Splitting up Firebase Snapshots into smaller pieces? - swift

Question

For testing purposes, I created a specific node on my Firebase database. I copy a user over to that node and then can futz with it without worrying about corrupting data or ruining a user's info. It works really well for my purposes.
I've run into a problem, however. If a user has an extremely large set of data, the copy function won't work. It just stalls. I don't get any errors, though. I read that Firebase has copy limits of 1MB, and I'm guessing that's the problem. I'm running up against that wall, I think.
Here is my code:
func copyToTestingNode() {
let start = Date()
// 1 . create copy of user and then modify the copy
guard var copiedUser = user else { print("copied user error"); return }
copiedUser.userID = MP.adminID
copiedUser.householdInfo.subscriptionExpiryDate = 2500000000
// 2. get a snapshot of the copied user's info
ref.child(user.userID).observeSingleEvent(of: .value) { (userSnapshot) in
print("Step 2 TRT:", Date().timeIntervalSince(start))
// 3. remove any existing data at admin node, and then...
self.ref.child(MP.adminID).removeValue { (error, dbRef) in
print("Step 3 TRT:", Date().timeIntervalSince(start))
// 4. ...copy the new user info to the admin node
self.ref.child(MP.adminID).setValue(userSnapshot.value, withCompletionBlock: { (error, adminRef) in
print("Step 4 TRT:", Date().timeIntervalSince(start))
// 5. then send user alert and stop activity indicator
self.activityIndicator.stopAnimating()
self.showSimpleAlert(alertTitle: "Copy Complete", alertMessage: "Your copy of \(copiedUser.householdInfo.userName) is complete and can be found under the new node:\n\n\(copiedUser.householdInfo.userName) Family")
})
}
}
}
Options:
Is there a simple way to check the size of the DataSnapshot to alert me that the dataset is too large to copy over?
Is there a simple way to split up the snapshot into smaller pieces and overcome the 1MB limit that way?
Should I use Cloud Functions instead of trying to trigger this on a device?
Is there a way to somehow "compress" the snapshot to be smaller so that I can copy it easier?
I'm open to suggestions.
UPDATE #1
I read about the size limitation HERE. Judging from Frank's reaction, I'm guessing my understanding of that limitation is wrong.
I downloaded the node from the Firebase console and checked its size. It's 799 KB on my hard drive. It's a large JSON tree, and so I thought that its size must be the reason why it won't copy over. The smaller nodes copy over no problem. Just the large ones have trouble.
UPDATE #2
I'm not sure how to show the actual data, other than a screenshot, seeing how large the JSON tree is. So here is a screenshot:
As you can see, the data has multiple nodes, some of which are larger than others. I suppose I can cut down the 'Job Jar' node, but the rest really need to be that size for everything to work properly.
Granted, this is one of the largest datasets I have among all my users, but the structure doesn't change.
As for the speed of execution for each line of code, here are the simulator times for each numbered step:
Step 2 TRT: 0.5278879404067993
Step 3 TRT: 0.6249579191207886
Step 4 TRT: 1.8466829061508179
ALL DONE COPYING!!
This only works for the smaller datasets. For the larger ones, I never get to step 4. It just hangs. I let it run for several minutes, but no change.

Answer 1

Final version that seems to work:
func copyToTestingNode() {
// 1 . create copy of user and then modify the copy
guard var copiedUser = user else { print("copied user error"); return }
let adminRef = ref.child(MP.adminID)
copiedUser.userID = MP.adminID
copiedUser.householdInfo.subscriptionExpiryDate = 2500000000
// 2. get a snapshot of the copied user's info
ref.child(user.userID).observeSingleEvent(of: .value) { (userSnapshot) in
// 3. remove any existing data at admin node, and then...
adminRef.removeValue { (error, dbRef) in
if (error != nil) { print("Yikes!") }
// 4. ...copy the new user info to the admin node one node at a time (if user has a lot of data)
var totalNodesCopied = 0
for item in userSnapshot.children {
guard let snap = item as? DataSnapshot else { print("snap error"); return }
self.ref.child(MP.adminID).child(snap.key).setValue(snap.value) { (error, adminRef) in
totalNodesCopied += 1
if totalNodesCopied == userSnapshot.childrenCount {
print("ALL DONE COPYING!!")
}
}
}
}
}
}