Add BGAppRefreshTask

aaronvargas · aaronvargas · commit 612154831b92 · 2022-03-08T18:50:19.000-08:00
diff --git a/README.md b/README.md
@@ -35,7 +35,10 @@ void main() {
     callbackDispatcher, // The top level function, aka callbackDispatcher
     isInDebugMode: true // If enabled it will post a notification whenever the task is running. Handy for debugging tasks
   );
-  Workmanager().registerOneOffTask("1", "simpleTask"); //Android only (see below)
+  Workmanager().registerOneOffTask("1", "simpleTask"); // Android and 'iOS Processing task' (see options below)
+  if (Platform.isIOS) {
+    Workmanager().registerAppRefreshTask(initialDelay: const Duration(minutes: 15), frequency: const Duration(minutes: 60)); // iOS Only
+  }
   runApp(MyApp());
 }
 ```
@@ -86,7 +89,8 @@ Refer to the example app for a successful, retrying and a failed task.
 
 # Customisation (iOS - BGTaskScheduler only)
 
-iOS supports **One off tasks** with a few basic constraints:
+iOS supports **One off tasks** with a few basic constraints 
+(Note on iOS this is for long-running Processing tasks run every 1-2 days):
 
 ```dart
 Workmanager().registerOneOffTask(
@@ -99,12 +103,19 @@ Workmanager().registerOneOffTask(
     // require external power
     requiresCharging: true,
   ),
-  inputData: ... // fully supported
+  inputData: ... // Android Only
 );
 ```
 
 Tasks registered this way will appear in the callback dispatcher using as `Workmanager.iOSBackgroundProcessingTask`.
 
+```dart
+Workmanager().registerAppRefreshTask( // iOS only
+  initialDelay: const Duration(minutes: 15), // 'Suggested' initial delay, won't start sooner than this. Default: Duration.zero 
+  frequency: const Duration(minutes: 60) // 'Suggested' frequency to run after initial execution. If Duration.zero, will not repeat execution. Defalut: Duration.zero 
+);
+```
+
 For more information see the [BGTaskScheduler documentation](https://developer.apple.com/documentation/backgroundtasks).
 
 # Customisation (Android)
diff --git a/ios/Classes/SwiftWorkmanagerPlugin.swift b/ios/Classes/SwiftWorkmanagerPlugin.swift
@@ -14,7 +14,9 @@ public class SwiftWorkmanagerPlugin: FlutterPluginAppLifeCycleDelegate {
     static let identifier = "be.tramckrijte.workmanager"
 
     static let defaultBGProcessingTaskIdentifier = "workmanager.background.task"
-
+    static let defaultBGAppRefreshTaskIdentifier = "workmanager.background.refresh.task"
+    var bgRefreshTaskFrequency = 0.0
+    
     private static var flutterPluginRegistrantCallback: FlutterPluginRegistrantCallback?
 
     private struct ForegroundMethodChannel {
@@ -36,6 +38,15 @@ public class SwiftWorkmanagerPlugin: FlutterPluginAppLifeCycleDelegate {
                     case requiresCharging
                 }
             }
+
+            struct RegisterAppRefreshTask {
+                static let name = "\(RegisterAppRefreshTask.self)".lowercasingFirst
+                enum Arguments: String {
+                    case initialDelaySeconds
+                    case refreshFrequencySeconds
+                }
+            }
+
             struct CancelAllTasks {
                 static let name = "\(CancelAllTasks.self)".lowercasingFirst
                 enum Arguments: String {
@@ -77,6 +88,51 @@ public class SwiftWorkmanagerPlugin: FlutterPluginAppLifeCycleDelegate {
         operationQueue.addOperation(operation)
     }
 
+    @available(iOS 13.0, *)
+    private func scheduleAppRefresh() {
+        let request = BGAppRefreshTaskRequest(identifier: SwiftWorkmanagerPlugin.defaultBGAppRefreshTaskIdentifier)
+
+       request.earliestBeginDate = Date(timeIntervalSinceNow: bgRefreshTaskFrequency * 60)
+
+       do {
+          try BGTaskScheduler.shared.submit(request)
+       } catch {
+          print("Could not schedule app refresh: \(error)")
+       }
+    }
+
+    @available(iOS 13.0, *)
+    private func handleAppRefresh(task: BGAppRefreshTask) {
+       print("handleAppRefresh()", task.identifier)
+        
+        if (bgRefreshTaskFrequency > 0) {
+            // Schedule a new refresh task.
