how parsing Firebase FDatasnapshot json data in swift - ios

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)
}

Answer 3

Try to play with this:
func makeItems(from snapshot: DataSnapshot) -> [SimpleItem] {
var items = [SimpleItem]()
if let snapshots = snapshot.children.allObjects as? [DataSnapshot] {
for snap in snapshots {
if let postDictionary = snap.value as? Dictionary<String, AnyObject> {
let item = SimpleItem(parentKey: snap.key, dictionary: postDictionary)
items.append(item)
}
}
}
return items
}
func loadItems() {
firebaseService.databaseReference
.child("items")
.queryOrdered(byChild: "date")
.queryLimited(toLast: 5)
.observeSingleEvent(of: .value) { snapshot in
let items = self.makeItems(from: snapshot)
print("🧀 \(items)")
}
}
class SimpleItem {
var parentKey: String?
var id: String?
var description: String?
init(parentKey: String, dictionary: [String : AnyObject]) {
self.parentKey = parentKey
id = dictionary["id"] as? String
description = dictionary["description"] as? String
}
}

Answer 4

You could parse it maually with Dictionary or you can use my library.
Example code for your case:
func main(){
let root=SnapshotParser().parse(snap: Snapshot, type: Root.self)
}
class Root: ParsableObject {
var title:String?=nil
var images:Images?=nil
required init(){}
func bindProperties(binder: SnapshotParser.Binder) {
binder.bindField(name: "title", field: &title)
binder.bindObject(name: "images", field: &images)
}
}
class Images: ParsableObject {
var main:String?=nil
var others:[Int:String]?=nil
required init(){}
func bindProperties(binder: SnapshotParser.Binder) {
binder.bindField(name: "main", field: &main)
binder.bindDictionary(name: "others", dict: &others)
}
}

Answer 5

This will parse all the snapshot children in the single object and convert it in array and you can easily parse the array of children with index
if let snap = snapshot.children.allObjects as? [DataSnapshot]{
print(snap)
for (index,val) in snap.enumerated(){
print("values")
print(val)
print(val.value)
}
}