From 13fc0dadeb61e87b03051439242745fb19c2e384 Mon Sep 17 00:00:00 2001
From: jsus <esseswann@gmail.com>
Date: Fri, 24 Sep 2021 14:35:46 +0300
Subject: [PATCH] Using newtype for context
---
docs/book/content/types/objects/using_contexts.md | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/docs/book/content/types/objects/using_contexts.md b/docs/book/content/types/objects/using_contexts.md
index 1b65771c..a2174ad4 100644
--- a/docs/book/content/types/objects/using_contexts.md
+++ b/docs/book/content/types/objects/using_contexts.md
@@ -101,23 +101,29 @@ For example, when using async runtime with [work stealing][2] (like `tokio`), wh
# use juniper::graphql_object;
use tokio::sync::RwLock;
-impl juniper::Context for Database {}
-
struct Database {
requested_count: HashMap<i32, i32>,
}
+// Since we cannot directly implement juniper::Context
+// for RwLock we use the newtype idiom
+struct DatabaseContext(RwLock<Database>)
+
+impl juniper::Context for DatabaseContext {}
+
struct User {
id: i32,
name: String
}
-#[graphql_object(context=RwLock<Database>)]
+#[graphql_object(context=DatabaseContext)]
impl User {
- async fn times_requested<'db>(&self, context: &'db RwLock<Database>) -> i32 {
+ async fn times_requested<'db>(&self, context: &'db DatabaseContext) -> i32 {
// Acquire a mutable reference and await if async RwLock is used,
// which is necessary if context consists async operations like
// querying remote databases.
+ // Obtain base type
+ let DatabaseContext(context) = context;
// If context is immutable use .read() on RwLock.
let mut context = context.write().await;
// Preform a mutable operation.