Offline storage to file system on failed upload

Agent.xcodeproj/project.pbxproj

@@ -1034,6 +1034,8 @@
 		F824A43129AEAD63000886A6 /* NRViewModifier.swift in Sources */ = {isa = PBXBuildFile; fileRef = F824A43029AEAD63000886A6 /* NRViewModifier.swift */; };
 		F824A43229AEAD63000886A6 /* NRViewModifier.swift in Sources */ = {isa = PBXBuildFile; fileRef = F824A43029AEAD63000886A6 /* NRViewModifier.swift */; };
 		F825FAE329C8F52800E1C1DC /* NRMAWKFakeNavigationAction.m in Sources */ = {isa = PBXBuildFile; fileRef = F825FAE229C8F52800E1C1DC /* NRMAWKFakeNavigationAction.m */; };
+		F83A77B02B48810900B3D180 /* NRMAOfflineStorageTests.m in Sources */ = {isa = PBXBuildFile; fileRef = F83A77AF2B48810900B3D180 /* NRMAOfflineStorageTests.m */; };
+		F83A77B12B48810900B3D180 /* NRMAOfflineStorageTests.m in Sources */ = {isa = PBXBuildFile; fileRef = F83A77AF2B48810900B3D180 /* NRMAOfflineStorageTests.m */; };
 		F848CDC02AA133EA0082052F /* NRMAInteractionEvent.m in Sources */ = {isa = PBXBuildFile; fileRef = F848CDBF2AA133EA0082052F /* NRMAInteractionEvent.m */; };
 		F848CDC12AA133EA0082052F /* NRMAInteractionEvent.m in Sources */ = {isa = PBXBuildFile; fileRef = F848CDBF2AA133EA0082052F /* NRMAInteractionEvent.m */; };
 		F858F3602AE04B0C00CF9EB5 /* NRMAURLSessionHeaderTrackingTests.m in Sources */ = {isa = PBXBuildFile; fileRef = F858F35F2AE04B0C00CF9EB5 /* NRMAURLSessionHeaderTrackingTests.m */; };
@@ -1046,6 +1048,8 @@
 		F8A455492AFBE31E0057B1E0 /* NRMAURLSessionHeaderTrackingTestsOldEventSystem.m in Sources */ = {isa = PBXBuildFile; fileRef = F8A455472AFBE31E0057B1E0 /* NRMAURLSessionHeaderTrackingTestsOldEventSystem.m */; };
 		F8AC3E932938FD6C002B4AA8 /* NRMAFakeDataHelper.m in Sources */ = {isa = PBXBuildFile; fileRef = F8AC3E922938FD6C002B4AA8 /* NRMAFakeDataHelper.m */; };
 		F8AC3E942938FD6C002B4AA8 /* NRMAFakeDataHelper.m in Sources */ = {isa = PBXBuildFile; fileRef = F8AC3E922938FD6C002B4AA8 /* NRMAFakeDataHelper.m */; };
+		F8E202DE2B07BA61008E0B7B /* NRMAOfflineStorage.m in Sources */ = {isa = PBXBuildFile; fileRef = F8E202DD2B07BA61008E0B7B /* NRMAOfflineStorage.m */; };
+		F8E202DF2B07BA61008E0B7B /* NRMAOfflineStorage.m in Sources */ = {isa = PBXBuildFile; fileRef = F8E202DD2B07BA61008E0B7B /* NRMAOfflineStorage.m */; };
 		F8FBFA512A71ACB200CDC8C5 /* NRMARequestEvent.m in Sources */ = {isa = PBXBuildFile; fileRef = F8FBFA502A71ACB200CDC8C5 /* NRMARequestEvent.m */; };
 		F8FBFA522A71ACB200CDC8C5 /* NRMARequestEvent.m in Sources */ = {isa = PBXBuildFile; fileRef = F8FBFA502A71ACB200CDC8C5 /* NRMARequestEvent.m */; };
 		F8FBFA552A71BA2900CDC8C5 /* NRMAPayload.m in Sources */ = {isa = PBXBuildFile; fileRef = F8FBFA542A71BA2900CDC8C5 /* NRMAPayload.m */; };
@@ -1957,6 +1961,7 @@
 		F824A43029AEAD63000886A6 /* NRViewModifier.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = NRViewModifier.swift; sourceTree = "<group>"; };
 		F825FAE229C8F52800E1C1DC /* NRMAWKFakeNavigationAction.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMAWKFakeNavigationAction.m; sourceTree = "<group>"; };
 		F825FAF729C8F5BA00E1C1DC /* NRMAWKFakeNavigationAction.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = NRMAWKFakeNavigationAction.h; sourceTree = "<group>"; };
+		F83A77AF2B48810900B3D180 /* NRMAOfflineStorageTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMAOfflineStorageTests.m; sourceTree = "<group>"; };
 		F848CDBF2AA133EA0082052F /* NRMAInteractionEvent.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMAInteractionEvent.m; sourceTree = "<group>"; };
 		F848CDD52AA133FB0082052F /* NRMAInteractionEvent.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = NRMAInteractionEvent.h; sourceTree = "<group>"; };
 		F858F35F2AE04B0C00CF9EB5 /* NRMAURLSessionHeaderTrackingTests.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMAURLSessionHeaderTrackingTests.m; sourceTree = "<group>"; };
@@ -1966,6 +1971,8 @@
 		F8A455472AFBE31E0057B1E0 /* NRMAURLSessionHeaderTrackingTestsOldEventSystem.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMAURLSessionHeaderTrackingTestsOldEventSystem.m; sourceTree = "<group>"; };
