Fix timeline staleness

Signed-off-by: Daniel D’Aquino <daniel@daquino.me>

damus/ContentView.swift

@@ -475,7 +475,7 @@ struct ContentView: View {
             }
         }
         .onReceive(handle_notify(.disconnect_relays)) { () in
-            damus_state.nostrNetwork.disconnect()
+            damus_state.nostrNetwork.disconnectRelays()
         }
         .onReceive(NotificationCenter.default.publisher(for: UIApplication.willEnterForegroundNotification)) { obj in
             print("txn: 📙 DAMUS ACTIVE NOTIFY")
@@ -523,7 +523,7 @@ struct ContentView: View {
                 damusClosingTask = Task { @MainActor in
                     Log.debug("App background signal handling: App being backgrounded", for: .app_lifecycle)
                     let startTime = CFAbsoluteTimeGetCurrent()
-                    await damus_state.nostrNetwork.close()  // Close ndb streaming tasks before closing ndb to avoid memory errors
+                    await damus_state.nostrNetwork.handleAppBackgroundRequest()  // Close ndb streaming tasks before closing ndb to avoid memory errors
                     Log.debug("App background signal handling: Nostr network closed after %.2f seconds", for: .app_lifecycle, CFAbsoluteTimeGetCurrent() - startTime)
                     damus_state.ndb.close()
                     Log.debug("App background signal handling: Ndb closed after %.2f seconds", for: .app_lifecycle, CFAbsoluteTimeGetCurrent() - startTime)
@@ -537,7 +537,8 @@ struct ContentView: View {
                 print("txn: 📙 DAMUS ACTIVE")
                 Task {
                     await damusClosingTask?.value  // Wait for the closing task to finish before reopening things, to avoid race conditions
-                    damus_state.nostrNetwork.connect()
+                    damusClosingTask = nil
+                    // Pinging the network will automatically reconnect any dead websocket connections
                     damus_state.nostrNetwork.ping()
                 }
             @unknown default:

damus/Core/Networking/NostrNetworkManager/NostrNetworkManager.swift

@@ -51,15 +51,18 @@ class NostrNetworkManager {
     
     /// Connects the app to the Nostr network
     func connect() {
-        self.userRelayList.connect()
-        self.pool.open = true
+        self.userRelayList.connect()    // Will load the user's list, apply it, and get RelayPool to connect to it.
         Task { await self.profilesManager.load() }
     }
     
-    func disconnect() {
+    func disconnectRelays() {
         self.pool.disconnect()
     }
     
+    func handleAppBackgroundRequest() async {
+        await self.reader.cancelAllTasks()
+    }
+    
     func close() async {
         await withTaskGroup { group in
             // Spawn each cancellation task in parallel for faster execution speed
@@ -69,9 +72,9 @@ class NostrNetworkManager {
             group.addTask {
                 await self.profilesManager.stop()
             }
-            pool.close()
             // But await on each one to prevent race conditions
             for await value in group { continue }
+            pool.close()
         }
     }
     

damus/Core/Networking/NostrNetworkManager/SubscriptionManager.swift

@@ -254,13 +254,13 @@ extension NostrNetworkManager {
                 }
                 
                 Task {
+                    // Add the ndb streaming task to the task manager so that it can be cancelled when the app is backgrounded
                     let ndbStreamTaskId = await self.taskManager.add(task: ndbStreamTask)
-                    let streamTaskId = await self.taskManager.add(task: streamTask)
                     
                     continuation.onTermination = { @Sendable _ in
                         Task {
                             await self.taskManager.cancelAndCleanUp(taskId: ndbStreamTaskId)
-                            await self.taskManager.cancelAndCleanUp(taskId: streamTaskId)
+                            streamTask.cancel()
                         }
                     }
                 }

damus/Core/Networking/NostrNetworkManager/UserRelayListManager.swift

@@ -237,8 +237,13 @@ extension NostrNetworkManager {
                 changed = true
             }
             
