async-graphql/src/resolver_utils/object.rs

289 lines
12 KiB
Rust
Raw Normal View History

2020-09-12 09:29:52 +00:00
use crate::extensions::{ErrorLogger, Extension, ResolveInfo};
use crate::parser::types::Selection;
use crate::registry::MetaType;
use crate::{Context, ContextSelectionSet, Error, OutputValueType, QueryError, Result, Value};
use futures::TryFutureExt;
use std::future::Future;
use std::pin::Pin;
/// A GraphQL object.
///
/// This helper trait allows the type to call `resolve_object` on itself in its
/// `OutputValueType::resolve` implementation.
#[async_trait::async_trait]
pub trait ObjectType: OutputValueType {
/// This function returns true of type `EmptyMutation` only
#[doc(hidden)]
fn is_empty() -> bool {
false
}
/// Resolves a field value and outputs it as a json value `serde_json::Value`.
async fn resolve_field(&self, ctx: &Context<'_>) -> Result<serde_json::Value>;
/// Collect all the fields of the object that are queried in the selection set.
///
/// Objects do not have to override this, but interfaces and unions must call it on their
/// internal type.
fn collect_all_fields<'a>(
&'a self,
ctx: &ContextSelectionSet<'a>,
fields: &mut Fields<'a>,
) -> Result<()>
where
Self: Sized + Send + Sync,
{
fields.add_set(ctx, self)
}
/// Query entities with params
async fn find_entity(&self, ctx: &Context<'_>, _params: &Value) -> Result<serde_json::Value> {
2020-09-12 16:42:15 +00:00
Err(QueryError::EntityNotFound.into_error(ctx.item.pos))
2020-09-12 09:29:52 +00:00
}
}
#[async_trait::async_trait]
impl<T: ObjectType + Send + Sync> ObjectType for &T {
async fn resolve_field(&self, ctx: &Context<'_>) -> Result<serde_json::Value> {
T::resolve_field(*self, ctx).await
}
}
// TODO: reduce code duplication between the two below functions?
/// Resolve an object by executing each of the fields concurrently.
pub async fn resolve_object<'a, T: ObjectType + Send + Sync>(
ctx: &ContextSelectionSet<'a>,
root: &'a T,
) -> Result<serde_json::Value> {
let mut fields = Fields(Vec::new());
fields.add_set(ctx, root)?;
let futures = fields.0;
let res = futures::future::try_join_all(futures).await?;
let mut map = serde_json::Map::new();
for (name, value) in res {
if let serde_json::Value::Object(b) = value {
if let Some(serde_json::Value::Object(a)) = map.get_mut(&name) {
a.extend(b);
} else {
map.insert(name, b.into());
}
} else {
map.insert(name, value);
}
}
Ok(map.into())
}
/// Resolve an object by executing each of the fields serially.
pub async fn resolve_object_serial<'a, T: ObjectType + Send + Sync>(
ctx: &ContextSelectionSet<'a>,
root: &'a T,
) -> Result<serde_json::Value> {
let mut fields = Fields(Vec::new());
fields.add_set(ctx, root)?;
let futures = fields.0;
let mut map = serde_json::Map::new();
for field in futures {
let (name, value) = field.await?;
if let serde_json::Value::Object(b) = value {
if let Some(serde_json::Value::Object(a)) = map.get_mut(&name) {
a.extend(b);
} else {
map.insert(name, b.into());
}
} else {
map.insert(name, value);
}
}
Ok(map.into())
}
type BoxFieldFuture<'a> =
Pin<Box<dyn Future<Output = Result<(String, serde_json::Value)>> + 'a + Send>>;
/// A set of fields on an object.
pub struct Fields<'a>(Vec<BoxFieldFuture<'a>>);
impl<'a> Fields<'a> {
/// Add another set of fields to this set of fields using the given object.