 		F8AC3E922938FD6C002B4AA8 /* NRMAFakeDataHelper.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMAFakeDataHelper.m; sourceTree = "<group>"; };
 		F8AC3EA72938FDDB002B4AA8 /* NRMAFakeDataHelper.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = NRMAFakeDataHelper.h; sourceTree = "<group>"; };
+		F8E202DD2B07BA61008E0B7B /* NRMAOfflineStorage.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMAOfflineStorage.m; sourceTree = "<group>"; };
+		F8E202F32B07BA6E008E0B7B /* NRMAOfflineStorage.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = NRMAOfflineStorage.h; sourceTree = "<group>"; };
 		F8FBFA502A71ACB200CDC8C5 /* NRMARequestEvent.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMARequestEvent.m; sourceTree = "<group>"; };
 		F8FBFA532A71ACC000CDC8C5 /* NRMARequestEvent.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = NRMARequestEvent.h; sourceTree = "<group>"; };
 		F8FBFA542A71BA2900CDC8C5 /* NRMAPayload.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = NRMAPayload.m; sourceTree = "<group>"; };
@@ -2376,6 +2383,7 @@
 				F8AC3E922938FD6C002B4AA8 /* NRMAFakeDataHelper.m */,
 				F8AC3EA72938FDDB002B4AA8 /* NRMAFakeDataHelper.h */,
 				2B4226E529DB99740068BB8A /* NRMAHTTPUtilitiesTests.m */,
+				F83A77AF2B48810900B3D180 /* NRMAOfflineStorageTests.m */,
 			);
 			path = Uncategorized;
 			sourceTree = "<group>";
@@ -3126,6 +3134,8 @@
 				02FF4A8424DC652C00115469 /* NRMAMemoryVitals.m */,
 				02FF4A8624DC652C00115469 /* NRMANonARCMethods.h */,
 				02FF4A8524DC652C00115469 /* NRMANonARCMethods.m */,
+				F8E202F32B07BA6E008E0B7B /* NRMAOfflineStorage.h */,
+				F8E202DD2B07BA61008E0B7B /* NRMAOfflineStorage.m */,
 				02FF4A8324DC652C00115469 /* NRMAUDIDManager.h */,
 				02FF4A8D24DC652D00115469 /* NRMAUDIDManager.m */,
 				02FF4A8B24DC652D00115469 /* NRMAUUIDStore.h */,
@@ -4334,6 +4344,7 @@
 				0209AC1224E7071500E45C90 /* NRMAAPIHelperTests.m in Sources */,
 				0209AC4524E7078000E45C90 /* NRMAFeatureFlagsTests.m in Sources */,
 				2B02DB86293E630B001A59D6 /* NRMAURLSessionAsyncTests.swift in Sources */,
+				F83A77B02B48810900B3D180 /* NRMAOfflineStorageTests.m in Sources */,
 				0209AC3224E7073800E45C90 /* NRMAHarvestableAnalyticsTest.m in Sources */,
 				0209AC9924E7393300E45C90 /* NSURLConnectionTests.m in Sources */,
 				0209ABFE24E7070900E45C90 /* NRURLSessionDelegateTests.m in Sources */,
@@ -4492,6 +4503,7 @@
 				02FF4A2324DC648600115469 /* NRMAMeasurementConsumer.m in Sources */,
 				02FF4AA824DC652E00115469 /* NRMAUDIDManager.m in Sources */,
 				02FF48DC24DC622700115469 /* NRMACrashDataUploader.m in Sources */,
+				F8E202DE2B07BA61008E0B7B /* NRMAOfflineStorage.m in Sources */,
 				02FF49E824DC644900115469 /* NRMAKeyAttributes.m in Sources */,
 				02FF49EF24DC645B00115469 /* NRMAAppInstallMetricGenerator.m in Sources */,
 				02FF4A7724DC64FC00115469 /* NRTimer.m in Sources */,
@@ -4583,6 +4595,7 @@
 				025657F924EB19BF00FE3125 /* NSURLSessionOverrideTest.m in Sources */,
 				F8AC3E942938FD6C002B4AA8 /* NRMAFakeDataHelper.m in Sources */,
 				025657FA24EB19BF00FE3125 /* NRActivityTracesTest.m in Sources */,
+				F83A77B12B48810900B3D180 /* NRMAOfflineStorageTests.m in Sources */,
 				025657FB24EB19BF00FE3125 /* NRMeasurementTest.m in Sources */,
 				2B40F4FF28BEB95E00EAD248 /* NRMAStartTimerTests.m in Sources */,
 				025657FC24EB19BF00FE3125 /* TestUITableViewInstrumentation.m in Sources */,
@@ -4725,6 +4738,7 @@
 				2B33E5D32AA9160E00AEB7B4 /* NRMASessionEvent.m in Sources */,
 				F8FBFA632A78416300CDC8C5 /* NRMAMobileEvent.m in Sources */,
 				02FF4C0524E3201400115469 /* NRMAMetric.m in Sources */,
+				F8E202DF2B07BA61008E0B7B /* NRMAOfflineStorage.m in Sources */,
 				02FF4C0624E3201400115469 /* NRMAInteractionHistory.c in Sources */,
 				02FF4C0724E3201400115469 /* NRMAActivityNameGenerator.m in Sources */,
 				02FF4C0824E3201400115469 /* NRMAScopedMeasurement.m in Sources */,

