FirebaseDatabase query issues in Swift - ios

Question

So I am currently working on a clone like snapchat and I am sending pull requests to the server, but as for downloading, it is not going so well. I created a reference to the database that looks like this,
var recievers: FIRDatabaseReference{
return mainRef.child("pullRequests")
}
and then I have a viewController that parses the data (which I know isn't the best way to go about this but I'm just trying to get it working right now) and in there I have this
DataService.instance.recievers.observeSingleEvent(of: .value) {(recipients: FIRDataSnapshot) in
if let recipient = recipients.value as? Dictionary<String,AnyObject>{
var index = 0;
for(key,value) in recipient{
index = index+1
if let dict = value as? Dictionary<String,AnyObject>{
if let reciever = dict["recipents"] as? Dictionary<String,AnyObject>{
if let num = reciever["\(index)"] as? String{
let uid = num
recipientsArr.append(uid)
}
}
}
}
}
}
for i in 0...recipientsArr.count{
print(i)
}
I'm not getting any compiling errors but it is also not adding anything into the recipientsArr, can anyone help guide me in the right direction?
My Firebase looks like this:

Answer 1

You're not decoding the snapshot properly. Its unclear from your question what is the value event you want to observe - is it just a new recipient that was added? the whole pullRequest?
In any case you're observing the pullRequest reference and therefore in order to decode the snapshot:
if let pullRequest = recipients.value as? Dictionary<String,AnyObject>{
if let recipientsList = pullRequest["recipents"] as? Dictionary<String,AnyObject>{
for (_, value) in recipientsList {
if let uid = value as? String{
recipientsArr.append(uid)
}
}
}
}

Answer 2

The problem is that you are using the method observeSingleEvent to update the value in the database, when this method is only used to recieve data from the database, not updated. In other words, it read-only.
The way to update record in a firebase database works different than the read methods. You can use both methods setValue and updateChildValues to perform updates. They both work on a database reference.
To use the setValue method, you should do something like this. I'll assume that you already have a pullRequests object that you previously created from the information you fetched from the database and have it in a variable:
let previousRecipents = pullRequests.recipents
let allRecipents = previousRecipents.append(newRecipent) // Assuming preivousRecipents is an array and you have the new Recipent
recievers.child("recipents").setValue(allRecipents)
To use the updateChildValues, it works very similar.
let previousRecipents = pullRequests.recipents
let allRecipents = previousRecipents.append(newRecipent) // Assuming preivousRecipents is an array and you have the new Recipent
let parametersToUpdate = ["recipents": allRecipents]
recievers.updateChildValues(parametersToUpdate)
For further information on how to update, check the following link:
https://firebase.google.com/docs/database/ios/save-data
Hope it helps!