[Relay] Socket reconnection

Sources/WalletConnectRelay/AppStateObserving.swift

@@ -1,14 +1,23 @@
 import Foundation
-#if os(iOS)
+
+#if canImport(UIKit)
 import UIKit
+#elseif canImport(AppKit)
+import AppKit
 #endif
 
-protocol AppStateObserving {
+enum ApplicationState {
+    case background, foreground
+}
+
+protocol AppStateObserving: AnyObject {
+    var currentState: ApplicationState { get }
     var onWillEnterForeground: (() -> Void)? {get set}
     var onWillEnterBackground: (() -> Void)? {get set}
 }
 
 class AppStateObserver: AppStateObserving {
+
     @objc var onWillEnterForeground: (() -> Void)?
 
     @objc var onWillEnterBackground: (() -> Void)?
@@ -17,6 +26,16 @@ class AppStateObserver: AppStateObserving {
         subscribeNotificationCenter()
     }
 
+    var currentState: ApplicationState {
+#if canImport(UIKit)
+        let isActive = UIApplication.shared.applicationState == .active
+        return isActive ? .foreground : .background
+#elseif canImport(AppKit)
+        let isActive = NSApplication.shared.isActive
+        return isActive ? .foreground : .background
+#endif
+    }
+
     private func subscribeNotificationCenter() {
 #if os(iOS)
         NotificationCenter.default.addObserver(

Sources/WalletConnectRelay/Dispatching.swift

@@ -103,6 +103,7 @@ final class Dispatcher: NSObject, Dispatching {
         }
         socket.onDisconnect = { [unowned self] _ in
             self.socketConnectionStatusPublisherSubject.send(.disconnected)
+            self.socketConnectionHandler.handleDisconnection()
         }
     }
 }

Sources/WalletConnectRelay/NetworkMonitoring.swift

@@ -1,7 +1,7 @@
 import Foundation
 import Network
 
-protocol NetworkMonitoring {
+protocol NetworkMonitoring: AnyObject {
     var onSatisfied: (() -> Void)? {get set}
     var onUnsatisfied: (() -> Void)? {get set}
     func startMonitoring()

Sources/WalletConnectRelay/SocketConnectionHandler/AutomaticSocketConnectionHandler.swift

@@ -4,26 +4,30 @@ import UIKit
 import Foundation
 import Combine
 
-class AutomaticSocketConnectionHandler: SocketConnectionHandler {
-    enum Error: Swift.Error {
-        case manualSocketConnectionForbidden
-        case manualSocketDisconnectionForbidden
+class AutomaticSocketConnectionHandler {
+
+    enum Errors: Error {
+        case manualSocketConnectionForbidden, manualSocketDisconnectionForbidden
     }
-    private var appStateObserver: AppStateObserving
-    let socket: WebSocketConnecting
-    private var networkMonitor: NetworkMonitoring
+
+    private let socket: WebSocketConnecting
+    private let appStateObserver: AppStateObserving
+    private let networkMonitor: NetworkMonitoring
     private let backgroundTaskRegistrar: BackgroundTaskRegistering
 
     private var publishers = Set<AnyCancellable>()
 
-    init(networkMonitor: NetworkMonitoring = NetworkMonitor(),
-         socket: WebSocketConnecting,
-         appStateObserver: AppStateObserving = AppStateObserver(),
-         backgroundTaskRegistrar: BackgroundTaskRegistering = BackgroundTaskRegistrar()) {
+    init(
+        socket: WebSocketConnecting,
+        networkMonitor: NetworkMonitoring = NetworkMonitor(),
+        appStateObserver: AppStateObserving = AppStateObserver(),
+        backgroundTaskRegistrar: BackgroundTaskRegistering = BackgroundTaskRegistrar()
+    ) {
         self.appStateObserver = appStateObserver
         self.socket = socket
         self.networkMonitor = networkMonitor
         self.backgroundTaskRegistrar = backgroundTaskRegistrar
+
         setUpStateObserving()
         setUpNetworkMonitoring()
 
@@ -36,40 +40,49 @@ class AutomaticSocketConnectionHandler: SocketConnectionHandler {
         }
 
         appStateObserver.onWillEnterForeground = { [unowned self] in
-            if !socket.isConnected {
-                socket.connect()
-            }
+            reconnectIfNeeded()
         }
     }
 
     private func setUpNetworkMonitoring() {
         networkMonitor.onSatisfied = { [weak self] in
-            self?.handleNetworkSatisfied()
+            self?.reconnectIfNeeded()
         }
         networkMonitor.startMonitoring()
     }
 
-    func registerBackgroundTask() {
+    private func registerBackgroundTask() {
         backgroundTaskRegistrar.register(name: "Finish Network Tasks") { [unowned self] in
             endBackgroundTask()
         }
     }
 
-    func endBackgroundTask() {
+    private func endBackgroundTask() {
         socket.disconnect()
     }
 
