ios - Firebase in Swift nested query not working properly

Question

I have a JSON structure like the following:

{
  "groups" : {
    "-KAv867tzVgIghmr15CM" : {
      "author" : "ruben",
      "name" : "Item A"
    },
    "-KAv87nqLEG1Jtc04Ebn" : {
      "author" : "ruben",
      "name" : "Item B"
    },
    "-KAv88yZe8KTfkjAE7In" : {
      "author" : "ruben",
      "name" : "Item C"
    }
  },
  "users" : {
    "rsenov : {
      "avatar" : "guest",
      "email" : "[email protected]",
      "groups" : {
        "-KAv867tzVgIghmr15CM" : "true",
        "-KAv87nqLEG1Jtc04Ebn" : "true",
        "-KAv88yZe8KTfkjAE7In" : "true"
      }
    }
  }
}

Every user has the element "groups" with a childByAutoId() key. Then I have the list of all the groups that exists in the app.

Every time that I run the app, I get the current user logged url reference, and I get the list of the groups of that user (in this case, the logged in user is "rsenov" that has 3 groups). For every group that this user belongs to, I iterate through the groups url reference, looking for getting the information of that 3 groups.

I do this like this:

func loadTable() {
    self.groups = []
    var counter = 0
    self.meses = []
    var tempItems = [String]()

    DataService.dataService.CURRENT_USER_GROUPS_REF.observeEventType(.Value, withBlock: { snapshot in

        if let snapshots = snapshot.children.allObjects as? [FDataSnapshot] {
            tempItems = []
            for snap in snapshots {

                DataService.dataService.GROUPS_REF.childByAppendingPath(snap.key).queryOrderedByChild("name").observeEventType(.Value, withBlock: { snapshot in
                    if let postDictionary = snapshot.value as? Dictionary<String, AnyObject> {
                        tempItems.append(snapshot.value.objectForKey("name") as! String)
                        let key = snapshot.key
                        let group = Group(key: key, dictionary: postDictionary)
                        self.groups.insert(group, atIndex: 0)

                    }
                    counter++
                    if (counter == snapshots.count) {
                        self.meses = tempItems
                        self.miTabla.reloadData()

                    }
                })
            }
        }
    })
}

I think this is not a good idea of iterating in that way. For example, if there is a change of some child in the GROUPS_REF url, the code only runs in that nested code, and since it doesn't have the "snap.key" value got from the for loop, it doesn't work.

Which is the best way to do a good query in this case?

Answer 1

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