How to retrieve child snapshots in Firebase? - swift

Im trying to create a childSnapshot in firebase using for child in snapShot.children I know back then I used to be able to make it work, Im not sure if this was change in the new update
-old way that used to work
for child in snapshot.children {
let firUserId = child.childSnapshot(forPath: "userId").value! as! String
let receivePostSnapshot = child.childSnapshot(forPath: "receivePost")
}
my current code does not work
func displayAvailaibleHelprOnMap(){
let refUrl = "frontEnd/users"
let childRef = Ref.childRef(refUrl: refUrl)//.child("users")
childRef.observe(.value, with: {snapshot in
let dict = snapshot.value as? NSDictionary
for child in snapshot.children{
// I want to use child snapshot here
//let childDict = child.childSnapshot(forPath: "receivePost")
}
}

Try:
var ref: FIRDatabaseReference!
ref = FIRDatabase.database().reference()
ref.child("users").observeSingleEvent(of: .value, with: { (snapshot) in
if let snapshots = snapshot.children.allObjects as? [FIRDataSnapshot] {
for snap in snapshots
{
let firUserId = child.childSnapshot(forPath: "userId").value! as! String
let receivePostSnapshot = child.childSnapshot(forPath: "receivePost")
}
}
})

try this
let mRef = mRestCallObj.getReferenceFirebase()
mRef!.child("users").queryOrderedByChild("receivePost").observeEventType(.ChildAdded, withBlock: { snapshot in
let userName = snapshot.value!["receivePost"] as? String
}

Try this-
let ref = FIRDatabase.database().reference().child("Users + infomation").child(userid).child("cats")`
ref.observeSingleEventOfType(.Value, withBlock : {(snapShot) in
if let val = snapShot.value as? Int {print(snapShot)}

Related

Cant fetch from Firebase Realtime Database

I don't know why cant find how get friends Ids.
her is my code:
func fetchUsers() {
let ref = Firebase.Database.database().reference()
guard let userId = Auth.auth().currentUser?.uid else { return }
let userID = userId
ref.child("Users").child(userID).observe(.childAdded) { (snapshot) in
print("snapshot...\(snapshot)")
let user = User()
if let dictionary = snapshot.value as? [String:AnyObject]{
user.currentUserFriends = dictionary["Friends"] as? String
print("dictionary...\(user.currentUserFriends ?? "no value")")
}
}
}
and my tree from firebase is Users-Uid-Friends-friendID-true.
Solved!
ref.child("Users").child(userID!).child("Friends").observeSingleEvent(of: .value) { (snapshot) in
print("snapshot...\(snapshot)")
let dic = snapshot.value as! NSDictionary
for (key,value) in dic{
let friendsID = key
let friendBool = value
print("key is \(friendsID) and value is \(friendBool)")
let user = User()
user.currentUserFriends = key as? String
}
}

Not able to read data from Firebase realtime database

I have stored the comments under a post in firebase realtime database. The problem i have is that when i try to parse out the data from firebase i get an error that says Unexpectedly found nil while unwrapping an Optional value. So for example if i try to pront the data stored under degree, i get this nil error. But when i print "comments" instead of the "degree" i successfully fetch the data. My database structure looks like this.
func obeserveComments() {
// get auto-id of post
let commentKey = self.keyFound
let postRef = Database.database().reference().child("posts").child(commentKey)
var tempComments = [Comments]()
postRef.observe(.value, with: {(snapshot) in
if let dict = snapshot.value as? [String:Any] {
if let comments = dict["comments"] as? [String:Any] {
let degree = comments["reply degree"] as! String
// let name = comments["reply name"] as! String
// let text = comments["reply text"] as! String
// let university = comments["reply university"] as! String
// let photoURL = comments["reply url"] as! String
// let url = URL(string: photoURL)
// let timestamp = comments["timestamp"] as! Double
print(degree)
}
}
})
}
The answer by #aytroncb is a good answer, I prefer to leave Firebase data 'Firebasy' as long as possible. In other words coverting to dictionaries looses ordering and and find code like this
[String: [String: [String: Any]]]
To be very hard to read.
I prefer
let snap = snapshot.childSnapshot("comments") //snap becomes a DataSnapshot
So my solution maintains the order and leverages .childSnapshot to leave data in it's DataSnapshot form.
func readPostComments() {
let postRef = self.ref.child("posts") //self.ref points to my firebase
postRef.observeSingleEvent(of: .value, with: { snapshot in
let allPosts = snapshot.children.allObjects as! [DataSnapshot]
for postSnap in allPosts {
print("postId: \(postSnap.key)")
let commentsSnap = postSnap.childSnapshot(forPath: "comments") //will be a DataSnapshot
let allComments = commentsSnap.children.allObjects as! [DataSnapshot]
for commentSnap in allComments {
print(" commentId: \(commentSnap.key)")
let replyDegree = commentSnap.childSnapshot(forPath: "reply_degree").value as? String ?? "No Degree"
let replyName = commentSnap.childSnapshot(forPath: "reply_name").value as? String ?? "No Name"
print(" degree: \(replyDegree) by: \(replyName)")
}
}
})
}
EDIT
For a single post, remove the top part of the code that reads in and iterates over all posts.
func readCommentsForOnePost() {
let postRef = self.ref.child("posts")
let postCommentRef = postRef.child("post_0")
postCommentRef.observeSingleEvent(of: .value, with: { snapshot in
print("postId: \(snapshot.key)")
let commentsSnap = snapshot.childSnapshot(forPath: "comments") //will be a DataSnapshot
let allComments = commentsSnap.children.allObjects as! [DataSnapshot]
for commentSnap in allComments {
print(" commentId: \(commentSnap.key)")
let replyDegree = commentSnap.childSnapshot(forPath: "reply_degree").value as? String ?? "No Degree"
let replyName = commentSnap.childSnapshot(forPath: "reply_name").value as? String ?? "No Name"
print(" degree: \(replyDegree) by: \(replyName)")
}
})
}
Its because firebase is returning your data like this
{
"MAKFW244kdL)Cw;1": [Array of data],
"LOPSw!35pa3flAL4": [Array of data],
"ALV34VR4_A6Vn1a": [Array of data]
}
So change your initial casting of snapshot.value to this:
if let dict = snapshot.value as? [String: [String: Any]]
then loop through that new dictionary like this:
for objectJson in dict.values {
if let comments = objectJson["comments"] as? [String: [String: Any]] {
for commentJson in comments.values {
let degree = commentJson["reply_degree"] as? String
}
}
}
Update
Just read through your post again and noticed your trying to access the comments directly with a key, your first going to need to provide the PostId. Then you can use the above code to loop through the objects
let postRef = Database.database().reference().child("posts").child(postID)
alternatively I believe you can have the comments returned as a normal list by doing something like this:
let postRef = Database.database().reference().child("posts").child("\(postID)/{id}")