+    private func reconnectIfNeeded() {
+        if !socket.isConnected {
+            socket.connect()
+        }
+    }
+}
+
+// MARK: - SocketConnectionHandler
+
+extension AutomaticSocketConnectionHandler: SocketConnectionHandler {
+
     func handleConnect() throws {
-        throw Error.manualSocketConnectionForbidden
+        throw Errors.manualSocketConnectionForbidden
     }
 
     func handleDisconnect(closeCode: URLSessionWebSocketTask.CloseCode) throws {
-        throw Error.manualSocketDisconnectionForbidden
+        throw Errors.manualSocketDisconnectionForbidden
     }
 
-    func handleNetworkSatisfied() {
-        if !socket.isConnected {
-            socket.connect()
+    func handleDisconnection() {
+        if appStateObserver.currentState == .foreground {
+            reconnectIfNeeded()
         }
     }
 }

Sources/WalletConnectRelay/SocketConnectionHandler/ManualSocketConnectionHandler.swift

@@ -14,4 +14,9 @@ class ManualSocketConnectionHandler: SocketConnectionHandler {
     func handleDisconnect(closeCode: URLSessionWebSocketTask.CloseCode) throws {
         socket.disconnect()
     }
+
+    func handleDisconnection() {
+        // No operation
+        // ManualSocketConnectionHandler does not support reconnection logic
+    }
 }

Sources/WalletConnectRelay/SocketConnectionHandler/SocketConnectionHandler.swift

@@ -3,4 +3,5 @@ import Foundation
 protocol SocketConnectionHandler {
     func handleConnect() throws
     func handleDisconnect(closeCode: URLSessionWebSocketTask.CloseCode) throws
+    func handleDisconnection()
 }

Tests/RelayerTests/AutomaticSocketConnectionHandlerTests.swift

@@ -6,25 +6,26 @@ final class AutomaticSocketConnectionHandlerTests: XCTestCase {
     var sut: AutomaticSocketConnectionHandler!
     var webSocketSession: WebSocketMock!
     var networkMonitor: NetworkMonitoringMock!
-    var appStateObserver: AppStateObserving!
+    var appStateObserver: AppStateObserverMock!
     var backgroundTaskRegistrar: BackgroundTaskRegistrarMock!
+
     override func setUp() {
         webSocketSession = WebSocketMock()
         networkMonitor = NetworkMonitoringMock()
         appStateObserver = AppStateObserverMock()
         backgroundTaskRegistrar = BackgroundTaskRegistrarMock()
         sut = AutomaticSocketConnectionHandler(
-            networkMonitor: networkMonitor,
             socket: webSocketSession,
+            networkMonitor: networkMonitor,
             appStateObserver: appStateObserver,
         backgroundTaskRegistrar: backgroundTaskRegistrar)
     }
 
     func testConnectsOnConnectionSatisfied() {
         webSocketSession.disconnect()
-        XCTAssertFalse(sut.socket.isConnected)
+        XCTAssertFalse(webSocketSession.isConnected)
         networkMonitor.onSatisfied?()
-        XCTAssertTrue(sut.socket.isConnected)
+        XCTAssertTrue(webSocketSession.isConnected)
     }
 
     func testHandleConnectThrows() {
@@ -38,7 +39,7 @@ final class AutomaticSocketConnectionHandlerTests: XCTestCase {
     func testReconnectsOnEnterForeground() {
         webSocketSession.disconnect()
         appStateObserver.onWillEnterForeground?()
-        XCTAssertTrue(sut.socket.isConnected)
+        XCTAssertTrue(webSocketSession.isConnected)
     }
 
     func testRegisterTaskOnEnterBackground() {
@@ -49,8 +50,24 @@ final class AutomaticSocketConnectionHandlerTests: XCTestCase {
 
     func testDisconnectOnEndBackgroundTask() {
         appStateObserver.onWillEnterBackground?()
-        XCTAssertTrue(sut.socket.isConnected)
+        XCTAssertTrue(webSocketSession.isConnected)
         backgroundTaskRegistrar.completion!()
-        XCTAssertFalse(sut.socket.isConnected)
+        XCTAssertFalse(webSocketSession.isConnected)
+    }
+
+    func testReconnectOnDisconnectForeground() {
+        appStateObserver.currentState = .foreground
+        XCTAssertTrue(webSocketSession.isConnected)
+        webSocketSession.disconnect()
+        sut.handleDisconnection()
+        XCTAssertTrue(webSocketSession.isConnected)
+    }
+
+    func testReconnectOnDisconnectBackground() {
+        appStateObserver.currentState = .background
+        XCTAssertTrue(webSocketSession.isConnected)
+        webSocketSession.disconnect()
+        sut.handleDisconnection()
+        XCTAssertFalse(webSocketSession.isConnected)
     }
 }

Tests/RelayerTests/Mocks/AppStateObserverMock.swift

@@ -2,6 +2,7 @@ import Foundation
 @testable import WalletConnectRelay
 
 class AppStateObserverMock: AppStateObserving {
+    var currentState: ApplicationState = .foreground
     var onWillEnterForeground: (() -> Void)?
     var onWillEnterBackground: (() -> Void)?
 }