refinements to RelayConnection and RelayPool

damus/Models/EventsModel.swift

@@ -31,9 +31,9 @@ class EventsModel: ObservableObject {
     }
     
     func subscribe() {
-        state.pool.subscribe(sub_id: sub_id,
+        state.pool.subscribe_to(sub_id: sub_id,
-                             filters: [get_filter()],
+                                filters: [get_filter()],
-                             handler: handle_nostr_event)
+                                handler: handle_nostr_event)
     }
     
     func unsubscribe() {

damus/Models/FollowersModel.swift

@@ -40,7 +40,7 @@ class FollowersModel: ObservableObject {
         let filter = get_filter()
         let filters = [filter]
         print_filters(relay_id: "following", filters: [filters])
-        self.damus_state.pool.subscribe(sub_id: sub_id, filters: filters, handler: handle_event)
+        self.damus_state.pool.subscribe_to(sub_id: sub_id, filters: filters, handler: handle_event)
     }
     
     func unsubscribe() {

damus/Models/FollowingModel.swift

@@ -41,7 +41,7 @@ class FollowingModel {
         }
         let filters = [filter]
         print_filters(relay_id: "following", filters: [filters])
-        self.damus_state.pool.subscribe(sub_id: sub_id, filters: filters, handler: handle_event)
+        self.damus_state.pool.subscribe_to(sub_id: sub_id, filters: filters, handler: handle_event)
     }
     
     func unsubscribe() {

damus/Models/ProfileModel.swift

@@ -83,8 +83,8 @@ class ProfileModel: ObservableObject, Equatable {
         
         print("subscribing to profile \(pubkey) with sub_id \(sub_id)")
         print_filters(relay_id: "profile", filters: [[text_filter], [profile_filter]])
-        damus.pool.subscribe(sub_id: sub_id, filters: [text_filter], handler: handle_event)
+        damus.pool.subscribe_to(sub_id: sub_id, filters: [text_filter], handler: handle_event)
-        damus.pool.subscribe(sub_id: prof_subid, filters: [profile_filter], handler: handle_event)
+        damus.pool.subscribe_to(sub_id: prof_subid, filters: [profile_filter], handler: handle_event)
     }
     
     func handle_profile_contact_event(_ ev: NostrEvent) {

damus/Models/SearchHomeModel.swift

@@ -38,7 +38,7 @@ class SearchHomeModel: ObservableObject {
     func subscribe() {
         loading = true
         let to_relays = determine_to_relays(pool: damus_state.pool, filters: damus_state.relay_filters)
-        damus_state.pool.subscribe(sub_id: base_subid, filters: [get_base_filter()], handler: handle_event, to: to_relays)
+        damus_state.pool.subscribe_to(sub_id: base_subid, filters: [get_base_filter()], to: to_relays, handler: handle_event)
     }
 
     func unsubscribe(to: String? = nil) {

damus/Models/ZapsModel.swift

@@ -29,7 +29,7 @@ class ZapsModel: ObservableObject {
         case .note(let note_target):
             filter.referenced_ids = [note_target.note_id]
         }
-        state.pool.subscribe(sub_id: zaps_subid, filters: [filter], handler: handle_event)
+        state.pool.subscribe_to(sub_id: zaps_subid, filters: [filter], handler: handle_event)
     }
     
     func unsubscribe() {

damus/Nostr/RelayConnection.swift

@@ -14,9 +14,15 @@ enum NostrConnectionEvent {
 }
 
 final class RelayConnection: WebSocketDelegate {
-    private(set) var isConnected = false
+    enum State {
-    private(set) var isConnecting = false
+        case notConnected
-    private(set) var isReconnecting = false
+        case connecting
+        case reconnecting
+        case connected
+        case failed
+    }
+    
+    private(set) var state: State = .notConnected
     
     private(set) var last_connection_attempt: TimeInterval = 0
     private lazy var socket = {
@@ -25,38 +31,36 @@ final class RelayConnection: WebSocketDelegate {
         socket.delegate = self
         return socket
     }()
-    private var handleEvent: (NostrConnectionEvent) -> ()
+    private let eventHandler: (NostrConnectionEvent) -> ()
     let url: URL
-
+    
-    init(url: URL, handleEvent: @escaping (NostrConnectionEvent) -> ()) {
+    init(url: URL, eventHandler: @escaping (NostrConnectionEvent) -> ()) {
         self.url = url
-        self.handleEvent = handleEvent
+        self.eventHandler = eventHandler
     }
     
     func reconnect() {
-        if isConnected {
+        if state == .connected {
-            isReconnecting = true
+            state = .reconnecting
             disconnect()
         } else {
             // we're already disconnected, so just connect
-            connect(force: true)
+            connect()
         }
     }
     
     func connect(force: Bool = false) {
-        if !force && (isConnected || isConnecting) {
+        if !force && (state == .connected || state == .connecting) {
             return
         }
         
-        isConnecting = true
+        state = .connecting
         last_connection_attempt = Date().timeIntervalSince1970
         socket.connect()
     }
 
     func disconnect() {
         socket.disconnect()
-        isConnected = false
-        isConnecting = false
     }
 
     func send(_ req: NostrRequest) {
@@ -68,51 +72,52 @@ final class RelayConnection: WebSocketDelegate {
         socket.write(string: req)
     }
     
+    private func decodeEvent(_ txt: String) throws -> NostrConnectionEvent {
+        if let ev = decode_nostr_event(txt: txt) {
+            return .nostr_event(ev)
+        } else {
+            throw DecodingError.dataCorrupted(.init(codingPath: [], debugDescription: "decoding event failed"))
+        }
+    }
+    
+    @MainActor
+    private func handleEvent(_ event: NostrConnectionEvent) async {
+        eventHandler(event)
+    }
+    
     // MARK: - WebSocketDelegate
     
     func didReceive(event: WebSocketEvent, client: WebSocket) {
         switch event {
         case .connected:
-            self.isConnected = true
+            state = .connected
-            self.isConnecting = false
 
         case .disconnected:
-            self.isConnecting = false
+            if state == .reconnecting {
-            self.isConnected = false
+                connect()
-            if self.isReconnecting {
+            } else {
-                self.isReconnecting = false
+                state = .notConnected
-                self.connect()
             }
 
         case .cancelled, .error:
-            self.isConnecting = false
+            state = .failed
-            self.isConnected = false
 
         case .text(let txt):
-            if txt.count > 2000 {
+            Task(priority: .userInitiated) {
-                DispatchQueue.global(qos: .default).async {
+                do {
-                    if let ev = decode_nostr_event(txt: txt) {
+                    let event = try decodeEvent(txt)
-                        DispatchQueue.main.async {
+                    await handleEvent(event)
-                            self.handleEvent(.nostr_event(ev))
+                } catch {
-                        }
+                    print("decode failed for \(txt): \(error)")
-                        return
+                    // TODO: trigger event error
-                    }
-                }
-            } else {
-                if let ev = decode_nostr_event(txt: txt) {
-                    handleEvent(.nostr_event(ev))
-                    return
                 }
             }
 
-            print("decode failed for \(txt)")
-            // TODO: trigger event error
-
         default:
             break
         }
 
-        handleEvent(.ws_event(event))
+        eventHandler(.ws_event(event))
     }
 }
 

damus/Nostr/RelayPool.swift

@@ -7,22 +7,6 @@
 
 import Foundation
 
-struct SubscriptionId: Identifiable, CustomStringConvertible {
-    let id: String
-
-    var description: String {
-        id
-    }
-}
-
-struct RelayId: Identifiable, CustomStringConvertible {
-    let id: String
-
-    var description: String {
-        id
-    }
-}
-
 struct RelayHandler {
     let sub_id: String
     let callback: (String, NostrConnectionEvent) -> ()
@@ -33,22 +17,21 @@ struct QueuedRequest {
     let relay: String
 }
 
-struct NostrRequestId: Equatable, Hashable {
+final class RelayPool {
-    let relay: String?
+    private enum Constants {
-    let sub_id: String
+        /// Used for an exponential backoff algorithm when retrying stale connections
-}
+        /// Each retry attempt will be delayed by raising this base delay to an exponent
-
+        /// equal to the number of previous retries.
-class RelayPool {
+        static let base_reconnect_delay: TimeInterval = 2
-    /// Used for an exponential backoff algorithm when retrying stale connections
+        static let max_queued_requests = 10
-    /// Each retry attempt will be delayed by raising this base delay to an exponent
+        static let max_retry_attempts = 3
-    /// equal to the number of previous retries.
+    }
-    private static let base_reconnect_delay: TimeInterval = 2
     
-    var relays: [Relay] = []
+    private(set) var relays: [Relay] = []
-    var handlers: [RelayHandler] = []
+    private var handlers: [RelayHandler] = []
-    var request_queue: [QueuedRequest] = []
+    private var request_queue: [QueuedRequest] = []
-    var seen: Set<String> = Set()
+    private var seen: Set<String> = Set()
-    var counts: [String: UInt64] = [:]
+    private var counts: [String: UInt64] = [:]
     private var retry_attempts_per_relay: [URL: Int] = [:]
 
     var descriptors: [RelayDescriptor] {
@@ -56,37 +39,28 @@ class RelayPool {
     }
     
     var num_connecting: Int {
-        return relays.reduce(0) { n, r in n + (r.connection.isConnecting ? 1 : 0) }
+        relays.reduce(0) { n, r in n + (r.connection.state == .connecting ? 1 : 0) }
     }
 
