4 files changed, 162 insertions, 73 deletions

diff --git a/jsonrpc/src/client/builder.rs b/jsonrpc/src/client/builder.rs
index a287070..2263498 100644
--- a/jsonrpc/src/client/builder.rs
+++ b/jsonrpc/src/client/builder.rs
@@ -1,11 +1,11 @@
-use std::{collections::HashMap, sync::Arc};
+use std::sync::Arc;
 
 #[cfg(feature = "smol")]
 use futures_rustls::rustls;
 #[cfg(feature = "tokio")]
 use tokio_rustls::rustls;
 
-use karyon_core::{async_runtime::lock::Mutex, async_util::TaskGroup};
+use karyon_core::async_util::TaskGroup;
 use karyon_net::{tls::ClientTlsConfig, Conn, Endpoint, ToEndpoint};
 
 #[cfg(feature = "ws")]
@@ -16,7 +16,7 @@ use crate::codec::WsJsonCodec;
 
 use crate::{codec::JsonCodec, Error, Result, TcpConfig};
 
-use super::Client;
+use super::{Client, MessageDispatcher, Subscriber};
 
 const DEFAULT_TIMEOUT: u64 = 3000; // 3s
 
@@ -171,8 +171,8 @@ impl ClientBuilder {
         let client = Arc::new(Client {
             timeout: self.timeout,
             conn,
-            chans: Mutex::new(HashMap::new()),
-            subscriptions: Mutex::new(HashMap::new()),
+            message_dispatcher: MessageDispatcher::new(),
+            subscriber: Subscriber::new(),
             task_group: TaskGroup::new(),
         });
         client.start_background_receiving();
diff --git a/jsonrpc/src/client/message_dispatcher.rs b/jsonrpc/src/client/message_dispatcher.rs
new file mode 100644
index 0000000..a803f6e
--- /dev/null
+++ b/jsonrpc/src/client/message_dispatcher.rs
@@ -0,0 +1,54 @@
+use std::collections::HashMap;
+
+use async_channel::{Receiver, Sender};
+
+use karyon_core::async_runtime::lock::Mutex;
+
+use crate::{message, Error, Result};
+
+use super::RequestID;
+
+const CHANNEL_CAP: usize = 10;
+
+/// Manages client requests
+pub(super) struct MessageDispatcher {
+    chans: Mutex<HashMap<RequestID, Sender<message::Response>>>,
+}
+
+impl MessageDispatcher {
+    /// Creates a new MessageDispatcher
+    pub(super) fn new() -> Self {
+        Self {
+            chans: Mutex::new(HashMap::new()),
+        }
+    }
+
+    /// Registers a new request with a given ID and returns a Receiver channel
+    /// to wait for the response.
+    pub(super) async fn register(&self, id: RequestID) -> Receiver<message::Response> {
+        let (tx, rx) = async_channel::bounded(CHANNEL_CAP);
+        self.chans.lock().await.insert(id, tx);
+        rx
+    }
+
+    /// Unregisters the request with the provided ID
+    pub(super) async fn unregister(&self, id: &RequestID) {
+        self.chans.lock().await.remove(id);
+    }
+
+    /// Dispatches a response to the channel associated with the response's ID.
+    ///
+    /// If a channel is registered for the response's ID, the response is sent
+    /// through that channel. If no channel is found for the ID, returns an error.
+    pub(super) async fn dispatch(&self, res: message::Response) -> Result<()> {
+        if res.id.is_none() {
+            return Err(Error::InvalidMsg("Response id is none"));
+        }
+        let id: RequestID = serde_json::from_value(res.id.clone().unwrap())?;
+        let val = self.chans.lock().await.remove(&id);
+        match val {
+            Some(tx) => tx.send(res).await.map_err(Error::from),
+            None => Err(Error::InvalidMsg("Receive unknown message")),
+        }
+    }
+}
diff --git a/jsonrpc/src/client/mod.rs b/jsonrpc/src/client/mod.rs
index 3a4505c..95354d3 100644
--- a/jsonrpc/src/client/mod.rs
+++ b/jsonrpc/src/client/mod.rs
@@ -1,13 +1,13 @@
 pub mod builder;
+mod message_dispatcher;
+mod subscriber;
 
-use std::{collections::HashMap, sync::Arc, time::Duration};
-
-use log::{debug, error, warn};
+use log::{debug, error};
 use serde::{de::DeserializeOwned, Serialize};
 use serde_json::json;
+use std::{sync::Arc, time::Duration};
 
 use karyon_core::{
-    async_runtime::lock::Mutex,
     async_util::{timeout, TaskGroup, TaskResult},
     util::random_32,
 };
@@ -18,21 +18,19 @@ use crate::{
     Error, Result,
 };
 
