iOS: Make a queue of http requests in offline - ios

Question

I have an application that works with the server.
I would like to make an offline mode that is when a user creates something or changes it was saved somewhere and then when an internet connection appears - these requests go to the server. How can I achieve this? How to store blocks in NSUserDefaults? How not to lose pointers to these blocks?
It can be different controllers. Help me please. I apologize for my bad English.
I've tried to save this objects in NSUserDefaults
typedef void (^ExecutionBlock)(void);
#interface OfflineBlockObject : NSObject
#property (nonatomic, copy) ExecutionBlock block;
#property (nonatomic, strong) NSArray<NSMutableArray *> *operandsArray;
#property (nonatomic, strong) NSArray *conditionsArray;
#end
OfflineBlockObject *blockObject = [[OfflineBlockObject alloc] init];
BOOL first = [self.reservation.reservationID boolValue];
NSArray *conditions = #[#(first), #(self.shouldCallSetTagsForReservation)];
NSArray *operands = #[#[[self.reservation json], self.reservation.reservationID ? : #0, self.selectedTags ? : #[]],
#[[self.reservation json], #(self.shouldForceApproved), self.selectedTags? : #[]]];
blockObject.conditionsArray = [conditions copy];
blockObject.operandsArray = [operands copy];
#weakify(blockObject);
blockObject.block = [^{
#strongify(blockObject);
if ([blockObject.conditionsArray[0] boolValue]) {
ReservationsModel *m = [[ReservationsModel alloc] init];
[m editReservation:blockObject.operandsArray[0][0] success:^(id responseObject) {
if ([blockObject.conditionsArray[1] boolValue]) {
[m setReservationTags:blockObject.operandsArray[0][1] tags:blockObject.operandsArray[0][2] success:nil failure:nil];
}
} failure:nil];
} else {
self.reservation.eventId = self.reservationEvent.eventInfoID;
ReservationsModel *m = [[ReservationsModel alloc] init];
[m createReservation:blockObject.operandsArray[1][0] shouldForceApproved:[blockObject.operandsArray[1][1] boolValue] success:^(id responseObject) {
Reservation *reservation = [Reservation reservationWithJson:responseObject];
if (reservation.reservationID) {
if ([blockObject.conditionsArray[1] boolValue]) {
[m setReservationTags:reservation.reservationID tags:blockObject.operandsArray[0][2] success:nil failure:nil];
}
}
} failure:nil];
}
} copy];
[[OfflineQueueHelper sharedHelper] addTask:blockObject];
But my block property becomes null :(

Answer 1

So I have a pod that does pretty much this, but it's in Swift (the Obj-C made the interface too convoluted) - https://cocoapods.org/pods/OfflineRequestManager. You can make any object that conforms to OfflineRequest that wraps whatever network request you want to make it to the server. You can also provide a dictionary that gets written to disk if you want to make sure that it persists through app termination. We've been using it in our internal apps for a while now, so hopefully somebody else can get some use out of it.
The simplest use case would look something like the following, though most actual cases (saving to disk, specific request data, etc.) will have a few more hoops to jump through:
import OfflineRequestManager
class SimpleRequest: OfflineRequest {
func perform(completion: #escaping (Error?) -> Void) {
doMyNetworkRequest(withCompletion: { response, error in
handleResponse(response)
completion(error)
})
}
}
///////
OfflineRequestManager.defaultManager(queueRequest: SimpleRequest())