refactor(ws server): impl IdProvider for Box<T> (#684)

* refactor(ws server): set_id_provider `Box<dyn>` * address grumbles: thanks James * relax trait bounds with ?Sized * Update ws-server/src/tests.rs * add docs
paritytech · Feb 1, 2022 · 425ae56 · 425ae56
1 parent 2864756
commit 425ae56
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Showing 5 changed files with 30 additions and 13 deletions.
diff --git a/core/Cargo.toml b/core/Cargo.toml
@@ -10,8 +10,8 @@ license = "MIT"
 anyhow = "1"
 arrayvec = "0.7.1"
 async-trait = "0.1"
-beef = { version = "0.5.1", features = ["impl_serde"] }
 async-channel = { version = "1.6", optional = true }
+beef = { version = "0.5.1", features = ["impl_serde"] }
 thiserror = "1"
 futures-channel = { version = "0.3.14", default-features = false }
 futures-util = { version = "0.3.14", default-features = false, optional = true }

diff --git a/core/src/id_providers.rs b/core/src/id_providers.rs
@@ -31,7 +31,7 @@ use crate::traits::IdProvider;
 use jsonrpsee_types::SubscriptionId;
 
 /// Generates random integers as subscription ID.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct RandomIntegerIdProvider;
 
 impl IdProvider for RandomIntegerIdProvider {
@@ -42,7 +42,7 @@ impl IdProvider for RandomIntegerIdProvider {
 }
 
 /// Generates random strings of length `len` as subscription ID.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct RandomStringIdProvider {
 	len: usize,
 }
@@ -62,7 +62,7 @@ impl IdProvider for RandomStringIdProvider {
 }
 
 /// No-op implementation to be used for servers that don't support subscriptions.
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub struct NoopIdProvider;
 
 impl IdProvider for NoopIdProvider {

diff --git a/core/src/traits.rs b/core/src/traits.rs
@@ -71,7 +71,18 @@ tuple_impls! {
 }
 
 /// Trait to generate subscription IDs.
-pub trait IdProvider: Send + Sync {
+pub trait IdProvider: Send + Sync + std::fmt::Debug {
 	/// Returns the next ID for the subscription.
 	fn next_id(&self) -> SubscriptionId<'static>;
 }
+
+// Implement `IdProvider` for `Box<T>`
+//
+// It's not implemented for `&'_ T` because
+// of the required `'static lifetime`
+// Thus, `&dyn IdProvider` won't work.
+impl<T: IdProvider + ?Sized> IdProvider for Box<T> {
+	fn next_id(&self) -> SubscriptionId<'static> {
+		(**self).next_id()
+	}
+}
diff --git a/ws-server/src/server.rs b/ws-server/src/server.rs
@@ -70,6 +70,8 @@ impl<M> std::fmt::Debug for Server<M> {
 			.field("listener", &self.listener)
 			.field("cfg", &self.cfg)
 			.field("stop_monitor", &self.stop_monitor)
+			.field("id_provider", &self.id_provider)
+			.field("resources", &self.resources)
 			.finish()
 	}
 }
@@ -644,19 +646,14 @@ impl Default for Settings {
 }
 
 /// Builder to configure and create a JSON-RPC Websocket server
+#[derive(Debug)]
 pub struct Builder<M = ()> {
 	settings: Settings,
 	resources: Resources,
 	middleware: M,
 	id_provider: Arc<dyn IdProvider>,
 }
 
-impl<M> std::fmt::Debug for Builder<M> {
-	fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-		f.debug_struct("Builder").field("settings", &self.settings).field("resources", &self.resources).finish()
-	}
-}
-
 impl Default for Builder {
 	fn default() -> Self {
 		Builder {
@@ -810,16 +807,24 @@ impl<M> Builder<M> {
 	/// Configure custom `subscription ID` provider for the server to use
 	/// to when getting new subscription calls.
 	///
+	/// You may choose static dispatch or dynamic dispatch because
+	/// `IdProvider` is implemented for `Box<T>`.
+	///
 	/// Default: [`RandomIntegerIdProvider`].
 	///
 	/// # Examples
 	///
 	/// ```rust
 	/// use jsonrpsee_ws_server::{WsServerBuilder, RandomStringIdProvider, IdProvider};
 	///
-	/// let builder = WsServerBuilder::default().set_id_provider(RandomStringIdProvider::new(16));
+	/// // static dispatch
+	/// let builder1 = WsServerBuilder::default().set_id_provider(RandomStringIdProvider::new(16));
+	///
+	/// // or dynamic dispatch
+	/// let builder2 = WsServerBuilder::default().set_id_provider(Box::new(RandomStringIdProvider::new(16)));
 	/// ```
-	pub fn set_id_provider(mut self, id_provider: impl IdProvider + 'static) -> Self {
+	///
+	pub fn set_id_provider<I: IdProvider + 'static>(mut self, id_provider: I) -> Self {
 		self.id_provider = Arc::new(id_provider);
 		self
 	}

diff --git a/ws-server/src/tests.rs b/ws-server/src/tests.rs
@@ -632,6 +632,7 @@ async fn unsubscribe_wrong_sub_id_type() {
 
 #[tokio::test]
 async fn custom_subscription_id_works() {
+	#[derive(Debug, Clone)]
 	struct HardcodedSubscriptionId;
 
 	impl IdProvider for HardcodedSubscriptionId {