fix: ensure batch array in the request payload is never empty

Examples/RudderSampleAppObjC/RudderSampleAppObjC.xcodeproj/project.pbxproj

@@ -12,7 +12,6 @@
 		6003F58E195388D20070C39A /* Foundation.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F58D195388D20070C39A /* Foundation.framework */; };
 		6003F590195388D20070C39A /* CoreGraphics.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F58F195388D20070C39A /* CoreGraphics.framework */; };
 		6003F592195388D20070C39A /* UIKit.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 6003F591195388D20070C39A /* UIKit.framework */; };
-		ED0CA6DD2A7D049E00899C1C /* RudderConfig.plist in Resources */ = {isa = PBXBuildFile; fileRef = ED0CA6DA2A7D049E00899C1C /* RudderConfig.plist */; };
 		ED0CA6DE2A7D049E00899C1C /* SampleRudderConfig.plist in Resources */ = {isa = PBXBuildFile; fileRef = ED0CA6DB2A7D049E00899C1C /* SampleRudderConfig.plist */; };
 		ED0CA6DF2A7D049E00899C1C /* RudderConfig.swift in Sources */ = {isa = PBXBuildFile; fileRef = ED0CA6DC2A7D049E00899C1C /* RudderConfig.swift */; };
 		ED7619FF2727E28800B086F4 /* InfoPlist.strings in Resources */ = {isa = PBXBuildFile; fileRef = ED7619ED2727E28700B086F4 /* InfoPlist.strings */; };
@@ -37,7 +36,6 @@
 		6003F591195388D20070C39A /* UIKit.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = UIKit.framework; path = System/Library/Frameworks/UIKit.framework; sourceTree = SDKROOT; };
 		6003F5AF195388D20070C39A /* XCTest.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = XCTest.framework; path = Library/Frameworks/XCTest.framework; sourceTree = DEVELOPER_DIR; };
 		ED0CA6D62A7D048D00899C1C /* RudderSampleAppObjC-Bridging-Header.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "RudderSampleAppObjC-Bridging-Header.h"; sourceTree = "<group>"; };
-		ED0CA6DA2A7D049E00899C1C /* RudderConfig.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; path = RudderConfig.plist; sourceTree = "<group>"; };
 		ED0CA6DB2A7D049E00899C1C /* SampleRudderConfig.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; path = SampleRudderConfig.plist; sourceTree = "<group>"; };
 		ED0CA6DC2A7D049E00899C1C /* RudderConfig.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = RudderConfig.swift; sourceTree = "<group>"; };
 		ED3B022F272A67AB000893AA /* RudderSampleAppObjC.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = RudderSampleAppObjC.entitlements; sourceTree = "<group>"; };
@@ -121,7 +119,6 @@
 		ED0CA6D92A7D049E00899C1C /* RudderConfig */ = {
 			isa = PBXGroup;
 			children = (
-				ED0CA6DA2A7D049E00899C1C /* RudderConfig.plist */,
 				ED0CA6DB2A7D049E00899C1C /* SampleRudderConfig.plist */,
 				ED0CA6DC2A7D049E00899C1C /* RudderConfig.swift */,
 			);
@@ -218,7 +215,6 @@
 			buildActionMask = 2147483647;
 			files = (
 				ED761A012727E28800B086F4 /* LaunchScreen.storyboard in Resources */,
-				ED0CA6DD2A7D049E00899C1C /* RudderConfig.plist in Resources */,
 				ED0CA6DE2A7D049E00899C1C /* SampleRudderConfig.plist in Resources */,
 				ED761A052727E28800B086F4 /* Images.xcassets in Resources */,
 				ED7619FF2727E28800B086F4 /* InfoPlist.strings in Resources */,

Podfile.lock

@@ -34,4 +34,4 @@ SPEC CHECKSUMS:
 
 PODFILE CHECKSUM: 799e2be1c19caac49a14db2f15e20e189c476219
 
-COCOAPODS: 1.12.0
+COCOAPODS: 1.11.3

Sources/Classes/Headers/Public/RSUtils.h

@@ -44,6 +44,8 @@ NS_ASSUME_NONNULL_BEGIN
 + (NSString* _Nullable) getDeviceId;
 + (BOOL)isFileExists:(NSString *)fileName;
 + (BOOL)removeFile:(NSString *)fileName;
++ (BOOL) isDBMessageEmpty:(RSDBMessage*)dbMessage;
++ (BOOL) isEmptyString:(NSString *)value;
 
 extern unsigned int MAX_EVENT_SIZE;
 extern unsigned int MAX_BATCH_SIZE;