+            scheduleAppRefresh()
+        }
+
+       let operationQueue = OperationQueue()
+
+       // Create an operation that performs the main part of the background task.
+       let operation = BackgroundTaskOperation(
+           task.identifier,
+           flutterPluginRegistrantCallback: SwiftWorkmanagerPlugin.flutterPluginRegistrantCallback
+       )
+
+       // Provide the background task with an expiration handler that cancels the operation.
+       task.expirationHandler = {
+          operation.cancel()
+       }
+
+       // Inform the system that the background task is complete
+       // when the operation completes.
+       operation.completionBlock = {
+          task.setTaskCompleted(success: !operation.isCancelled)
+       }
+
+       // Start the operation.
+       operationQueue.addOperation(operation)
+    }
+
     public override func application(_ application: UIApplication,
                                      didFinishLaunchingWithOptions launchOptions: [AnyHashable: Any] = [:]) -> Bool {
         if #available(iOS 13.0, *) {
@@ -88,6 +144,10 @@ public class SwiftWorkmanagerPlugin: FlutterPluginAppLifeCycleDelegate {
                     self.handleBGProcessingTask(task)
                 }
             }
+
+            BGTaskScheduler.shared.register(forTaskWithIdentifier: SwiftWorkmanagerPlugin.defaultBGAppRefreshTaskIdentifier, using: nil) { task in
+                 self.handleAppRefresh(task: task as! BGAppRefreshTask)
+            }
         }
 
         return true
@@ -128,24 +188,49 @@ extension SwiftWorkmanagerPlugin: FlutterPlugin {
             UserDefaultsHelper.storeIsDebug(isInDebug)
             result(true)
 
-        case (ForegroundMethodChannel.Methods.RegisterOneOffTask.name, let .some(arguments)):
-            if !validateCallbackHandle() {
-                result(
-                    FlutterError(
-                        code: "1",
-                        message: "You have not properly initialized the Flutter WorkManager Package. " +
-                            "You should ensure you have called the 'initialize' function first! " +
-                            "Example: \n" +
-                            "\n" +
-                            "`Workmanager().initialize(\n" +
-                            "  callbackDispatcher,\n" +
-                            " )`" +
-                            "\n" +
-                            "\n" +
-                            "The `callbackDispatcher` is a top level function. See example in repository.",
-                        details: nil
-                    )
+        case (ForegroundMethodChannel.Methods.RegisterAppRefreshTask.name, let .some(arguments)):
+            print("ForegroundMethodChannel.Methods.RegisterAppRefreshTask")
+            if !validateCallbackHandle(result: result) {
+                return
+            }
+
+            if #available(iOS 13.0, *) {
+                let method = ForegroundMethodChannel.Methods.RegisterAppRefreshTask.self
+                guard let initialDelaySeconds =
+                        arguments[method.Arguments.initialDelaySeconds.rawValue] as? Int64 else {
+                    result(WMPError.invalidParameters.asFlutterError)
+                    return
+                }
+
+                guard let regreshFrequencySeconds =
+                        arguments[method.Arguments.refreshFrequencySeconds.rawValue] as? Int64 else {
+                    result(WMPError.invalidParameters.asFlutterError)
+                    return
+                }
+
+                // save this, can't store in task
+                bgRefreshTaskFrequency = Double(regreshFrequencySeconds)
+                
+                let request = BGAppRefreshTaskRequest(
+                    identifier: SwiftWorkmanagerPlugin.defaultBGAppRefreshTaskIdentifier
                 )
+
+                request.earliestBeginDate = Date(timeIntervalSinceNow: Double(initialDelaySeconds))
+
+                do {
