Fix relay @defer requires a label in the second chunk. #146

async-graphql-warp/src/lib.rs

@@ -93,16 +93,22 @@ where
     let opts = Arc::new(opts);
     warp::any()
         .and(warp::method())
-        .and(warp::query::raw())
+        .and(warp::query::raw().or(warp::any().map(|| String::new())).unify())
         .and(warp::header::optional::<String>("content-type"))
         .and(warp::body::stream())
         .and(warp::any().map(move || opts.clone()))
         .and(warp::any().map(move || schema.clone()))
         .and_then(
-            |method, query: String, content_type, body, opts: Arc<IntoQueryBuilderOpts>, schema| async move {
+            |method,
+             query: String,
+             content_type,
+             body,
+             opts: Arc<IntoQueryBuilderOpts>,
+             schema| async move {
                 if method == Method::GET {
-                    let gql_request: GQLRequest = serde_urlencoded::from_str(&query)
-                        .map_err(|err| warp::reject::custom(BadRequest(err.into())))?;
+                    let gql_request: GQLRequest =
+                        serde_urlencoded::from_str(&query)
+                            .map_err(|err| warp::reject::custom(BadRequest(err.into())))?;
                     let builder = gql_request
                         .into_query_builder_opts(&opts)
                         .await

src/http/mod.rs

@@ -61,6 +61,10 @@ impl Serialize for GQLResponse {
         match &self.0 {
             Ok(res) => {
                 let mut map = serializer.serialize_map(None)?;
+                if let Some(label) = &res.label {
+                    map.serialize_key("label")?;
+                    map.serialize_value(label)?;
+                }
                 if let Some(path) = &res.path {
                     map.serialize_key("path")?;
                     map.serialize_value(path)?;
@@ -215,6 +219,7 @@ mod tests {
     #[test]
     fn test_response_data() {
         let resp = GQLResponse(Ok(QueryResponse {
+            label: None,
             path: None,
             data: json!({"ok": true}),
             extensions: None,

src/query.rs

@@ -9,7 +9,9 @@ use crate::{
 };
 use async_graphql_parser::query::OperationType;
 use futures::{Stream, StreamExt};
+use itertools::Itertools;
 use std::any::Any;
+use std::borrow::Cow;
 use std::fs::File;
 use std::pin::Pin;
 use std::sync::atomic::AtomicUsize;
@@ -41,6 +43,11 @@ pub trait IntoQueryBuilder: Sized {
 /// Query response
 #[derive(Debug)]
 pub struct QueryResponse {
+    /// Label for RelayModernQueryExecutor
+    ///
+    /// https://github.com/facebook/relay/blob/2859aa8df4df7d4d6d9eef4c9dc1134286773710/packages/relay-runtime/store/RelayModernQueryExecutor.js#L1267
+    pub label: Option<String>,
+
     /// Path for subsequent response
     pub path: Option<Vec<serde_json::Value>>,
 
@@ -62,6 +69,19 @@ impl QueryResponse {
         } else {
             self.path = Some(prefix);
         }
+
+        self.label = self.path.as_ref().map(|path| {
+            path.iter()
+                .map(|value| {
+                    if let serde_json::Value::String(s) = value {
+                        Cow::Borrowed(s.as_str())
+                    } else {
+                        Cow::Owned(value.to_string())
+                    }
+                })
+                .join("$")
+        });
+
         self
     }
 
@@ -209,7 +229,15 @@ impl QueryBuilder {
                                 next_path_prefix.extend(defer_list.path_prefix.clone());
                                 next_defer_list.push((next_path_prefix, fut));
                             }
-                            yield res.apply_path_prefix(path_prefix);
+                            let mut new_res = res.apply_path_prefix(path_prefix);
+                            new_res.label = new_res.path.as_ref().map(|path| path.iter().map(|value| {
+                                if let serde_json::Value::String(s) = value {
+                                    s.to_string()
+                                } else {
+                                    value.to_string()
+                                }
+                            }).join("$"));
+                            yield new_res;
                         }
                         if next_defer_list.is_empty() {
                             break;
@@ -290,6 +318,7 @@ impl QueryBuilder {
         env.extensions.execution_end();
 
         let res = QueryResponse {
+            label: None,
             path: None,
             data,
             extensions: env.extensions.result(),

src/subscription/ws_transport.rs

@@ -141,6 +141,7 @@ impl SubscriptionTransport for WebSocketTransport {
                         id: Some(id.clone()),
                         payload: Some(
                             serde_json::to_value(GQLResponse(Ok(QueryResponse {
+                                label: None,
                                 path: None,
                                 data: value,
                                 extensions: None,

src/types/deferred.rs

@@ -76,6 +76,7 @@ impl<T: OutputValueType + Send + Sync + 'static> OutputValueType for Deferred<T>
 
                         Ok((
                             QueryResponse {
+                                label: None,
                                 path: Some(path_prefix),
                                 data,
                                 extensions: None,

src/types/streamed.rs

@@ -87,6 +87,7 @@ impl<T: OutputValueType + Send + Sync + 'static> OutputValueType for Streamed<T>
 
                             Ok((
                                 QueryResponse {
+                                    label: None,
                                     path: Some(path_prefix),
                                     data,
                                     extensions: None,