Agent/Analytics/Constants.h

@@ -79,13 +79,15 @@ extern NSString *const kNRMA_Attrib_dtGuid;
 extern NSString *const kNRMA_Attrib_dtId;
 extern NSString *const kNRMA_Attrib_dtTraceId;
 extern NSString *const kNRMA_Attrib_name;
+extern NSString *const kNRMA_Attrib_offline;
 
 extern NSString *const kNRMA_Val_errorType_HTTP;
 extern NSString *const kNRMA_Val_errorType_Network;
 
 extern NSString *const kNRMA_Attrib_file;
 extern NSString *const kNRMA_Attrib_file_private;
 
+extern NSString *const kNRMA_Offline_folder;
 
 // Integer Analytics Constants
 static int kNRMA_Attrib_Max_Name_Length = 256;

Agent/Analytics/Constants.m

@@ -84,10 +84,13 @@
 NSString * const kNRMA_Attrib_dtId              = @"id";
 NSString * const kNRMA_Attrib_dtTraceId         = @"trace.id";
 NSString * const kNRMA_Attrib_name              = @"name";
+NSString * const kNRMA_Attrib_offline           = @"offline";
 
 NSString * const kNRMA_Val_errorType_HTTP       = @"HTTPError";
 NSString * const kNRMA_Val_errorType_Network    = @"NetworkFailure";
 
