I enter и leave dispatchGroup без проблем, когда мое приложение запускается изначально, оно разрывается при изменении узла user в Firebase.
Как эффективно обработать dispatchGroup?
//Gets all Invites received for a user
func getInvitesReceived(forUserId forId: String, handler: @escaping ([[String : Any]], Bool) -> ()){
getInvitesReceivedHandle = REF_USERS_INVITES.child(forId).observe(.value) { (snapshot) in
var invites = [[String : Any]]()//empty array to hold Invites
let dispatchGroup = DispatchGroup()//To track and get notified when the execution has finished before proceeding
for item in snapshot.children{ //looping through snapshot made up of sender $uid nodes
let itemSnap = item as! DataSnapshot
let fromId = itemSnap.key //getting the $uid from the snapshot key
let dict = itemSnap.value as! [String : Bool] //getting the child nodes from each sender as dictionary to loop through
for (key, status) in dict { //loop throuch each dictionary made up of compliment_id : status
switch status {//check status
case true:
dispatchGroup.enter()
//Using helper function to get `User` info by passing `fromId`
self.getUserInfo(forUserId: fromId, handler: { (user) in
var timeStamp: Int?
//Using helper function to get `Compliment` info by passing key = complimentId
self.getInviteInfo(forInvitetId: key, handler: { (inviteDict) in
timeStamp = inviteDict["timeStamp"] as? Int
let invitePack = [
"type": "invite",
"complimentId": key,
"status": status,
"timeStamp": timeStamp!,
"fromUser": user
] as [String : Any]
invites.append(invitePack)
dispatchGroup.leave()
})//getComplimentInfo
})//end getUserInfo
case false:
break
}//end switch
}//end for dict
}//end for snapshot.item
//get notified of completion then execute handler
dispatchGroup.notify(queue: .main) {
handler(invites, true)
}//end dispatchGroup
}//end observe
}//end func
I observe пользовательский узел и сбой на dispatchGroup.leave() строке выше, когда есть изменение впользовательский узел.
func getUserInfo(forUserId forId: String, handler: @escaping (User) -> ()) {
REF_USERS.child(forId).observe(.value, with: { (snapshot) in
//..... handle snapshot
let user = User(uid: uid, dictionary: dictionary)
handler(user)
}) { (error) in
print(error.localizedDescription)
}
}//end func
Редактировать: структура Firebase читается
