Modifies TaskProgressUpdate interval

Now, if progress is available, a progress update will be sent at least once every 2.5 seconds, even if less than 2% progress has been made. This helps keep UI notifications alive for large and slow loading files.

README.md

@@ -223,7 +223,7 @@ If you want to monitor progress during the download itself (e.g. for a large fil
 final result = await FileDownloader().download(task, 
     onProgress: (progress) => print('Progress update: $progress'));
 ```
-Progress updates start with 0.0 when the actual download starts (which may be in the future, e.g. if waiting for a WiFi connection), and will be sent periodically, not more than twice per second per task.  If a task completes successfully you will receive a final progress update with a `progress` value of 1.0 (`progressComplete`). Failed tasks generate `progress` of `progressFailed` (-1.0), canceled tasks `progressCanceled` (-2.0), notFound tasks `progressNotFound` (-3.0), waitingToRetry tasks `progressWaitingToRetry` (-4.0) and paused tasks `progressPaused` (-5.0).
+Progress updates start with 0.0 when the actual download starts (which may be in the future, e.g. if waiting for a WiFi connection), and will be sent periodically, not more than twice per second per task, and not less than once every 2.5 seconds.  If a task completes successfully you will receive a final progress update with a `progress` value of 1.0 (`progressComplete`). Failed tasks generate `progress` of `progressFailed` (-1.0), canceled tasks `progressCanceled` (-2.0), notFound tasks `progressNotFound` (-3.0), waitingToRetry tasks `progressWaitingToRetry` (-4.0) and paused tasks `progressPaused` (-5.0).
 
 Use `await task.expectedFileSize()` to query the server for the size of the file you are about
 to download.  The expected file size is also included in `TaskProgressUpdate`s that are sent to
@@ -362,7 +362,7 @@ In summary, to track your tasks persistently, follow these steps in order, immed
 3. Call `await FileDownloader().start()` to execute the following calls in the correct order (or call these manually):
    a. Call `await FileDownloader().trackTasks()` if you want to track the tasks in a persistent database
    b. Call `await FileDownloader().resumeFromBackground()` to ensure events that happened while your app was in the background are processed
-   c. If you are tracking tasks in the database, after ~5 seconds, call `await FileDownloader().rescheduleKilledTasks()` to reschedule tasks that are in the database as `enqueued` or `running` yet are not enqueued or running on the native side. These tasks have been "lost", most likely because the user killed your app (which kills tasks on the native side without warning)
+   c. If you are tracking tasks in the database, after ~5 seconds, call `await FileDownloader().rescheduleKilledTasks()` to reschedule tasks that are in the database as `enqueued` or `running` yet are not enqueued or running on the native side, or that are `waitingToRetry` but not registered as such. These tasks have been "lost", most likely because the user killed your app (which kills tasks on the native side without warning)
 
 The rest of this section details [event listeners](#using-an-event-listener), [callbacks](#using-callbacks) and the [database](#using-the-database-to-track-tasks) in detail.
 
@@ -452,7 +452,7 @@ print('TaskId ${record.taskId} with task ${record.task} has '
 You can interact with the `database` using `allRecords`, `allRecordsOlderThan`, `recordForId`,`deleteAllRecords`,
 `deleteRecordWithId` etc. If you only want to track tasks in a specific [group](#grouping-tasks), call `trackTasksInGroup` instead.
 
-If a user kills your app (e.g. by swiping it away in the app tray) then tasks that are running (natively) are killed, and no indication is given to your application. This cannot be avoided. To guard for this, upon app startup you can ask the downloader to reschedule killed tasks, i.e. tasks that show up as `enqueued` or `running` in the database, yet are not enqueued or running on the native side. Method `rescheduleKilledTasks` returns a record with two lists, 1) successfully rescheduled tasks and 2) tasks that failed to reschedule. Together, those are the missing tasks. Reschedule missing tasks a few seconds after you have called `resumeFromBackground`, as that gives the downloader time to processes updates that may have happened while the app was suspended, or call `FileDownloader().start()` with `doRescheduleKilledTasks` set to true (the default).
+If a user kills your app (e.g. by swiping it away in the app tray) then tasks that are running (natively) are killed, and no indication is given to your application. This cannot be avoided. To guard for this, upon app startup you can ask the downloader to reschedule killed tasks, i.e. tasks that show up as `enqueued` or `running` in the database, yet are not enqueued or running on the native side, or are `waitingToRetry` but not registered as such. Method `rescheduleKilledTasks` returns a record with two lists, 1) successfully rescheduled tasks and 2) tasks that failed to reschedule. Together, those are the missing tasks. Reschedule missing tasks a few seconds after you have called `resumeFromBackground`, as that gives the downloader time to processes updates that may have happened while the app was suspended, or call `FileDownloader().start()` with `doRescheduleKilledTasks` set to true (the default).
 
 By default, the downloader uses a modified version of the [localstore](https://pub.dev/packages/localstore) package to store the `TaskRecord` and other objects. To use a different persistent storage solution, create a class that implements the [PersistentStorage](https://pub.dev/documentation/background_downloader/latest/background_downloader/PersistentStorage-class.html) interface, and initialize the downloader by calling `FileDownloader(persistentStorage: MyPersistentStorage())` as the first use of the `FileDownloader`.
 

android/src/main/kotlin/com/bbflight/background_downloader/TaskWorker.kt

@@ -671,12 +671,14 @@ open class TaskWorker(
     }
 
     /**
-     * Returns true if [currentProgress] > [lastProgressUpdate] + threshold and
-     * [now] > [nextProgressUpdateTime]
+     * Returns true if [currentProgress] > [lastProgressUpdate] + 2% and
+     * [now] > [nextProgressUpdateTime], or if there was progress and
+     * [now] > [nextProgressUpdateTime] + 2 seconds
      */
     open fun shouldSendProgressUpdate(currentProgress: Double, now: Long): Boolean {
-        return currentProgress - lastProgressUpdate > 0.02 &&
-                now > nextProgressUpdateTime
+        return (currentProgress - lastProgressUpdate > 0.02 &&
+                now > nextProgressUpdateTime) || (currentProgress > lastProgressUpdate &&
+                now > nextProgressUpdateTime + 2000)
     }
 
     /**

example/integration_test/downloader_integration_test.dart

@@ -505,6 +505,7 @@ void main() {
       final subscription = FileDownloader().updates.listen((update) {
         expect(update is TaskProgressUpdate, isTrue);
         if (update is TaskProgressUpdate) {
+          print("ProgressUpdate ${update.progress} at ${DateTime.now()}");
           progressCallback(update);
         }
       });

example/macos/Runner.xcodeproj/project.pbxproj

@@ -26,6 +26,7 @@
 		33CC10F32044A3C60003C045 /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 33CC10F22044A3C60003C045 /* Assets.xcassets */; };
 		33CC10F62044A3C60003C045 /* MainMenu.xib in Resources */ = {isa = PBXBuildFile; fileRef = 33CC10F42044A3C60003C045 /* MainMenu.xib */; };
 		33CC11132044BFA00003C045 /* MainFlutterWindow.swift in Sources */ = {isa = PBXBuildFile; fileRef = 33CC11122044BFA00003C045 /* MainFlutterWindow.swift */; };
+		78A318202AECB46A00862997 /* FlutterGeneratedPluginSwiftPackage in Frameworks */ = {isa = PBXBuildFile; productRef = 78A3181F2AECB46A00862997 /* FlutterGeneratedPluginSwiftPackage */; };
 		7A5FBE1A8A4574067AE99057 /* Pods_Runner.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 327E02FF0D7765B97772BC21 /* Pods_Runner.framework */; };
 /* End PBXBuildFile section */
 
@@ -81,6 +82,7 @@
 			isa = PBXFrameworksBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				78A318202AECB46A00862997 /* FlutterGeneratedPluginSwiftPackage in Frameworks */,
 				7A5FBE1A8A4574067AE99057 /* Pods_Runner.framework in Frameworks */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
@@ -185,14 +187,16 @@
 				33CC10EB2044A3C60003C045 /* Resources */,
 				33CC110E2044A8840003C045 /* Bundle Framework */,
 				3399D490228B24CF009A79C7 /* ShellScript */,
-				50F2B87867DEB156BA98A61F /* [CP] Embed Pods Frameworks */,
 			);
 			buildRules = (
 			);
 			dependencies = (
 				33CC11202044C79F0003C045 /* PBXTargetDependency */,
 			);
 			name = Runner;
+			packageProductDependencies = (
+				78A3181F2AECB46A00862997 /* FlutterGeneratedPluginSwiftPackage */,
+			);
 			productName = Runner;
 			productReference = 33CC10ED2044A3C60003C045 /* example.app */;
 			productType = "com.apple.product-type.application";
@@ -232,6 +236,9 @@
 				Base,
 			);
 			mainGroup = 33CC10E42044A3C60003C045;
+			packageReferences = (
+				781AD8BC2B33823900A9FFBB /* XCLocalSwiftPackageReference "FlutterGeneratedPluginSwiftPackage" */,
+			);
 			productRefGroup = 33CC10EE2044A3C60003C045 /* Products */;
 			projectDirPath = "";
 			projectRoot = "";
@@ -293,23 +300,6 @@
 			shellPath = /bin/sh;
 			shellScript = "\"$FLUTTER_ROOT\"/packages/flutter_tools/bin/macos_assemble.sh && touch Flutter/ephemeral/tripwire";
 		};
-		50F2B87867DEB156BA98A61F /* [CP] Embed Pods Frameworks */ = {
-			isa = PBXShellScriptBuildPhase;
-			buildActionMask = 2147483647;
-			files = (
-			);
-			inputFileListPaths = (
-				"${PODS_ROOT}/Target Support Files/Pods-Runner/Pods-Runner-frameworks-${CONFIGURATION}-input-files.xcfilelist",
-			);
-			name = "[CP] Embed Pods Frameworks";
-			outputFileListPaths = (
-				"${PODS_ROOT}/Target Support Files/Pods-Runner/Pods-Runner-frameworks-${CONFIGURATION}-output-files.xcfilelist",
-			);
-			runOnlyForDeploymentPostprocessing = 0;
-			shellPath = /bin/sh;
-			shellScript = "\"${PODS_ROOT}/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh\"\n";
-			showEnvVarsInLog = 0;
-		};
 		BDB2605E80924098FA31483D /* [CP] Check Pods Manifest.lock */ = {
 			isa = PBXShellScriptBuildPhase;
 			buildActionMask = 2147483647;
@@ -629,6 +619,20 @@
 			defaultConfigurationName = Release;
 		};
 /* End XCConfigurationList section */
+
+/* Begin XCLocalSwiftPackageReference section */
+		781AD8BC2B33823900A9FFBB /* XCLocalSwiftPackageReference "FlutterGeneratedPluginSwiftPackage" */ = {
+			isa = XCLocalSwiftPackageReference;
+			relativePath = Flutter/ephemeral/Packages/FlutterGeneratedPluginSwiftPackage;
+		};
+/* End XCLocalSwiftPackageReference section */
+
+/* Begin XCSwiftPackageProductDependency section */
+		78A3181F2AECB46A00862997 /* FlutterGeneratedPluginSwiftPackage */ = {
+			isa = XCSwiftPackageProductDependency;
+			productName = FlutterGeneratedPluginSwiftPackage;
+		};
+/* End XCSwiftPackageProductDependency section */
 	};
 	rootObject = 33CC10E52044A3C60003C045 /* Project object */;
 }

example/macos/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

@@ -5,6 +5,24 @@
    <BuildAction
       parallelizeBuildables = "YES"
       buildImplicitDependencies = "YES">
+      <PreActions>
+         <ExecutionAction
+            ActionType = "Xcode.IDEStandardExecutionActionsCore.ExecutionActionType.ShellScriptAction">
+            <ActionContent
+               title = "Run Prepare Flutter Framework Script"
+               scriptText = "&quot;$FLUTTER_ROOT&quot;/packages/flutter_tools/bin/macos_assemble.sh prepare&#10;">
+               <EnvironmentBuildable>