-const CHANNEL_CAP: usize = 10;
+use message_dispatcher::MessageDispatcher;
+use subscriber::Subscriber;
+pub use subscriber::Subscription;
 
-/// Type alias for a subscription to receive notifications.
-///
-/// The receiver channel is returned by the `subscribe` method to receive
-/// notifications from the server.
-pub type Subscription = async_channel::Receiver<serde_json::Value>;
+type RequestID = u32;
 
 /// Represents an RPC client
 pub struct Client {
     conn: Conn<serde_json::Value>,
     timeout: Option<u64>,
-    chans: Mutex<HashMap<u32, async_channel::Sender<message::Response>>>,
-    subscriptions: Mutex<HashMap<SubscriptionID, async_channel::Sender<serde_json::Value>>>,
+    message_dispatcher: MessageDispatcher,
     task_group: TaskGroup,
+    subscriber: Subscriber,
 }
 
 impl Client {
@@ -67,10 +65,9 @@ impl Client {
             None => return Err(Error::InvalidMsg("Invalid subscription id")),
         };
 
-        let (ch_tx, ch_rx) = async_channel::bounded(CHANNEL_CAP);
-        self.subscriptions.lock().await.insert(sub_id, ch_tx);
+        let rx = self.subscriber.subscribe(sub_id).await;
 
-        Ok((sub_id, ch_rx))
+        Ok((sub_id, rx))
     }
 
     /// Unsubscribes from the provided method, waits for the response, and returns the result.
@@ -79,7 +76,7 @@ impl Client {
     /// and subscription ID. It waits for the response to confirm the unsubscription.
     pub async fn unsubscribe(&self, method: &str, sub_id: SubscriptionID) -> Result<()> {
         let _ = self.send_request(method, sub_id).await?;
-        self.subscriptions.lock().await.remove(&sub_id);
+        self.subscriber.unsubscribe(&sub_id).await;
         Ok(())
     }
 
@@ -88,7 +85,7 @@ impl Client {
         method: &str,
         params: T,
     ) -> Result<message::Response> {
-        let id = random_32();
+        let id: RequestID = random_32();
         let request = message::Request {
             jsonrpc: message::JSONRPC_VERSION.to_string(),
             id: json!(id),
@@ -98,16 +95,24 @@ impl Client {
 
         let req_json = serde_json::to_value(&request)?;
 
+        // Send the json request
         self.conn.send(req_json).await?;
 
-        let (tx, rx) = async_channel::bounded(CHANNEL_CAP);
-        self.chans.lock().await.insert(id, tx);
+        // Register a new request
+        let rx = self.message_dispatcher.register(id).await;
+
+        // Wait for the message dispatcher to send the response
+        let result = match self.timeout {
+            Some(t) => timeout(Duration::from_millis(t), rx.recv()).await?,
+            None => rx.recv().await,
+        };
 
-        let response = match self.wait_for_response(rx).await {
+        let response = match result {
             Ok(r) => r,
             Err(err) => {
-                self.chans.lock().await.remove(&id);
-                return Err(err);
+                // Unregister the request if an error occurs
+                self.message_dispatcher.unregister(&id).await;
+                return Err(err.into());
             }
         };
 
@@ -115,6 +120,8 @@ impl Client {
             return Err(Error::SubscribeError(error.code, error.message));
         }
 
+        // It should be OK to unwrap here, as the message dispatcher checks
+        // for the response id.
         if *response.id.as_ref().unwrap() != request.id {
             return Err(Error::InvalidMsg("Invalid response id"));
         }
@@ -123,28 +130,17 @@ impl Client {
         Ok(response)
     }
 
