Add minimum time interval and default value to operation polling (#151)

* Implement `startPollingOperations` extension function with default TimeInterval

* Implement `minimumTimePollingInterval`

* Write docs

* Replace magic value with minimumTimePollingInterval

* Add changes to changelog

* Fix remarks

* Fix delay start condition

WultraMobileTokenSDK/Operations/Service/WMTOperationsImpl.swift

@@ -131,6 +131,7 @@ class WMTOperationsImpl<T: WMTUserOperation>: WMTOperations, WMTService {
     private var isPollingPaused: Bool { return pollingTimer?.isValid == false }
     private let pollingLock = WMTLock()
     private var notificationObservers = [NSObjectProtocol]()
+    private let minimumTimePollingInterval = 5.0
 
     /// Operation register holds operations in order
     private lazy var operationsRegister = OperationsRegister { [weak self] ops, added, removed in
@@ -364,8 +365,17 @@ class WMTOperationsImpl<T: WMTUserOperation>: WMTOperations, WMTService {
             refreshOperations()
         }
 
-        D.print("Operations polling started with \(interval) seconds interval")
-        pollingTimer = Timer.scheduledTimer(withTimeInterval: interval, repeats: true) { [weak self] _ in
+        // Set the minimum TimeInterval
+        var adjustedInterval: TimeInterval
+        if interval < minimumTimePollingInterval {
+            D.warning("Operations polling interval: \(interval), must not be set below \(minimumTimePollingInterval) to prevent server overload.")
+            adjustedInterval = minimumTimePollingInterval
+        } else {
+            adjustedInterval = interval
+        }
+
+        D.print("Operations polling started with \(adjustedInterval) seconds interval")
+        pollingTimer = Timer.scheduledTimer(withTimeInterval: adjustedInterval, repeats: true) { [weak self] _ in
             self?.refreshOperations()
         }
     }
@@ -396,8 +406,6 @@ class WMTOperationsImpl<T: WMTUserOperation>: WMTOperations, WMTService {
             return
         }
 
-        let requestStartDate = Date()
-
         networking.post(data: .init(), signedWith: .possession(), to: WMTOperationEndpoints.List<T>.endpoint) { response, error in
 
             assert(Thread.isMainThread)

WultraMobileTokenSDK/Operations/WMTOperations.swift

@@ -127,7 +127,7 @@ public protocol WMTOperations: AnyObject {
     ///
     /// If operations are already polling this call is ignored and
     /// polling interval won't be changed.
-    /// - Parameter interval: Polling interval
+    /// - Parameter interval: Polling interval, minimum is 5s
     /// - Parameter delayStart: When true, polling starts after
     ///                         the first `interval` time passes
     func startPollingOperations(interval: TimeInterval, delayStart: Bool)
@@ -155,6 +155,18 @@ public extension WMTOperations {
     func authorize(qrOperation: WMTQROperation, authentication: PowerAuthAuthentication, completion: @escaping (Result<String, WMTError>) -> Void) -> Operation {
         return authorize(qrOperation: qrOperation, uriId: "/operation/authorize/offline", authentication: authentication, completion: completion)
     }
+
+    /// Starts the operations polling.
+    ///
+    /// Deafula implementation of startPollingOperations
+    /// The `interval` is set to 7 seconds, with a minimum value of 5 seconds.
+    ///
+    /// - Parameters:
+    ///   - interval: Default is set to 7 seconds, with a minimum value of 5 seconds.
+    ///   - delayStart: Default is set to false and polling starts immediately.
+    func startPollingOperations() {
+        return startPollingOperations(interval: 7, delayStart: false)
+    }
 }
 
 public typealias GetOperationsResult = Result<[WMTUserOperation], WMTError>

WultraMobileTokenSDKTests/IntegrationTests.swift

@@ -356,16 +356,16 @@ class IntegrationTests: XCTestCase {
         XCTAssertFalse(ops.isPollingOperations)
         let delegate = OpDelegate()
         delegate.loadingCountCallback = { count in
-            if count == 4 {
+            if count == 3 {
                 self.ops.stopPollingOperations()
                 exp.fulfill()
             }
         }
         ops.delegate = delegate
-        ops.startPollingOperations(interval: 1, delayStart: false)
+        ops.startPollingOperations()
         XCTAssertTrue(ops.isPollingOperations)
 
-        waitForExpectations(timeout: 20, handler: nil)
+        waitForExpectations(timeout: 30, handler: nil)
 
         XCTAssertFalse(ops.isPollingOperations)
     }

docs/Changelog.md

@@ -3,6 +3,7 @@
 ## 1.10.0
 
 - Removed `currentServerTime` property [(#148)](https://github.com/wultra/mtoken-sdk-android/pull/139)
+- Added default and minimum pollingInterval [(#151)](https://github.com/wultra/mtoken-sdk-ios/pull/151)
 
 ## 1.9.0 (Jan 24, 2024)
 

docs/Using-Operations-Service.md

@@ -107,6 +107,12 @@ if (!operationsService.isPollingOperations) {
 }
 ```
 
+### Default and Minimum TimeInterval Enforcement
+
+For convenience, there is a default implementation where you can omit the polling interval and it is automatically set to 7 seconds. If you specify an interval below 5 seconds, it will be automatically adjusted to 5 seconds to prevent server overload.
+
+### Setting up a delegate
+
 To receive the result of the polling, set up a delegate.
 
 <!-- begin box warning -->
@@ -148,6 +154,10 @@ class MyOperationsManager: WMTOperationsDelegate {
 Polling behavior can be adjusted by the `pollingOptions` parameter when [creating an instance](#creating-an-instance) of the service.
 <!-- end -->
 
+### Best Practices and Recommendations
+
+For optimal server performance, consider adjusting polling intervals based on your application's requirements. For instance, when push notifications are enabled, it's advisable to double the polling interval to minimize server load.
+
 ## Approve an Operation
 
 To approve an operation use `WMTOperations.authorize`. You can simply use it with the following examples: