OSMessagingController Retry Logic

Motivation: retry logic should work as follows:
1. initial request with offset --> failure
2. get retry limit & retry after from response & start retrying
3. if hit limit, make one final request with the offset: 0

The final request tells the backend, just show me what you got.

Example: If the retry limit is 3 & we never get a successful response retrying, we should end up with 5 total requests.

iOS_SDK/OneSignalSDK/OneSignalInAppMessages/Controller/OSMessagingController.m

@@ -1,7 +1,7 @@
 /**
  * Modified MIT License
  *
- * Copyright 2017 OneSignal
+ * Copyright 2024 OneSignal
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -35,8 +35,13 @@
 #import "OSInAppMessagePrompt.h"
 #import "OSInAppMessagingRequests.h"
 #import "OneSignalWebViewManager.h"
+#import "OneSignalTracker.h"
 #import <OneSignalOutcomes/OneSignalOutcomes.h>
 #import "OSSessionManager.h"
+#import "OneSignalOSCore/OneSignalOSCore-Swift.h"
+
+static NSInteger const DEFAULT_RETRY_AFTER_SECONDS = 1;  // Default 1 second retry delay
+static NSInteger const DEFAULT_RETRY_LIMIT = 3;          // Default retry limit
 
 @implementation OSInAppMessageWillDisplayEvent
 
@@ -248,16 +253,48 @@ - (void)getInAppMessagesFromServer:(NSString *)subscriptionId {
         [self updateInAppMessagesFromCache];
         return;
     }
-
-    OSRequestGetInAppMessages *request = [OSRequestGetInAppMessages withSubscriptionId:subscriptionId];
-    [OneSignalCoreImpl.sharedClient executeRequest:request onSuccess:^(NSDictionary *result) {
+
+    OSConsistencyManager *consistencyManager = [OSConsistencyManager shared];
+    NSString *onesignalId = OneSignalUserManagerImpl.sharedInstance.onesignalId;
+
+    if (!onesignalId) {
+        [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:@"Failed to get in app messages due to no OneSignal ID"];
+        return;
+    }
+
+    OSIamFetchReadyCondition *condition = [[OSIamFetchReadyCondition alloc] initWithId:onesignalId];
+    NSString *newestOffset = [consistencyManager registerCondition:condition forId:onesignalId];
+
+    NSNumber *sessionDuration = @([OSSessionManager getTimeFocusedElapsed]);
+
+    // Initial request
+    [self attemptFetchWithRetries:subscriptionId
+                           rywToken:newestOffset
+                  sessionDuration:sessionDuration
+                          attempts:1];
+}
+
+- (void)attemptFetchWithRetries:(NSString *)subscriptionId
+                         rywToken:(NSString *)rywToken
+                sessionDuration:(NSNumber *)sessionDuration
+                        attempts:(NSInteger)attempts {
+
+    NSInteger retryCount = (attempts > 1) ? (attempts - 1) : 0;
+
+    OSRequestGetInAppMessages *request = [OSRequestGetInAppMessages withSubscriptionId:subscriptionId
+                                                                      withSessionDuration:sessionDuration
+                                                                      withRetryCount:@(retryCount)
+                                                                          withRywToken:rywToken];
+
+    [OneSignalCoreImpl.sharedClient executeRequest:request
+                                          onSuccess:^(NSDictionary *result) {
         dispatch_async(dispatch_get_main_queue(), ^{
             [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:@"getInAppMessagesFromServer success"];
-            if (result[@"in_app_messages"]) { // when there are no IAMs, will this still be there?
-                let messages = [NSMutableArray new];
+            if (result[@"in_app_messages"]) {
+                NSMutableArray *messages = [NSMutableArray new];
 