+                    try BGTaskScheduler.shared.submit(request)
+                    result(true)
+                } catch {
+                    result(WMPError.bgTaskSchedulingFailed(error).asFlutterError)
+                }
+
+                return
+            } else {
+                result(WMPError.unhandledMethod(call.method).asFlutterError)
+            }
+
+        case (ForegroundMethodChannel.Methods.RegisterOneOffTask.name, let .some(arguments)):
+            if !validateCallbackHandle(result: result) {
                 return
             }
 
@@ -207,8 +292,27 @@ extension SwiftWorkmanagerPlugin: FlutterPlugin {
         }
     }
 
-    private func validateCallbackHandle() -> Bool {
-        return UserDefaultsHelper.getStoredCallbackHandle() != nil
+    private func validateCallbackHandle(result: @escaping FlutterResult) -> Bool {
+        let valid = UserDefaultsHelper.getStoredCallbackHandle() != nil
+        if (!valid) {
+            result(
+                FlutterError(
+                    code: "1",
+                    message: "You have not properly initialized the Flutter WorkManager Package. " +
+                        "You should ensure you have called the 'initialize' function first! " +
+                        "Example: \n" +
+                        "\n" +
+                        "`Workmanager().initialize(\n" +
+                        "  callbackDispatcher,\n" +
+                        " )`" +
+                        "\n" +
+                        "\n" +
+                        "The `callbackDispatcher` is a top level function. See example in repository.",
+                    details: nil
+                )
+            )
+        }
+        return valid
     }
 }
 
diff --git a/lib/src/workmanager.dart b/lib/src/workmanager.dart
@@ -155,7 +155,7 @@ class Workmanager {
   /// Schedule a one off task
   /// A [uniqueName] is required so only one task can be registered.
   /// The [taskName] is the value that will be returned in the [BackgroundTaskHandler]
-  /// The [inputData] is the input data for task. Valid value types are: int, bool, double, String and their list
+  /// The [inputData] is the input data for task. Android Only. Valid value types are: int, bool, double, String and their list
   Future<void> registerOneOffTask(
     /// Only supported on Android.
     final String uniqueName,
@@ -200,6 +200,27 @@ class Workmanager {
         ),
       );
 
+  /// Schedule an iOS BGAppRefreshTask
+  Future<void> registerAppRefreshTask({
+
+    /// Configures an initial delay.
+    ///
+    /// The delay configured here is not guaranteed. The underlying system may
+    /// decide to schedule the task a lot later.
+    final Duration initialDelay = Duration.zero,
+
+    /// Frequency to repeat task after initial execution. Duration.zero does not repeat.
+    final Duration frequency = Duration.zero,
+  }) async =>
+      await _foregroundChannel.invokeMethod(
+        "registerAppRefreshTask",
+        JsonMapperHelper.toRegisterAppRefreshMethodArgument(
+          isInDebugMode: _isInDebugMode,
+          initialDelay: initialDelay,
+          frequency: frequency
+        ),
+      );
+
   /// Schedules a periodic task that will run every provided [frequency].
   /// A [uniqueName] is required so only one task can be registered.
   /// The [taskName] is the value that will be returned in the [BackgroundTaskHandler]
@@ -313,6 +334,19 @@ class JsonMapperHelper {
     };
   }
 
+  @visibleForTesting
+  static Map<String, Object?> toRegisterAppRefreshMethodArgument({
+    final bool isInDebugMode = false,
+    final Duration? initialDelay,
+    final Duration? frequency
+  }) {
+    return {
+      "isInDebugMode": isInDebugMode,
+      "initialDelaySeconds": initialDelay?.inSeconds,
+      "refreshFrequencySeconds": frequency?.inSeconds
+    };
+  }
+
   @visibleForTesting
   static Map<String, Object?> toInitializeMethodArgument({
     required final bool isInDebugMode,