 
 NSString * const kNRMA_Attrib_file       = @"attributes.txt";
 NSString * const kNRMA_Attrib_file_private    = @"privateAttributes.txt";
+
+NSString * const kNRMA_Offline_folder          = @"offlineStorage";

Agent/Analytics/Events/NRMAMobileEvent.m

@@ -56,7 +56,6 @@ - (id)JSONObject {
     dict[kNRMA_RA_timestamp] = @(self.timestamp);
     dict[kNRMA_RA_sessionElapsedTime] = @(self.sessionElapsedTimeSeconds);
     dict[kNRMA_RA_eventType] = self.eventType;
-
     return [NSDictionary dictionaryWithDictionary:dict];
 }
 

Agent/CrashHandler/NRMAExceptionHandlerManager.m

@@ -107,7 +107,13 @@ - (instancetype) initWithLastSessionsAttributes:(NSDictionary*)attributes
             [_reportManager processReportsWithSessionAttributes:attributes
                                                 analyticsEvents:events];
 
-            [self.uploader uploadCrashReports];
+            NRMAReachability* r = [NewRelicInternalUtils reachability];
+            @synchronized(r) {
+                NRMANetworkStatus status = [r currentReachabilityStatus];
+                if (status != NotReachable) { // Because we support offline mode check if we're online before sending the crash reports
+                    [self.uploader uploadCrashReports];
+                }
+            }
         }
 
         self.handler = [[NRMAUncaughtExceptionHandler alloc] initWithCrashReporter:_crashReporter];

Agent/FeatureFlags/NRMAFlags.h

@@ -49,6 +49,8 @@
 
 + (BOOL) shouldEnableLogReporting;
 
++ (BOOL) shouldEnableOfflineStorage;
+
 + (BOOL) shouldEnableNewEventSystem;
 
 + (NSArray<NSString*>*) namesForFlags:(NRMAFeatureFlags)flags;

Agent/FeatureFlags/NRMAFlags.m

@@ -47,7 +47,8 @@ + (NRMAFeatureFlags) featureFlags
                               NRFeatureFlag_NetworkRequestEvents | 
                               NRFeatureFlag_RequestErrorEvents |
                               NRFeatureFlag_DistributedTracing |
-                              NRFeatureFlag_AppStartMetrics;
+                              NRFeatureFlag_AppStartMetrics |
+                              NRFeatureFlag_OfflineStorage;
                   });
     return __flags;
 }
@@ -161,6 +162,11 @@ + (BOOL) shouldEnableFedRampSupport {
 + (BOOL) shouldEnableSwiftAsyncURLSessionSupport {
     return ([NRMAFlags featureFlags] & NRFeatureFlag_SwiftAsyncURLSessionSupport) != 0;
 }
+
++ (BOOL) shouldEnableOfflineStorage {
+    return ([NRMAFlags featureFlags] & NRFeatureFlag_OfflineStorage) != 0;
+}
+
 + (BOOL) shouldEnableLogReporting {
     return NO;
     //return ([NRMAFlags featureFlags] & NRFeatureFlag_LogReporting) != 0;
@@ -218,6 +224,9 @@ + (BOOL) shouldEnableNewEventSystem {
     if ((flags & NRFeatureFlag_SwiftAsyncURLSessionSupport) == NRFeatureFlag_SwiftAsyncURLSessionSupport) {
         [retArray addObject:@"SwiftAsyncURLSessionSupport"];
     }
+    if ((flags & NRFeatureFlag_OfflineStorage) == NRFeatureFlag_OfflineStorage) {
+        [retArray addObject:@"OfflineStorage"];
+    }
 
     // NOTE: Temporarily removed NRFeatureFlag_LogReporting
 //    if ((flags & NRFeatureFlag_LogReporting) == NRFeatureFlag_LogReporting) {