                 for (NSDictionary *messageJson in result[@"in_app_messages"]) {
-                    let message = [OSInAppMessageInternal instanceWithJson:messageJson];
+                    OSInAppMessageInternal *message = [OSInAppMessageInternal instanceWithJson:messageJson];
                     if (message) {
                         [messages addObject:message];
                     }
@@ -266,11 +303,80 @@ - (void)getInAppMessagesFromServer:(NSString *)subscriptionId {
                 [self updateInAppMessagesFromServer:messages];
                 return;
             }
-
-            // TODO: Check this request and response. If no IAMs returned, should we really get from cache?
-            // This is the existing implementation but it could mean this user has no IAMs?
-
-            // Default is using cached IAMs in the messaging controller
+            [self updateInAppMessagesFromCache];
+        });
+    }
+    onFailure:^(NSError *error) {
+        NSDictionary *errorInfo = error.userInfo[@"returned"];
+        NSNumber *statusCode = errorInfo[@"httpStatusCode"];
+
+        if (!statusCode) {
+            [self updateInAppMessagesFromCache];
+            return;
+        }
+
+        [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:[NSString stringWithFormat:@"getInAppMessagesFromServer failure: %@", error.localizedDescription]];
+
+        NSInteger code = [statusCode integerValue];
+        if (code == 425 || code == 429) { // 425 Too Early or 429 Too Many Requests
+            NSInteger retryAfter = [errorInfo[@"OneSignal-Retry-After"] integerValue] ?: DEFAULT_RETRY_AFTER_SECONDS;
+            NSInteger retryLimit = [errorInfo[@"OneSignal-Retry-Limit"] integerValue] ?: DEFAULT_RETRY_LIMIT;
+
+            if (attempts <= retryLimit) {
+                [self retryAfterDelay:retryAfter
+                         subscriptionId:subscriptionId
+                                rywToken:rywToken
+                       sessionDuration:sessionDuration
+                               attempts:attempts];
+            } else {
+                // Final attempt with offset = 0
+                [self fetchInAppMessagesWithoutOffset:subscriptionId sessionDuration:sessionDuration];
+            }
+        } else {
+            [self updateInAppMessagesFromCache];
+        }
+    }];
+}
+
+- (void)retryAfterDelay:(NSInteger)retryAfter
+          subscriptionId:(NSString *)subscriptionId
+                 rywToken:(NSString *)rywToken
+        sessionDuration:(NSNumber *)sessionDuration
+               attempts:(NSInteger)attempts {
+
+    dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(retryAfter * NSEC_PER_SEC)), dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
+        [self attemptFetchWithRetries:subscriptionId
+                              rywToken:rywToken
+                     sessionDuration:sessionDuration
+                             attempts:attempts + 1]; // No more delayTime argument
+    });
+}
+
+- (void)fetchInAppMessagesWithoutOffset:(NSString *)subscriptionId
+                        sessionDuration:(NSNumber *)sessionDuration {
+
+    OSRequestGetInAppMessages *request = [OSRequestGetInAppMessages withSubscriptionId:subscriptionId
+                                                                      withSessionDuration:sessionDuration
+                                                                      withRetryCount:@0
+                                                                      withRywToken:nil]; // No retries for the final attempt
+
+    [OneSignalCoreImpl.sharedClient executeRequest:request
+                                          onSuccess:^(NSDictionary *result) {
+        dispatch_async(dispatch_get_main_queue(), ^{
+            [OneSignalLog onesignalLog:ONE_S_LL_VERBOSE message:@"Final attempt without offset success"];
+            if (result[@"in_app_messages"]) {
+                NSMutableArray *messages = [NSMutableArray new];
+
+                for (NSDictionary *messageJson in result[@"in_app_messages"]) {
+                    OSInAppMessageInternal *message = [OSInAppMessageInternal instanceWithJson:messageJson];
+                    if (message) {
+                        [messages addObject:message];
+                    }
+                }
+
+                [self updateInAppMessagesFromServer:messages];
+                return;
+            }
             [self updateInAppMessagesFromCache];
         });
     } onFailure:^(NSError *error) {