Singleton Network Monitor

Sources/OAuthKit/Network/NetworkMonitor.swift

@@ -11,11 +11,17 @@ import Observation
 /// An  `Observable` type that publishes network reachability information.
 @MainActor
 @Observable
-public final class NetworkMonitor {
+public final class NetworkMonitor: Sendable {
+
+    // The shared singleton network monitor.
+    public static let shared: NetworkMonitor = .init()
 
     @ObservationIgnored
     private let pathMonitor = NWPathMonitor()
 
+    /// Flag indicating if monitoring is currently active or not.
+    public private(set) var isMonitoring = false
+
     /// Returns true if the network has an available wifi interface.
     public var onWifi = false
     /// Returns true if the network has an available cellular interface.
@@ -29,10 +35,12 @@ public final class NetworkMonitor {
     }
 
     /// Initializer.
-    public init() { }
+    private init() { }
 
     /// Starts the network monitor (conforms to AsyncSequence).
     public func start() async {
+        guard !isMonitoring else { return }
+        isMonitoring.toggle()
         for await path in pathMonitor {
             handle(path: path)
         }

Sources/OAuthKit/OAuth.swift

@@ -57,7 +57,7 @@ public final class OAuth: Sendable {
     private var tasks = [Task<(), any Error>]()
 
     @ObservationIgnored
-    private let networkMonitor = NetworkMonitor()
+    private let networkMonitor: NetworkMonitor = .shared
 
     /// Configuration option determining if tokens should be auto refreshed or not.
     @ObservationIgnored

Tests/OAuthKitTests/UtilityTests.swift

@@ -153,7 +153,7 @@ struct UtilityTests {
     @MainActor
     @Test("Network Monitor")
     func whenNetworkMonitoring() async throws {
-        let monitor = NetworkMonitor()
+        let monitor: NetworkMonitor = .shared
         #expect(monitor.isOnline == false)
         withObservationTracking {
             _ = monitor.isOnline
@@ -162,8 +162,15 @@ struct UtilityTests {
                 #expect(monitor.isOnline)
             }
         }
-        Task {
+        Task { @MainActor in
             await monitor.start()
+            #expect(monitor.isMonitoring)
+        }
+        // The second call to monitor.start() should simply bail as monitoring
+        // is already happening and not toggle the internal `isMonitoring` flag.
+        Task { @MainActor in
+            await monitor.start()
+            #expect(monitor.isMonitoring)
         }
     }
 }