Firebase getting data in letter order

How do I sort the following data in letter order? So "deviceRooms1, deviceRooms2, deviceRooms3, ..." I want the data sorted.
#objc func fetchRooms()
{
let ref = Database.database().reference().child("0").child("Rooms")
ref.observeSingleEvent(of: .value, with: { (snapshot) in
//let value: NSDictionary = snapshot.value as! NSDictionary
let dic = snapshot.value as! [String:String]
self.tableRowss = Array(dic.values)
self.myTableView.reloadData()
})
}
You can try
let dic = snapshot.value as! [String:String]
let sortedKeys = Array(dic.keys).sorted(by:<)
self.tableRowss = sortedKeys.map { dic[$0]! }
self.myTableView.reloadData()

Can't get node of firebase children

Hi there i'm newest in swift. I am working with a firebase database with at 2 layer of hierarchy as well as many children for each node. I got 1st layer (descript, enddata and other), but i stll can't get the news node. Is in 3 to 5 random keys. I sow many issues but still not have issue for me.
I'm understand i'm doing some wrong but what?
The Firebase is:
i need retreat the news child
struct is
struct ICONews {
let ICOId: String
let news1: String
let news2: String
let news3: String
init?(ICOId: String, dict: [String: Any] ) {
self.ICOId=ICOId
guard let news1 = dict[""] as? String,
let news2 = dict[""] as? String,
let news3 = dict[""] as? String
else { return nil }
self.news1 = news1
self.news2 = news2
self.news3 = news3
}
}
struct NewsSnapShot {
let posts: [ICONews]
init?(with snapshot: DataSnapshot) {
var posts = [ICONews] ()
guard let snapDict = snapshot.value as? [String: [String: Any]] else { return nil }
for snap in snapDict {
guard let post = ICONews (ICOId: snap.key, dict: snap.value) else {continue}
posts.append(post)
}
self.posts=posts
}
}
class of DataBase
class DatabaseService {
static let shared = DatabaseService()
private init(){}
let ICOReference = Database.database().reference()
}
and retreat method
DatabaseService.shared.ICOReference.child("news").observe(DataEventType.value, with: { (snapshot) in
guard let postsSnapShot = ICOSnapShot(with: snapshot) else {return}
})
done
Database.database().reference().observeSingleEvent(of: .value, with: {(snapshot) in
let enumerator = snapshot.children
while let rest = enumerator.nextObject() as? DataSnapshot {
let values = (rest as! DataSnapshot).value as? NSDictionary
let enumeratorMap1 = (rest as! DataSnapshot).children
while let rest2 = enumeratorMap1.nextObject() as? DataSnapshot {
let valuesMap1 = (rest2 as! DataSnapshot).value as? NSDictionary
if (rest2 as! DataSnapshot).key == "news" {
print(rest2.value)
}
}
}
})
Make the the Firebase Api call like
Database.database().reference().child("users").child(userID).observe(.childAdded, with: { (snapshot) in
if snapshot.exists() {
let receivedMessage = snapshot.value as! [String: Any]
let name = receivedMessage["name"] as? String ?? ""
let id = receivedMessage["id"] as? Double ?? 0.0
let profileurl = receivedMessage["url"] as? String ?? ""
completion(User(name: name, id: id, url: url))
} else {
failure()
}
})

How to read data from firebase

This is my realtime database structure. I have only 1 item in club. In reality, I have many items.
I want to read all clubs information, and try to get the related address using club's key.
here is my code:
func loadClubs() {
ref = Database.database().reference()
let clubRef = ref.child("club")
let refHandle = clubRef.observe(DataEventType.value, with: { (snapshot) in
if let c = snapshot.value as? [String : AnyObject] {
let name = c["name"] as! String // PRINT NIL
}
// ...
})
}
How can I retrieve a club's name, courtNum, explanation,...?
try this:-
ref = Database.database().reference()
ref.child("club").observe(.value, with: { (snapshot) in
print("clubs: \(snapshot)")
if(snapshot.exists()) {
let array:NSArray = snapshot.children.allObjects as NSArray
for obj in array {
let snapshot:FIRDataSnapshot = obj as! FIRDataSnapshot
if let childSnapshot = snapshot.value as? [String : AnyObject]
{
if let clubName = childSnapshot["name"] as? String {
print(clubName)
}
}
}
}
}