,
ctx.with_item(&inline_fragment.selection_set),
futures,
)?;
}
}
}
}
Ok(())
}