-    async fn wait_for_response(
-        &self,
-        rx: async_channel::Receiver<message::Response>,
-    ) -> Result<message::Response> {
-        match self.timeout {
-            Some(t) => timeout(Duration::from_millis(t), rx.recv())
-                .await?
-                .map_err(Error::from),
-            None => rx.recv().await.map_err(Error::from),
-        }
-    }
-
     fn start_background_receiving(self: &Arc<Self>) {
         let selfc = self.clone();
-        let on_failure = |result: TaskResult<Result<()>>| async move {
+        let on_complete = |result: TaskResult<Result<()>>| async move {
             if let TaskResult::Completed(Err(err)) = result {
                 error!("background receiving stopped: {err}");
             }
-            // drop all subscription channels
-            selfc.subscriptions.lock().await.clear();
+            // Drop all subscription
+            selfc.subscriber.drop_all().await;
         };
         let selfc = self.clone();
+        // Spawn a new task for listing to new coming messages.
         self.task_group.spawn(
             async move {
                 loop {
@@ -157,48 +153,23 @@ impl Client {
                     }
                 }
             },
-            on_failure,
+            on_complete,
         );
     }
 
     async fn handle_msg(&self, msg: serde_json::Value) -> Result<()> {
+        // Check if the received message is of type Response
         if let Ok(res) = serde_json::from_value::<message::Response>(msg.clone()) {
             debug!("<-- {res}");
-            if res.id.is_none() {
-                return Err(Error::InvalidMsg("Response id is none"));
-            }
-
-            let id: u32 = serde_json::from_value(res.id.clone().unwrap())?;
-            match self.chans.lock().await.remove(&id) {
-                Some(tx) => tx.send(res).await?,
-                None => return Err(Error::InvalidMsg("Receive unkown message")),
-            }
-
+            self.message_dispatcher.dispatch(res).await?;
             return Ok(());
         }
 
+        // Check if the received message is of type Notification
         if let Ok(nt) = serde_json::from_value::<message::Notification>(msg.clone()) {
             debug!("<-- {nt}");
-            let sub_result: message::NotificationResult = match nt.params {
-                Some(ref p) => serde_json::from_value(p.clone())?,
-                None => return Err(Error::InvalidMsg("Invalid notification msg")),
-            };
-
-            match self
-                .subscriptions
-                .lock()
-                .await
-                .get(&sub_result.subscription)
-            {
-                Some(s) => {
-                    s.send(sub_result.result.unwrap_or(json!(""))).await?;
-                    return Ok(());
-                }
-                None => {
-                    warn!("Receive unknown notification {}", sub_result.subscription);
-                    return Ok(());
-                }
-            }
+            self.subscriber.notify(nt).await?;
+            return Ok(());
         }
 
         error!("Receive unexpected msg: {msg}");
diff --git a/jsonrpc/src/client/subscriber.rs b/jsonrpc/src/client/subscriber.rs
new file mode 100644
index 0000000..d47cc2a
--- /dev/null
+++ b/jsonrpc/src/client/subscriber.rs
@@ -0,0 +1,64 @@
+use std::collections::HashMap;
+
+use async_channel::{Receiver, Sender};
+use log::warn;
+use serde_json::json;
+
+use karyon_core::async_runtime::lock::Mutex;
+
+use crate::{
+    message::{Notification, NotificationResult, SubscriptionID},
+    Error, Result,
+};
+
+const CHANNEL_CAP: usize = 10;
+
+/// Manages subscriptions for the client.
+pub(super) struct Subscriber {
+    subs: Mutex<HashMap<SubscriptionID, Sender<serde_json::Value>>>,
+}
+
+/// Type alias for a subscription to receive notifications.
+///
+/// The receiver channel is returned by the `subscribe`
+pub type Subscription = Receiver<serde_json::Value>;
+
+impl Subscriber {
+    pub(super) fn new() -> Self {
+        Self {
+            subs: Mutex::new(HashMap::new()),
+        }
+    }
+
+    pub(super) async fn subscribe(&self, id: SubscriptionID) -> Receiver<serde_json::Value> {
+        let (ch_tx, ch_rx) = async_channel::bounded(CHANNEL_CAP);
+        self.subs.lock().await.insert(id, ch_tx);
+        ch_rx
+    }
+
+    pub(super) async fn drop_all(&self) {
+        self.subs.lock().await.clear();
+    }
+
+    /// Unsubscribe
+    pub(super) async fn unsubscribe(&self, id: &SubscriptionID) {
+        self.subs.lock().await.remove(id);
+    }
+
+    pub(super) async fn notify(&self, nt: Notification) -> Result<()> {
+        let nt_res: NotificationResult = match nt.params {
+            Some(ref p) => serde_json::from_value(p.clone())?,
+            None => return Err(Error::InvalidMsg("Invalid notification msg")),
+        };
+        match self.subs.lock().await.get(&nt_res.subscription) {
+            Some(s) => {
+                s.send(nt_res.result.unwrap_or(json!(""))).await?;
+                Ok(())
+            }
+            None => {
+                warn!("Receive unknown notification {}", nt_res.subscription);
+                Ok(())
+            }
+        }
+    }
+}