+                  <BuildableReference
+                     BuildableIdentifier = "primary"
+                     BlueprintIdentifier = "33CC10EC2044A3C60003C045"
+                     BuildableName = "example.app"
+                     BlueprintName = "Runner"
+                     ReferencedContainer = "container:Runner.xcodeproj">
+                  </BuildableReference>
+               </EnvironmentBuildable>
+            </ActionContent>
+         </ExecutionAction>
+      </PreActions>
       <BuildActionEntries>
          <BuildActionEntry
             buildForTesting = "YES"

ios/background_downloader/Sources/background_downloader/TaskFunctions.swift

@@ -296,9 +296,10 @@ func updateProgress(task: Task, totalBytesExpected: Int64, totalBytesDone: Int64
     let info = BDPlugin.propertyLock.withLock({
         return BDPlugin.progressInfo[task.taskId] ?? (lastProgressUpdateTime: 0.0, lastProgressValue: 0.0, lastTotalBytesDone: 0, lastNetworkSpeed: -1.0)
     })
-    if totalBytesExpected != NSURLSessionTransferSizeUnknown && Date().timeIntervalSince1970 > info.lastProgressUpdateTime + 0.5 {
+    let now = Date().timeIntervalSince1970
+    if totalBytesExpected != NSURLSessionTransferSizeUnknown && now > info.lastProgressUpdateTime + 0.5 {
         let progress = min(Double(totalBytesDone) / Double(totalBytesExpected), 0.999)
-        if progress - info.lastProgressValue > 0.02 {
+        if (progress - info.lastProgressValue > 0.02) || (progress > info.lastProgressValue && now > info.lastProgressUpdateTime + 2.5) {
             // calculate network speed and time remaining
             let now = Date().timeIntervalSince1970
             let timeSinceLastUpdate = now - info.lastProgressUpdateTime

ios/background_downloader/Sources/background_downloader/UrlSessionDelegate.swift

@@ -150,8 +150,8 @@ public class UrlSessionDelegate : NSObject, URLSessionDelegate, URLSessionDownlo
 
     /// Process taskdelegate progress update for download task
     ///
-    /// If the task requires progress updates, provide these at a reasonable interval
-    /// If this is the first update for this file, also emit a 'running' status update
+    /// If the task requires progress updates, provides these at a reasonable interval
+    /// If this is the first update for this file, also emits a 'running' status update
     public func urlSession(_ session: URLSession, downloadTask: URLSessionDownloadTask, didWriteData bytesWritten: Int64, totalBytesWritten: Int64, totalBytesExpectedToWrite: Int64) {
         // task is var because the filename can be changed on the first 'didWriteData' call
         guard var task = getTaskFrom(urlSessionTask: downloadTask) else { return }

lib/src/desktop/isolate.dart

@@ -435,9 +435,11 @@ Future<String?> responseContent(http.StreamedResponse response) {
   }
 }
 
-/// Returns true if [currentProgress] > [lastProgressUpdate] + threshold and
-/// [now] > [nextProgressUpdateTime]
-bool shouldSendProgressUpdate(double currentProgress, DateTime now) {
-  return currentProgress - lastProgressUpdate > 0.02 &&
-      now.isAfter(nextProgressUpdateTime);
-}
+/// Returns true if [currentProgress] > [lastProgressUpdate] + 2% and
+/// [now] > [nextProgressUpdateTime], or if there was progress and
+/// [now] > [nextProgressUpdateTime] + 2 seconds
+bool shouldSendProgressUpdate(double currentProgress, DateTime now) =>
+    (currentProgress - lastProgressUpdate > 0.02 &&
+        now.isAfter(nextProgressUpdateTime)) ||
+    (currentProgress > lastProgressUpdate &&
+        now.isAfter(nextProgressUpdateTime.add(const Duration(seconds: 2))));