[ws server]: parse subscription ID for unsubscription instead of hardcoding JsonValue::Null

src/ws/raw/core.rs

@@ -31,6 +31,7 @@ use crate::ws::transport::{TransportServerEvent, WsRequestId as RequestId, WsTra
 use alloc::{borrow::ToOwned as _, string::String, vec, vec::Vec};
 use core::{fmt, hash::Hash, num::NonZeroUsize};
 use hashbrown::{hash_map::Entry, HashMap};
+use std::convert::TryFrom;
 
 /// Wraps around a "raw server" and adds capabilities.
 ///
@@ -399,6 +400,22 @@ impl RawServerSubscriptionId {
 	}
 }
 
+// Try to parse a subscription ID from `Params` where we try both index 0 of an array or `subscription`
+// in a `Map`.
+impl<'a> TryFrom<Params<'a>> for RawServerSubscriptionId {
+	type Error = ();
+
+	fn try_from(params: Params) -> Result<Self, Self::Error> {
+		if let Ok(other_id) = params.get(0) {
+			Self::from_wire_message(&other_id)
+		} else if let Ok(other_id) = params.get("subscription") {
+			Self::from_wire_message(&other_id)
+		} else {
+			Err(())
+		}
+	}
+}
+
 impl<'a> ServerSubscription<'a> {
 	/// Returns the id of the subscription.
 	///

src/ws/server.rs

@@ -32,6 +32,7 @@ use futures::{channel::mpsc, future::Either, pin_mut, prelude::*};
 use parking_lot::Mutex;
 use std::{
 	collections::{HashMap, HashSet},
+	convert::TryFrom,
 	error,
 	net::SocketAddr,
 	sync::{atomic, Arc},
@@ -410,8 +411,8 @@ async fn background_task(mut server: RawServer, mut from_front: mpsc::UnboundedR
 				}
 			}
 			Either::Right(RawServerEvent::Request(request)) => {
-				log::debug!("[backend]: server received request: {:?}", request);
 				if let Some(handler) = registered_methods.get_mut(request.method()) {
+					log::debug!("[backend]: server received request: {:?}", request);
 					let params: &common::Params = request.params().into();
 					log::debug!("server called handler");
 					match handler.send((request.id(), params.clone())).now_or_never() {
@@ -421,6 +422,7 @@ async fn background_task(mut server: RawServer, mut from_front: mpsc::UnboundedR
 						}
 					}
 				} else if let Some(sub_unique_id) = subscribe_methods.get(request.method()) {
+					log::debug!("[backend]: server received subscription: {:?}", request);
 					if let Ok(sub_id) = request.into_subscription() {
 						debug_assert!(subscribed_clients.contains_key(&sub_unique_id));
 						if let Some(clients) = subscribed_clients.get_mut(&sub_unique_id) {
@@ -432,21 +434,24 @@ async fn background_task(mut server: RawServer, mut from_front: mpsc::UnboundedR
 						active_subscriptions.insert(sub_id, *sub_unique_id);
 					}
 				} else if let Some(sub_unique_id) = unsubscribe_methods.get(request.method()) {
-					if let Ok(sub_id) = RawServerSubscriptionId::from_wire_message(&JsonValue::Null) {
-						// FIXME: from request params
-						debug_assert!(subscribed_clients.contains_key(&sub_unique_id));
-						if let Some(clients) = subscribed_clients.get_mut(&sub_unique_id) {
-							// TODO: we don't actually check whether the unsubscribe comes from the right
-							//       clients, but since this the ID is randomly-generated, it should be
-							//       fine
-							if let Some(client_pos) = clients.iter().position(|c| *c == sub_id) {
-								clients.remove(client_pos);
-							}
-
-							if let Some(s_u_id) = active_subscriptions.remove(&sub_id) {
-								debug_assert_eq!(s_u_id, *sub_unique_id);
+					log::debug!("[backend]: server received unsubscription: {:?}", request);
+					match RawServerSubscriptionId::try_from(request.params()) {
+						Ok(sub_id) => {
+							debug_assert!(subscribed_clients.contains_key(&sub_unique_id));
+							if let Some(clients) = subscribed_clients.get_mut(&sub_unique_id) {
+								// TODO: we don't actually check whether the unsubscribe comes from the right
+								//       clients, but since this the ID is randomly-generated, it should be
+								//       fine
+								if let Some(client_pos) = clients.iter().position(|c| *c == sub_id) {
+									clients.remove(client_pos);
+								}
+
+								if let Some(s_u_id) = active_subscriptions.remove(&sub_id) {
+									debug_assert_eq!(s_u_id, *sub_unique_id);
+								}
 							}
 						}
+						Err(_) => log::error!("Unsubscription of method=\"{}\" failed; The subscription ID must passed as the first argument of Array or \"subscription\" name of Object, got={:?}", request.method(), request.params()),
 					}
 				} else {
 					// TODO: we assert that the request is valid because the parsing succeeded but