-            if changed {
+            // Always tell RelayPool to connect whether or not we are already connected.
+            // This is because:
+            // 1. Internally it won't redo the connection because of internal checks
+            // 2. Even if the relay list has not changed, relays may have been disconnected from app lifecycle or other events
             pool.connect()
+
+            if changed {
                 notify(.relays_changed)
             }
         }

damus/Core/Nostr/RelayPool.swift

@@ -10,7 +10,7 @@ import Network
 
 struct RelayHandler {
     let sub_id: String
-    let callback: (RelayURL, NostrConnectionEvent) -> ()
+    var callback: (RelayURL, NostrConnectionEvent) -> ()
 }
 
 struct QueuedRequest {
@@ -95,7 +95,7 @@ class RelayPool {
 
     func remove_handler(sub_id: String) {
         self.handlers = handlers.filter { $0.sub_id != sub_id }
-        print("removing \(sub_id) handler, current: \(handlers.count)")
+        Log.debug("Removing %s handler, current: %d", for: .networking, sub_id, handlers.count)
     }
     
     func ping() {
@@ -112,16 +112,17 @@ class RelayPool {
             try? await Task.sleep(for: .seconds(1))
         }
         Log.debug("%s: Subscription pool cleared", for: .networking, sub_id)
-        for handler in handlers {
-            // don't add duplicate handlers
+        handlers = handlers.filter({ handler in
             if handler.sub_id == sub_id {
-                assertionFailure("Duplicate handlers are not allowed. Proper error handling for this has not been built yet.")
-                Log.error("Duplicate handlers are not allowed. Error handling for this has not been built yet.", for: .networking)
-                return
+                Log.error("Duplicate handler detected for the same subscription ID. Overriding.", for: .networking)
+                return false
             }
+            else {
+                return true
             }
+        })
         self.handlers.append(RelayHandler(sub_id: sub_id, callback: handler))
-        print("registering \(sub_id) handler, current: \(self.handlers.count)")
+        Log.debug("Registering %s handler, current: %d", for: .networking, sub_id, self.handlers.count)
     }
 
     func remove_relay(_ relay_id: RelayURL) {
@@ -194,14 +195,17 @@ class RelayPool {
     }
 
     func connect(to: [RelayURL]? = nil) {
-        open = true
         let relays = to.map{ get_relays($0) } ?? self.relays
         for relay in relays {
             relay.connection.connect()
         }
+        // Mark as open last, to prevent other classes from pulling data before the relays are actually connected
+        open = true
     }
 
     func disconnect(to: [RelayURL]? = nil) {
+        // Mark as closed first, to prevent other classes from pulling data while the relays are being disconnected
+        open = false
         let relays = to.map{ get_relays($0) } ?? self.relays
         for relay in relays {
             relay.connection.disconnect()
@@ -218,9 +222,11 @@ class RelayPool {
     func subscribe(sub_id: String, filters: [NostrFilter], handler: @escaping (RelayURL, NostrConnectionEvent) -> (), to: [RelayURL]? = nil) {
         Task {
             await register_handler(sub_id: sub_id, handler: handler)
+            
             // When the caller specifies no relays, it is implied that the user wants to use the ones in the user relay list. Skip ephemeral relays in that case.
             // When the caller specifies specific relays, do not skip ephemeral relays to respect the exact list given by the caller.
             let shouldSkipEphemeralRelays = to == nil ? true : false
+            
             send(.subscribe(.init(filters: filters, sub_id: sub_id)), to: to, skip_ephemeral: shouldSkipEphemeralRelays)
         }
     }
@@ -299,6 +305,7 @@ class RelayPool {
     func subscribe_to(sub_id: String, filters: [NostrFilter], to: [RelayURL]?, handler: @escaping (RelayURL, NostrConnectionEvent) -> ()) {
         Task {
             await register_handler(sub_id: sub_id, handler: handler)
+            
             send(.subscribe(.init(filters: filters, sub_id: sub_id)), to: to)
         }
     }