Firebase how to make this kind of query in Swift - json

Question

I have this JSON structure:
{
"groups" : {
"-KBxo9-RoY0eowWKeHkU" : {
"author" : "rsenov",
"members" : {
"-KBxo7ZU6McsmDOxyias" : true,
"-KBxo8_TUTW6NZze6xcd" : true,
"rsenov" : true
},
"name" : "Prueba 3"
}
},
"users" : {
"-KBxo7ZU6McsmDOxyias" : {
"avatar" : "owl2",
"groups" : {
"-KBxo9-RoY0eowWKeHkU" : true
},
"isUser" : false,
"name" : "Pepa"
},
"-KBxo8_TUTW6NZze6xcd" : {
"avatar" : "monkey",
"groups" : {
"-KBxo9-RoY0eowWKeHkU" : true
},
"isUser" : false,
"name" : "Lolas"
},
"rsenov" : {
"avatar" : "guest",
"groups" : {
"-KBxo9-RoY0eowWKeHkU" : true
},
"isUser" : true,
"name" : "Ruben",
}
}
}
and the security&rules file is:
{
"rules": {
".read": true,
".write": true,
"users": {
".indexOn": ["email", "groups"]
},
"groups": {
".indexOn": ["author", "name"]
}
}
}
I'm trying to run a query in order to get the ChildChanged snapshot:
DataService.dataService.USERS_REF.queryOrderedByChild("groups").queryEqualToValue(currentGroup.groupKey).observeEventType(.ChildChanged, withBlock: {snapshot in
print(snapshot)
})
DataService.dataService.USERS_REFcorresponds to the url that point to the "users" key, and currentGroup.groupKeyis equal to -KBxo9-RoY0eowWKeHkUin this case.
According to this query, I should get the snapshot of the child that has changed. For example, if I replace the user name "Pepa" to "Test", I should get the snapshot:
"-KBxo7ZU6McsmDOxyias" : {
"avatar" : "owl2",
"groups" : {
"-KBxo9-RoY0eowWKeHkU" : true
},
"isUser" : false,
"name" : "Test"
}
but this query never get's called...
Is there something wrong in my query?

Answer 1

"I'm trying to run a query in order to get the ChildChanged snapshot:" is a little odd.
You can query for data, or observe a node via ChildChanged.
If you just want to be notified of changes within the users node, add an observer to that node and when Pepa changes to Test, your app will be notified and provided a snapshot of the user node that changed.
var ref = Firebase(DataService.dataService.USERS_REF)
ref.observeEventType(.ChildChanged, withBlock: { snapshot in
println("the changed user is: \(snapshot.value)")
})
Oh, and no need for queryOrderedByChild since the snapshot will only contain the single node that changed.