Agent/General/NewRelicAgentInternal.m

@@ -475,15 +475,22 @@ - (void) onSessionStart {
 
     // Initializing analytics take a while. Take care executing time sensitive code after this point the since initializeAnalytics method will delay its execution.
     [self initializeAnalytics];
-
+    NRMAReachability* r = [NewRelicInternalUtils reachability];
+    NRMANetworkStatus status;
+    @synchronized(r) {
+        status = [r currentReachabilityStatus];
+    }
     if ([NRMAFlags shouldEnableHandledExceptionEvents]) {
         self.handledExceptionsController = [[NRMAHandledExceptions alloc] initWithAnalyticsController:self.analyticsController
                                                                                      sessionStartTime:self.appSessionStartDate
                                                                                    agentConfiguration:self.agentConfiguration
                                                                                              platform:[NewRelicInternalUtils osName]
                                                                                             sessionId:[self currentSessionId]];
 
-        [self.handledExceptionsController processAndPublishPersistedReports];
+
+        if (status != NotReachable) { // Because we support offline mode check if we're online before sending the handled exceptions
+            [self.handledExceptionsController processAndPublishPersistedReports];
+        }
 
         [NRMAHarvestController addHarvestListener:self.handledExceptionsController];
 
@@ -493,8 +500,9 @@ - (void) onSessionStart {
 
     // Attempt to upload crash report files (if any exist)
     if ([NRMAFlags shouldEnableCrashReporting]) {
-
-        [[NRMAExceptionHandlerManager manager].uploader uploadCrashReports];
+        if (status != NotReachable) { // Because we support offline mode check if we're online before sending the crash reports
+            [[NRMAExceptionHandlerManager manager].uploader uploadCrashReports];
+        }
     }
 
     if([NRMAFlags shouldEnableGestureInstrumentation])

Agent/HandledException/NRMAHandledExceptions.mm

@@ -131,9 +131,21 @@ - (instancetype) initWithAnalyticsController:(NRMAAnalytics*)analytics
 }
 
 - (void) onHarvest {
-    _controller->publish();
-    _store->clear();
-    _publisher->retry();
+    if([NRMAFlags shouldEnableOfflineStorage]) {
+        NRMAReachability* r = [NewRelicInternalUtils reachability];
+        @synchronized(r) {
+            NRMANetworkStatus status = [r currentReachabilityStatus];
+            if (status != NotReachable) {
+                [self processAndPublishPersistedReports]; // When using offline we always want to send from persisted because the keyContext doesn't persist.
+                _controller->resetKeyContext();
+                _publisher->retry();
+            }
+        }
+    } else {
+        _controller->publish();
+        _store->clear();
+        _publisher->retry();
+    }
 }
 
 - (fbs::Platform) fbsPlatformFromString:(NSString*)platform {

Agent/HandledException/NRMAHexUploader.m

@@ -11,9 +11,9 @@
 #import "NRLogger.h"
 #include <libkern/OSAtomic.h>
 #import "NRMASupportMetricHelper.h"
+#import "NRConstants.h"
 
 #define kNRMARetryLimit 2 // this will result in 2 additional upload attempts.
-#define kNRMAMaxPayloadSizeLimit 1000000
 
 @interface NRMAHexUploader()
 @property(strong) NSString* host;

Agent/Harvester/DataStore/NRMAAgentConfiguration.h

@@ -44,4 +44,7 @@
 + (void) setMaxEventBufferTime:(NSUInteger)seconds;
 + (NSUInteger) getMaxEventBufferTime;
 
++ (void) setMaxOfflineStorageSize:(NSUInteger)megaBytes;
++ (NSUInteger) getMaxOfflineStorageSize;
+
 @end

Agent/Harvester/DataStore/NRMAAgentConfiguration.m

@@ -22,6 +22,7 @@
 
 // Default max event buffer time is 10 minutes (600 seconds).
 static NSUInteger __NRMA__maxEventBufferTime = 600;
+static NSUInteger __NRMA__maxOfflineStorageSize = 100000000; // 100 mb
 
 @implementation NRMAAgentConfiguration
 
@@ -49,6 +50,14 @@ + (NSUInteger) getMaxEventBufferTime {
     return __NRMA__maxEventBufferTime;
 }
 
++ (void) setMaxOfflineStorageSize:(NSUInteger)megaBytes {
+    __NRMA__maxOfflineStorageSize = megaBytes;
+}
+
++ (NSUInteger) getMaxOfflineStorageSize {
+    return __NRMA__maxOfflineStorageSize;
+}
+
 - (id) initWithAppToken:(NRMAAppToken*)token
        collectorAddress:(NSString*)collectorHost
            crashAddress:(NSString*)crashHost {

