My Firebase datastructure looks like this:
user is the parent, underneath it is the user uid and Dream, Grocery list is the note titles and they have their content. I am trying to observe the value of the titles and put them into an array to put in a tableview. This is what I have so far but since the titles of the note are different every time, I dont know how to do a model for that:
DataService.ds.REF_CURRENT_USER.observe(.value) { (snapshot) in
for snap in snapshot.children.allObjects as! [DataSnapshot] {
print("Note Title:\(snap.key)")
}
}
This prints out everything including email and provider but I dont want that I just want it to print Dream and Grocery List
Use the below code to get your required values
guard let uid = Auth.auth().currentUser?.uid else {
return
}
let ref = Database.database().reference().child("users").child("\(uid)")
ref.child("Dream").observe(.value, with: { (snapshot) in
guard let dictionary = snapshot.value as? [String : AnyObject] else {
return
}
print(dictionary["content"] as? String)
}, withCancel: nil)
ref.child("Grocerylist").observe(.value, with: { (snapshot) in
guard let dictionary = snapshot.value as? [String : AnyObject] else {
return
}
print(dictionary["content"] as? String)
}, withCancel: nil)
Related
I am wanting to capture all the values in my childByAutoId in firebase. Essentially, it stores all the items that a person has shortlisted. However, I do not seem to be capturing this, and I assume it is because I am not calling the snapshot correctly to factor the auto id's.
Database:
userID
-> Favourited
-> Auto Id
-> itemName: x
-> Auto Id
-> itemName: x
-> Auto Id
-> itemName: x
Code:
func retrieveItems() {
guard let userId = Auth.auth().currentUser?.uid else { return }
let ref = Database.database().reference().child("users/\(userId)/Favourited")
ref.observe(.value, with: { (snapshot) in
if snapshot.childrenCount>0 {
self.favUsers.removeAll()
for likes in snapshot.children.allObjects as! [DataSnapshot] {
let likesObject = likes.value as? [String: AnyObject]
let itemName = likesObject!["itemName"]
let likesList = Names(id: likes.key, itemName: itemName as! String?)
self.favUsers.append(likesList)
}
} else {
print("not yet")
}
})
self.favList.reloadData()
}
Could someone have a look and let me know what I may be doing wrong? Thank you!
This happens because Firebase loads data asynchronously, and right now you're calling reloadData before the self.favUsers.append(likesList) has ever run.
The call to reloadData needs to be inside the close/completion handler that is called when the data comes back from Firebase:
ref.observe(.value, with: { (snapshot) in
if snapshot.childrenCount>0 {
self.favUsers.removeAll()
for likes in snapshot.children.allObjects as! [DataSnapshot] {
let likesObject = likes.value as? [String: AnyObject]
let itemName = likesObject!["itemName"]
let likesList = Names(id: likes.key, itemName: itemName as! String?)
self.favUsers.append(likesList)
}
self.favList.reloadData() // 👈 Move this here
} else {
print("not yet")
}
})
I also recommend checking out some of these answers asynchronous data loading in Firebase.
My Firebase Database
More specifically, I have randomly generated children(Listings) and from those randomly generated Listings I would like to get the string value from the keys.
For example, if I wanted the Photo URL address, I would like to get the string value of the key "PhotoURL:".
Thank you in advance !
First you need to do is to import Firebase and then call a function from the Database class like so:
let ref = Database.database().reference().child("Listings")
You can call child recursively to go deeper into your tree
//.child("Listings").child("SomeListing").child("PhotoURL")
Then call observeSingleEvent to receive the values from firebase.
Your value is stored in the snapshot variable
ref.observeSingleEvent(of: .value, with: { (snapshot) in
guard let listingsDictionary = snapshot.value as? [String: Any] else { return }
listngsDictionary.forEach({ (key, value) in
// Here you can iterate through it
})
}) { (err) in
print("Failed to fetch following listings:", err)
}
Here is the code to get child values from Listings.Â
var ListArr = [ListModel]()
let ref = Database.database().reference().child("Listings")
ref.observe(.childAdded, with: { (snapshot) in
print(snapshot)
guard let dictionary = snapshot.value as? [String : AnyObject] else {
return
}
let Obj = ListModel()
Obj.UID = snapshot.key
Obj.PhotoURL = dictionary["PhotoURL"] as? String
self.ListArr.append(Obj)
}, withCancel: nil)
}
You can set up the model class
class ListModel: NSObject {
var UID:String?
var PhotoURL:String?
}
firebase structure
In the firebase structure you can see i have to delete specific user (currentUserId) in all the groups:
it's what i try to do:
###########################UPDATED###################################
let groupsRef = self.root.child("groups")
groupsRef.observeSingleEvent(of: .value, with: { snapshot in
for groupChild in snapshot.children {
let groupSnap = groupChild as! DataSnapshot
var dict = groupSnap.value as! [String: Any]
let uid = dict["utenti"] as! [String: Bool]
for each in uid {
if each.key == self.currentUserID{
print(each.key)
//i now need a way to remove this key:value
}
}
}
})
I'm new so i'm not able to go further in extracting every key of ditcionary, than i will compare to the one i have to delete and if it's the same i will delete.