-    func remove_handler(sub_id: String) {
+    private func remove_handler(sub_id: String) {
         self.handlers = handlers.filter { $0.sub_id != sub_id }
         print("removing \(sub_id) handler, current: \(handlers.count)")
     }
 
     func register_handler(sub_id: String, handler: @escaping (String, NostrConnectionEvent) -> ()) {
-        for handler in handlers {
+        guard !handlers.contains(where: { $0.sub_id == sub_id }) else {
-            // don't add duplicate handlers
+            return  // don't add duplicate handlers
-            if handler.sub_id == sub_id {
-                return
-            }
         }
-        self.handlers.append(RelayHandler(sub_id: sub_id, callback: handler))
+        
+        handlers.append(RelayHandler(sub_id: sub_id, callback: handler))
         print("registering \(sub_id) handler, current: \(self.handlers.count)")
     }
     
     func remove_relay(_ relay_id: String) {
-        var i: Int = 0
+        disconnect(from: [relay_id])
         
-        self.disconnect(to: [relay_id])
+        if let index = relays.firstIndex(where: { $0.id == relay_id }) {
-        
+            relays.remove(at: index)
-        for relay in relays {
-            if relay.id == relay_id {
-                relays.remove(at: i)
-                break
-            }
-            
-            i += 1
         }
     }
     
@@ -105,38 +79,51 @@ class RelayPool {
     
     /// This is used to retry dead connections
     func connect_to_disconnected() {
-        for relay in relays where !relay.is_broken && !relay.connection.isConnected {
+        for relay in relays where !relay.is_broken && relay.connection.state != .connected {
             let c = relay.connection
             
-            let is_connecting = c.isReconnecting || c.isConnecting
+            let is_connecting = c.state == .reconnecting || c.state == .connecting
             
             let retry_attempts = retry_attempts_per_relay[c.url] ?? 0
-            let delay = pow(RelayPool.base_reconnect_delay, TimeInterval(retry_attempts_per_relay[c.url] ?? 0))
+            
+            let delay = pow(Constants.base_reconnect_delay, TimeInterval(retry_attempts + 1))   // the + 1 helps us avoid a 1-second delay for the first retry
             if is_connecting && (Date.now.timeIntervalSince1970 - c.last_connection_attempt) > delay {
-                print("stale connection detected (\(relay.descriptor.url.absoluteString)). retrying after \(delay) seconds...")
+                if retry_attempts > Constants.max_retry_attempts {
-                relay.connection.connect(force: true)
+                    if c.state != .notConnected {
-                retry_attempts_per_relay[c.url] = retry_attempts + 1
+                        c.disconnect()
+                        print("exceeded max connection attempts with \(relay.descriptor.url.absoluteString)")
+                        relay.mark_broken()
+                    }
+                    continue
+                } else {
+                    print("stale connection detected (\(relay.descriptor.url.absoluteString)). retrying after \(delay) seconds...")
+                    c.connect(force: true)
+                    retry_attempts_per_relay[c.url] = retry_attempts + 1
+                }
             } else if is_connecting {
                 continue
             } else {
-                relay.connection.reconnect()
+                c.reconnect()
             }
-            
         }
     }
     
-    func reconnect(to: [String]? = nil) {
+    func reconnect(to relay_ids: [String]? = nil) {
-        let relays = to.map{ get_relays($0) } ?? self.relays
+        let relays: [Relay]
-        for relay in relays {
+        if let relay_ids {
+            relays = get_relays(relay_ids)
+        } else {
+            relays = self.relays
+        }
+        
+        for relay in relays where !relay.is_broken {
             // don't try to reconnect to broken relays
             relay.connection.reconnect()
         }
     }
     
     func mark_broken(_ relay_id: String) {
-        for relay in relays {
+        relays.first(where: { $0.id == relay_id })?.mark_broken()
-            relay.mark_broken()
-        }
     }
 
     func connect(to: [String]? = nil) {
@@ -146,8 +133,8 @@ class RelayPool {
         }
     }
 
-    func disconnect(to: [String]? = nil) {
+    private func disconnect(from: [String]? = nil) {
-        let relays = to.map{ get_relays($0) } ?? self.relays
+        let relays = from.map{ get_relays($0) } ?? self.relays
         for relay in relays {
             relay.connection.disconnect()
         }
@@ -155,35 +142,23 @@ class RelayPool {
     
     func unsubscribe(sub_id: String, to: [String]? = nil) {
         if to == nil {
-            self.remove_handler(sub_id: sub_id)
+            remove_handler(sub_id: sub_id)
         }
-        self.send(.unsubscribe(sub_id), to: to)
+        send(.unsubscribe(sub_id), to: to)
     }
     