Agent/Harvester/NRMAHarvestController.h

@@ -40,6 +40,8 @@
 
 + (BOOL) shouldNotCollectTraces;
 
++ (void) setMaxOfflineStorageSize:(NSUInteger) size;
+
 #pragma mark - HarvestController interface
 
 + (NRMAHarvesterConfiguration*) configuration;

Agent/Harvester/NRMAHarvestController.m

@@ -317,6 +317,10 @@ + (void) addHarvestableActivity:(NRMAHarvestableActivity*)activity
         [harvestData.activityTraces addActivityTraces:activity];
     }
 }
+
++ (void) setMaxOfflineStorageSize:(NSUInteger) size {
+    [[[NRMAHarvestController harvestController] harvester] setMaxOfflineStorageSize:size];
+}
 @end
 
 #ifdef __cplusplus

Agent/Harvester/NRMAHarvester.h

@@ -67,6 +67,8 @@ typedef enum {
 - (void) removeHarvestAwareObject:(id<NRMAHarvestAware>)harvestAware;
 - (void) fireOnHarvestStart;
 - (void) stop;
+
+- (void) setMaxOfflineStorageSize:(NSUInteger) size;
 @end
 
 #ifdef __cplusplus

Agent/Harvester/NRMAHarvester.mm

@@ -20,6 +20,7 @@
 #include <Utilities/Application.hpp>
 #import "NRMASupportMetricHelper.h"
 #import "NRMAFlags.h"
+#import "Constants.h"
 
 #define kNRSupportabilityResponseCode kNRSupportabilityPrefix @"/Collector/ResponseStatusCodes"
 
@@ -333,13 +334,20 @@ - (void) connected
     //TODO: add addition collector response processing.
     if (response.isError) {
         // failure
-        [self fireOnHarvestFailure];
+        if([self checkOfflineAndPersist:response]) {
+            // If the harvest was persisted for offline storage clear the harvest.
+            [self.harvestData clear];
+        } else {
+            [self fireOnHarvestFailure];
+        }
     } else {
         // success
         [self.harvestData clear];
+        // If there was a successful harvest upload send the persisted offline payloads.
+        [connection sendOfflineStorage];
     }
     //Supportability/MobileAgent/Collector/Harvest
-    
+
     [harvestTimer stopTimer];
 #ifndef  DISABLE_NRMA_EXCEPTION_WRAPPER
     @try {
@@ -357,6 +365,28 @@ - (void) connected
     [self fireOnHarvestComplete];
 }
 
+- (BOOL) checkOfflineAndPersist:(NRMAHarvestResponse*) response {
+    if (![NRMAFlags shouldEnableOfflineStorage]) {
+        return false;
+    }
+    if([NRMAOfflineStorage checkErrorToPersist:response.error]) {
+        NSMutableDictionary *tempAnalyticsAttributes = [[NSMutableDictionary alloc] initWithDictionary:self.harvestData.analyticsAttributes];
+        if(tempAnalyticsAttributes.count > 0){
+            [tempAnalyticsAttributes setValue:[NSNumber numberWithBool:YES] forKey:kNRMA_Attrib_offline];
+            [self.harvestData setAnalyticsAttributes:[[NSDictionary alloc] initWithDictionary:tempAnalyticsAttributes]];
+        }
+        NSError* error = nil;
+        NSData* jsonData = [NRMAJSON dataWithJSONABLEObject:self.harvestData options:0 error:&error];
+        if (error) {
+            NRLOG_ERROR(@"Failed to generate JSON");
+            return false;
+        }
+        [connection.offlineStorage persistDataToDisk:jsonData];
+        return true;
+    }
+    return false;
+}
+
 - (void) disconnected
 {
     // Handle stored config.
@@ -696,4 +726,8 @@ - (void) stop
     }
 }
 
+- (void) setMaxOfflineStorageSize:(NSUInteger) size {
+    [connection setMaxOfflineStorageSize:size];
+}
+
 @end