how parsing Firebase FDatasnapshot json data in swift

Question

I'm having issue getting data from Firebase.

schema is

{
    title: "dog",
    images: {
        main: "dog.png",
        others: {
            0: "1.png",
            1: "2.png",
            2: "3.png"
        }
    }
}

how can i parse FDataSnapshot to swift model??

Answer 1

Firebase is a NoSQL JSON database and has no schema and no tables. Data is stored with a 'tree' structure with nodes; parents and children.

You don't need to parse Firebase JSON data to access it, you can access it directly.

FDataSnapshots contain a .key, which is it's parent key in Firebase and .value. .Value may contain one node, or multiple nodes. The Value will have key:value pairs representing the data within the snapshot

So for your example you will have a Firebase structure like this

dogs
  dog_id_0
    title: "dog"
    type: "Alaskan Malamute"
    images:
        main: "dog.png"
        others:
            0: "1.png"
            1: "2.png"
  dog_id_1
    title: "another dog"
    type: "Boxer"
    images:
        main: "another_dog.png"
        others:
            0: "3.png"
            1: "4.png"

So, say you want to read in each dog_id_x node one at a time and print some values.

var ref = Firebase(url:"https://your-app.firebaseio.com/dogs")

ref.observeEventType(.ChildAdded, withBlock: { snapshot in
    println(snapshot.value.objectForKey("title"))
    println(snapshot.value.objectForKey("type"))
})

This will output

dog
Alaskan Malamute
another dog
Boxer

The dog_id_0 and dog_id_1 are node names created with the Firebase childByAutoId.

You could just as easily create a Dog class, and pass it the FDataSnapshot which will populate the class from the data within the snapshot.

Answer 2

February 2017 Update, Swift 3 Xcode 8

Since a lot of things with Swift3 and Firebase have changed by the time this question was asked I will provide an updated way to parse Firebase data:

    let userID = FIRAuth.auth()?.currentUser?.uid

    //I am registering to listen to a specific answer to appear
    self.ref.child("queryResponse").child(userID!).observeSingleEvent(of: .value, with: { (snapshot) in
        //in my case the answer is of type array so I can cast it like this, should also work with NSDictionary or NSNumber
        if let snapshotValue = snapshot.value as? NSArray{
            //then I iterate over the values
            for snapDict in snapshotValue{
                //and I cast the objects to swift Dictionaries
                let dict = snapDict as! Dictionary<String, Any>
            }
        }
    }) { (error) in
        print(error.localizedDescription)
    }