-    func subscribe(sub_id: String, filters: [NostrFilter], handler: @escaping (String, NostrConnectionEvent) -> (), to: [String]? = nil) {
+    func subscribe_to(sub_id: String, filters: [NostrFilter], to: [String]? = nil, handler: @escaping (String, NostrConnectionEvent) -> ()) {
         register_handler(sub_id: sub_id, handler: handler)
         send(.subscribe(.init(filters: filters, sub_id: sub_id)), to: to)
     }
     
-    func subscribe_to(sub_id: String, filters: [NostrFilter], to: [String]?, handler: @escaping (String, NostrConnectionEvent) -> ()) {
+    private func count_queued(relay: String) -> Int {
-        register_handler(sub_id: sub_id, handler: handler)
+        request_queue.filter({ $0.relay == relay }).count
-        send(.subscribe(.init(filters: filters, sub_id: sub_id)), to: to)
-    }
-    
-    func count_queued(relay: String) -> Int {
-        var c = 0
-        for request in request_queue {
-            if request.relay == relay {
-                c += 1
-            }
-        }
-        
-        return c
     }
     
     func queue_req(r: NostrRequest, relay: String) {
         let count = count_queued(relay: relay)
-        guard count <= 10 else {
+        guard count <= Constants.max_queued_requests else {
             print("can't queue, too many queued events for \(relay)")
             return
         }
@@ -193,10 +168,10 @@ class RelayPool {
     }
     
     func send(_ req: NostrRequest, to: [String]? = nil) {
-        let relays = to.map{ get_relays($0) } ?? self.relays
+        let relays = to.map { get_relays($0) } ?? self.relays
-
+        
         for relay in relays {
-            guard relay.connection.isConnected else {
+            guard relay.connection.state == .connected else {
                 queue_req(r: req, relay: relay.id)
                 continue
             }
@@ -216,17 +191,14 @@ class RelayPool {
     func record_last_pong(relay_id: String, event: NostrConnectionEvent) {
         if case .ws_event(let ws_event) = event {
             if case .pong = ws_event {
-                for relay in relays {
+                if let relay = relays.first(where: { $0.id == relay_id }) {
-                    if relay.id == relay_id {
+                    relay.last_pong = UInt32(Date.now.timeIntervalSince1970)
-                        relay.last_pong = UInt32(Date.now.timeIntervalSince1970)
-                        return
-                    }
                 }
             }
         }
     }
     
-    func run_queue(_ relay_id: String) {
+    private func run_queue(_ relay_id: String) {
         self.request_queue = request_queue.reduce(into: Array<QueuedRequest>()) { (q, req) in
             guard req.relay == relay_id else {
                 q.append(req)
@@ -238,23 +210,20 @@ class RelayPool {
         }
     }
     
-    func record_seen(relay_id: String, event: NostrConnectionEvent) {
+    private func record_seen(relay_id: String, event: NostrConnectionEvent) {
         if case .nostr_event(let ev) = event {
             if case .event(_, let nev) = ev {
                 let k = relay_id + nev.id
                 if !seen.contains(k) {
                     seen.insert(k)
-                    if counts[relay_id] == nil {
+                    let prev_count = counts[relay_id] ?? 0
-                        counts[relay_id] = 1
+                    counts[relay_id] = prev_count + 1
-                    } else {
-                        counts[relay_id] = (counts[relay_id] ?? 0) + 1
-                    }
                 }
             }
         }
     }
     
-    func handle_event(relay_id: String, event: NostrConnectionEvent) {
+    private func handle_event(relay_id: String, event: NostrConnectionEvent) {
         record_last_pong(relay_id: relay_id, event: event)
         record_seen(relay_id: relay_id, event: event)
         
@@ -276,5 +245,3 @@ func add_rw_relay(_ pool: RelayPool, _ url: String) {
     let url_ = URL(string: url)!
     try? pool.add_relay(url_, info: RelayInfo.rw)
 }
-
-

damus/Views/Relays/RelayStatus.swift

@@ -7,6 +7,16 @@
 
 import SwiftUI
 
+extension RelayConnection.State {
+    var indicatorColor: Color {
+        switch self {
+        case .connected: return .green
+        case .connecting, .reconnecting: return .yellow
+        default: return .red
+        }
+    }
+}
+
 struct RelayStatus: View {
     let pool: RelayPool
     let relay: String
@@ -16,18 +26,10 @@ struct RelayStatus: View {
     @State var conn_color: Color = .gray
     
     func update_connection_color() {
-        for relay in pool.relays {
+        guard let relay = pool.relays.first(where: { $0.id == relay }) else {
-            if relay.id == self.relay {
+            return
-                let c = relay.connection
-                if c.isConnected {
-                    conn_color = .green
-                } else if c.isConnecting || c.isReconnecting {
-                    conn_color = .yellow
-                } else {
-                    conn_color = .red
-                }
-            }
         }
+        conn_color = relay.connection.state.indicatorColor
     }
     
     var body: some View {