因此，我的目标是在用户删除其帐户时，如果已购买机票的客人人数超过 1，则删除所有用户的客人。
目前我有这个功能来尝试完成这个：
func deleteUserGuests(completion: @escaping (_ done: Bool) -> Void) {
var retries = 0
guard let user = Auth.auth().currentUser else { return }
func checkForGuestsAndDeleteIfAny() {
db.collection("student_users/\(user.uid)/events_bought").getDocuments { (querySnapshot, error) in
if let snapshot = querySnapshot {
if snapshot.isEmpty {
completion(true)
// done, nothing left to delete
} else {
// delete the documents using a dispatch group or a Firestore batch delete
for document in querySnapshot!.documents {
let docID = document.documentID
self.db.collection("student_users/\(user.uid)/events_bought/\(docID)/guests").getDocuments { (querySnap, error) in
guard querySnap?.isEmpty == false else {
print("The user being deleted has no guests with his purchases.")
return
}
let group = DispatchGroup()
for doc in querySnap!.documents {
let guest = doc.documentID
group.enter()
self.db.document("student_users/\(user.uid)/events_bought/\(docID)/guests/\(guest)").delete { (error) in
guard error == nil else {
print("Error deleting guests while deleting user.")
return
}
print("Guests deleted while deleting user!")
group.leave()
}
}
}
}
checkForGuestsAndDeleteIfAny()// call task again when this finishes
// because this function only exits when there is nothing left to delete
// or there have been too many failed attempts
}
} else {
if let error = error {
print(error)
}
retries += 1 // increment retries
run() // retry
}
}
}
func run() {
guard retries < 30 else {
completion(false) // 5 failed attempts, exit function
return
}
if retries == 0 {
checkForGuestsAndDeleteIfAny()
} else { // the more failures, the longer we wait until retrying
DispatchQueue.main.asyncAfter(deadline: .now() + Double(retries)) {
checkForGuestsAndDeleteIfAny()
}
}
}
run()
}
我提高了重试限制，看看是否是问题所在，但如果有多个客人，它仍然不会删除客人。
当用户在删除其帐户之前成功重新验证时，我会在警报操作中调用它：
let deleteAction = UIAlertAction(title: "Delete", style: .destructive) { (deletion) in
self.deleteButton.isHidden = true
self.loadingToDelete.alpha = 1
self.loadingToDelete.startAnimating()
self.deleteUserGuests { (response) in
if response == false {
return
}
}
self.deleteUserPurchases { (purchase) in
if purchase == false {
return
}
}
self.deleteUserOutOfFirestore { (removed) in
if removed == false {
return
}
}
user.delete(completion: { (error) in
guard error == nil else {
print("There was an error deleting user from the system.")
return
}
print("User Deleted.")
})
self.loadingToDelete.stopAnimating()
self.performSegue(withIdentifier: Constants.Segues.studentUserDeletedAccount, sender: self)
}
这是数据库中的结果：
其他所有内容都会按照正确的顺序、购买、用户本身以及 Firebase 身份验证中的用户被删除，但如果超过 1 位客人，客人永远不会被删除。deleteUserGuests导致此问题的方法中是否有我做错或遗漏的事情？