Sources/Classes/RSCloudModeManager.m

@@ -46,13 +46,15 @@ - (void) startCloudModeProcessor {
                 [RSLogger logDebug:[[NSString alloc] initWithFormat:@"RSCloudModeManager: CloudModeProcessor: Payload: %@", payload]];
                 [RSLogger logInfo:[[NSString alloc] initWithFormat:@"RSCloudModeManager: CloudModeProcessor: EventCount: %lu", (unsigned long)dbMessage.messageIds.count]];
                 [RSMetricsReporter report:SDKMETRICS_CM_EVENT forMetricType:COUNT withProperties:@{SDKMETRICS_TYPE: SDKMETRICS_MESSAGES} andValue:(float)dbMessage.messages.count];
-                response = [strongSelf->networkManager sendNetworkRequest:payload toEndpoint:BATCH_ENDPOINT withRequestMethod:POST];
-                if (response.state == NETWORK_SUCCESS) {
-                    [RSLogger logDebug:[[NSString alloc] initWithFormat:@"RSCloudModeManager: CloudModeProcessor: Updating status as CLOUDMODEPROCESSING DONE for events (%@)",[RSUtils getCSVString:dbMessage.messageIds]]];
-                    [RSMetricsReporter report:SDKMETRICS_CM_ATTEMPT_SUCCESS forMetricType:COUNT withProperties:nil andValue:(float)dbMessage.messages.count];
-                    [strongSelf->dbPersistentManager updateEventsWithIds:dbMessage.messageIds withStatus:CLOUD_MODE_PROCESSING_DONE];
-                    [strongSelf->dbPersistentManager clearProcessedEventsFromDB];
-                    sleepCount = 0;
+                if (payload != nil) {
+                    response = [strongSelf->networkManager sendNetworkRequest:payload toEndpoint:BATCH_ENDPOINT withRequestMethod:POST];
+                    if (response.state == NETWORK_SUCCESS) {
+                        [RSLogger logDebug:[[NSString alloc] initWithFormat:@"RSCloudModeManager: CloudModeProcessor: Updating status as CLOUDMODEPROCESSING DONE for events (%@)",[RSUtils getCSVString:dbMessage.messageIds]]];
+                        [RSMetricsReporter report:SDKMETRICS_CM_ATTEMPT_SUCCESS forMetricType:COUNT withProperties:nil andValue:(float)dbMessage.messages.count];
+                        [strongSelf->dbPersistentManager updateEventsWithIds:dbMessage.messageIds withStatus:CLOUD_MODE_PROCESSING_DONE];
+                        [strongSelf->dbPersistentManager clearProcessedEventsFromDB];
+                        sleepCount = 0;
+                    }
                 }
             }
             [strongSelf->lock unlock];
@@ -78,6 +80,10 @@ - (void) startCloudModeProcessor {
 }
 
 + (NSString*) getPayloadFromMessages: (RSDBMessage*)dbMessage{
+    if ([RSUtils isDBMessageEmpty:dbMessage]) {
+        [RSLogger logDebug:@"Payload construction aborted because the dbMessage is empty."];
+        return nil;
+    }
     NSMutableArray<NSString *>* messages = dbMessage.messages;
     NSMutableArray<NSString *>* messageIds = dbMessage.messageIds;
     NSMutableArray<NSString *> *batchMessageIds = [[NSMutableArray alloc] init];
@@ -90,6 +96,7 @@ + (NSString*) getPayloadFromMessages: (RSDBMessage*)dbMessage{
     [json appendFormat:@"\"sentAt\":\"%@\",", sentAt];
     [json appendString:@"\"batch\":["];
     unsigned int totalBatchSize = [RSUtils getUTF8Length:json] + 2; // we add 2 characters at the end
+    NSMutableString* batchMessage = [[NSMutableString alloc] init];
     for (int index = 0; index < messages.count; index++) {
         NSMutableString* message = [[NSMutableString alloc] initWithString:messages[index]];
         long length = message.length;
@@ -103,9 +110,15 @@ + (NSString*) getPayloadFromMessages: (RSDBMessage*)dbMessage{
             [RSMetricsReporter report:SDKMETRICS_EVENTS_DISCARDED forMetricType:COUNT withProperties:@{SDKMETRICS_TYPE: SDKMETRICS_BATCH_SIZE_INVALID} andValue:1];
             break;
         }
-        [json appendString:message];
+        [batchMessage appendString:message];
         [batchMessageIds addObject:messageIds[index]];
     }
+    // When empty batch is sent to the server it trigger Invalid JSON error. Hence it is necessary to ensure that batch is not empty.
+    if ([RSUtils isEmptyString:batchMessage]) {
+        [RSLogger logDebug:@"Payload construction aborted because the batch message is empty."];
+        return nil;
+    }
+    [json appendString:batchMessage];
     if([json characterAtIndex:[json length]-1] == ',') {
         // remove trailing ','
         [json deleteCharactersInRange:NSMakeRange([json length]-1, 1)];