pub fn add_set<T: ObjectType + Send + Sync>(
&mut self,
ctx: &ContextSelectionSet<'a>,
root: &'a T,
) -> Result<()> {
for selection in &ctx.item.node.items {
if ctx.is_skip(&selection.node.directives())? {
continue;
}
match &selection.node {
Selection::Field(field) => {
if field.node.name.node == "__typename" {
// Get the typename
let ctx_field = ctx.with_field(field);
let field_name = ctx_field
.item
.node
.response_key()
.node
.clone()
.into_string();
let typename = root.introspection_type_name().into_owned();
self.0.push(Box::pin(async move {
Ok((field_name, serde_json::Value::String(typename)))
}));
continue;
}
if ctx.is_ifdef(&field.node.directives) {
if let Some(MetaType::Object { fields, .. }) =
ctx.schema_env.registry.types.get(T::type_name().as_ref())
{
if !fields.contains_key(field.node.name.node.as_str()) {
continue;
}
}
}
self.0.push(Box::pin({
let ctx = ctx.clone();
async move {
let ctx_field = ctx.with_field(field);
let field_name = ctx_field
.item
.node
.response_key()
.node
.clone()
.into_string();
let resolve_info = ResolveInfo {
resolve_id: ctx_field.resolve_id,
path_node: ctx_field.path_node.as_ref().unwrap(),
context: &ctx_field,
parent_type: &T::type_name(),
return_type: match ctx_field
.schema_env
.registry
.types
.get(T::type_name().as_ref())
.and_then(|ty| ty.field_by_name(field.node.name.node.as_str()))
.map(|field| &field.ty)
{
Some(ty) => &ty,
None => {
return Err(Error::Query {
pos: field.pos,
path: None,
err: QueryError::FieldNotFound {
field_name: field
.node
.name
.node
.clone()
.into_string(),
object: T::type_name().to_string(),
},
})
}
},
};
ctx_field
.query_env
.extensions
.lock()
.resolve_start(&resolve_info);
let res = root
.resolve_field(&ctx_field)
.map_ok(move |value| (field_name, value))
.await
.log_error(&ctx_field.query_env.extensions)?;
ctx_field
.query_env
.extensions
.lock()
.resolve_end(&resolve_info);
Ok(res)
}
}));
}
selection => {
let (type_condition, selection_set) = match selection {
Selection::Field(_) => unreachable!(),
Selection::FragmentSpread(spread) => {
let fragment = ctx
.query_env
.document
.fragments
.get(&spread.node.fragment_name.node);
let fragment = match fragment {
Some(fragment) => fragment,
None => {
return Err(Error::Query {
pos: spread.pos,
path: None,
err: QueryError::UnknownFragment {
name: spread.node.fragment_name.to_string(),
},
})
}
};
(
Some(&fragment.node.type_condition),
&fragment.node.selection_set,
)
}
Selection::InlineFragment(fragment) => (
fragment.node.type_condition.as_ref(),
&fragment.node.selection_set,
),
};
let type_condition =
type_condition.map(|condition| condition.node.on.node.as_str());
let introspection_type_name = root.introspection_type_name();
2020-09-12 16:07:46 +00:00
let applies_concrete_object = type_condition.map_or(false, |condition| {
2020-09-12 09:29:52 +00:00
introspection_type_name == condition
|| ctx
.schema_env
.registry
.implements
.get(&*introspection_type_name)
.map_or(false, |interfaces| interfaces.contains(condition))
2020-09-12 16:07:46 +00:00
});
if applies_concrete_object {
2020-09-12 09:29:52 +00:00
// The fragment applies to the concrete object type.
// TODO: This solution isn't ideal. If there are two interfaces InterfaceA
// and InterfaceB and one type MyObj that implements both, then if you have
// a type condition for `InterfaceA` on an `InterfaceB` and when resolving,
// the `InterfaceB` is actually a `MyObj` then the contents of the fragment
// will be treated as a `MyObj` rather than an `InterfaceB`. Example:
//
// myObjAsInterfaceB {
// ... on InterfaceA {
// # here you can query MyObj fields even when you should only be
// # able to query InterfaceA fields.
// }
// }
root.collect_all_fields(&ctx.with_selection_set(selection_set), self)?;
} else if type_condition.map_or(true, |condition| T::type_name() == condition) {
// The fragment applies to an interface type.
self.add_set(&ctx.with_selection_set(selection_set), root)?;
}
}
}
}
Ok(())
}
}