Sources/Classes/RSConfigBuilder.m

@@ -60,6 +60,9 @@ - (instancetype) withFlushQueueSize: (int) flushQueueSize {
     if (config == nil) {
         config = [[RSConfig alloc] init];
     }
+    if (flushQueueSize < 1 || flushQueueSize > 100) {
+        return self;
+    }
     config.flushQueueSize = flushQueueSize;
     return self;
 }

Sources/Classes/RSFlushManager.m

@@ -60,16 +60,18 @@ - (void)flushSync {
             batchDBMessage.messageIds = messageIds;
             batchDBMessage.messages = messages;
             NSString* payload = [RSCloudModeManager getPayloadFromMessages:batchDBMessage];
-            RSNetworkResponse* response = [self->networkManager sendNetworkRequest:payload toEndpoint:BATCH_ENDPOINT withRequestMethod:POST];
-            if( response.state == NETWORK_SUCCESS){
-                [RSLogger logDebug:[[NSString alloc] initWithFormat:@"RSFlushUtils: flushSync: Successfully sent batch %d/%d", i, numberOfBatches]];
-                [RSLogger logDebug:[[NSString alloc] initWithFormat:@"RSFlushUtils: flushSync: Clearing events of batch %d from DB", i]];
-                [self->dbPersistentManager updateEventsWithIds:batchDBMessage.messageIds withStatus:CLOUD_MODE_PROCESSING_DONE];
-                [self->dbPersistentManager clearProcessedEventsFromDB];
-                [_dbMessage.messages removeObjectsInArray:messages];
-                [_dbMessage.messageIds removeObjectsInArray:messageIds];
-                lastBatchFailed = NO;
-                break;
+            if (payload != nil) {
+                RSNetworkResponse* response = [self->networkManager sendNetworkRequest:payload toEndpoint:BATCH_ENDPOINT withRequestMethod:POST];
+                if( response.state == NETWORK_SUCCESS){
+                    [RSLogger logDebug:[[NSString alloc] initWithFormat:@"RSFlushUtils: flushSync: Successfully sent batch %d/%d", i, numberOfBatches]];
+                    [RSLogger logDebug:[[NSString alloc] initWithFormat:@"RSFlushUtils: flushSync: Clearing events of batch %d from DB", i]];
+                    [self->dbPersistentManager updateEventsWithIds:batchDBMessage.messageIds withStatus:CLOUD_MODE_PROCESSING_DONE];
+                    [self->dbPersistentManager clearProcessedEventsFromDB];
+                    [_dbMessage.messages removeObjectsInArray:messages];
+                    [_dbMessage.messageIds removeObjectsInArray:messageIds];
+                    lastBatchFailed = NO;
+                    break;
+                }
             }
             [RSLogger logDebug:[[NSString alloc] initWithFormat:@"RSFlushUtils: flushSync: Failed to send %d/%d, retrying again, %d retries left", i, numberOfBatches, retries]];
         }

Sources/Classes/RSUtils.m

@@ -240,6 +240,14 @@ + (BOOL) isApplicationUpdated {
     return (previousVersion && ![previousVersion isEqualToString:currentVersion]);
 }
 
++ (BOOL) isDBMessageEmpty:(RSDBMessage*)dbMessage {
+    return ([dbMessage.messages count] == 0 || [dbMessage.messageIds count] == 0);
+}
+
++ (BOOL) isEmptyString:(NSString*)value {
+    return (value == nil || value.length == 0);
+}
+
 unsigned int MAX_EVENT_SIZE = 32 * 1024; // 32 KB
 unsigned int MAX_BATCH_SIZE = 500 * 1024; // 500 KB