Can someone help?
let groupsRef = self.root.child("groups")
groupsRef.observeSingleEvent(of: .value, with: { snapshot in
for groupChild in snapshot.children {
let groupSnap = groupChild as! DataSnapshot
let groupKey = groupSnap.key
//added a groupKey to track the id of each group
var dict = groupSnap.value as! [String: Any]
var uid = dict["utenti"] as! [String: Bool]
//then for each key:value in uid check if is there a key = to currentuserID
for each in uid {
if each.key == self.currentUserID{
uid.removeValue(forKey: each.key)
//here you remove currentuserId from the dictionary and below
//finally you set back the new value of the dictionary without currentuserId
self.root.child("groups").child(groupKey).child("utenti").setValue(uid)
}
}
}
})
you can use
for (key, value) in uid {
}
to loop over a dictionary.
But really, looking in the official documentation of swift would give you the right answer...
let groupsRef = self.root.child("groups")
groupsRef.observeSingleEvent(of: .value, with: { snapshot in
for groupChild in snapshot.children {
let groupSnap = groupChild as! DataSnapshot
for subGroupChild in groupSnap.children {
//Here you need to remove that specific user if condition match
//specificUserUID is that user's id that user to be deleted
if let snapref = subGroupSnap as! DatabaseReference {
snapref.queryOrdered(byChild: "utenti").queryEqual(toValue: specificUserUID).observe(.childAdded, with: { (snapshot) in
snapshot.removeValue(completionBlock: { (error, reference) in
if error != nil {
print("There has been an error:\(error)")
}
})
})
}
}
}
})
Your code will go like above you just need find thaat user by user ID and delete that particular snapshot.
I have two observers, the second observer is dependent on the first observers value. I can't seem to get the first observer to work, I am not getting any errors on Xcode. The first function has to check the Users profile for information and then use that information to search for different information in the database. Here is my code:
func loadposts() {
ref = Database.database().reference()
let trace = Performance.startTrace(name: "test trace")
trace?.incrementCounter(named:"retry")
let userID = Auth.auth().currentUser?.uid
print(userID!)
ref.child("Users").child(userID!).observeSingleEvent(of: .value, with: { (snapshot) in
// Get user value
let value = snapshot.value as? NSDictionary
let one1 = value?["Coupon Book"] as? String ?? ""
print("one1: \(one1)")
self.bogus.set(one1, forKey: "bogus")
}) { (error) in
print(error.localizedDescription)
}
delay(0.1) {
print("bogus: \(self.bogus.string(forKey: "bogus"))")
Database.database().reference().child("Coupons").child(self.bogus.string(forKey: "bogus")!).observe(.childAdded) { (Snapshot : DataSnapshot) in
if let dict = Snapshot.value as? [String: Any] {
let captiontext = dict["company name"] as! String
let offerx = dict["offer count"] as! String
let logocomp = dict["logo"] as! String
let actchild = dict["childx"] as! String
let post = Post(captiontext: captiontext, PhotUrlString: actchild, offertext: offerx, actualphoto: logocomp)
self.posts.append(post)
self.tableview.reloadData()
print(self.posts)
}
}
}
trace?.stop()
}
Any help is appreciated.
self.bogus.string(forKey: "bogus"))" is nil because observeSingleEvent is an async method, so to get the required results you need to call the second observer inside the first observer or you can use the completion handler
You can use the completionHandler like this:
guard let uid = Auth.auth().currentUser?.uid else {
return
}
func firstObserverMethod(completionCallback: #escaping () -> Void) {
ref.child("Users").child(uid).observeSingleEvent(of: .value, with: { (snapshot) in
// Get user value
if let value = snapshot.value as? [String: Any] {
let one1 = value["Coupon Book"] as? String
print("one1: \(one1)")
self.bogus.set(one1, forKey: "bogus")
completionCallback()
}
}) { (error) in
print(error.localizedDescription)
}
}
Now using the above method:
firstObserverMethod {
print("bogus: \(self.bogus.string(forKey: "bogus"))")
guard let bogusString = self.bogus.string(forKey: "bogus") else {
print("bogus is not set properly")
return
}
Database.database().reference().child("Coupons").child(bogusString).observe(.childAdded) { (Snapshot : DataSnapshot) in
if let dict = Snapshot.value as? [String: Any] {
let captiontext = dict["company name"] ?? ""
let offerx = dict["offer count"] ?? ""
let logocomp = dict["logo"] ?? ""
let actchild = dict["childx"] ?? ""
let post = Post(captiontext: captiontext, PhotUrlString: actchild, offertext: offerx, actualphoto: logocomp)
self.posts.append(post)
DispatchQueue.main.async {
self.tableview.reloadData()
}
print(self.posts)
}
}
}
Note: You should use optional binding to get the values from optional
Since you are using the result of the 1st observer in the reference of your 2nd observer, it's a very bad idea to add the 2nd observer right below the first observer. And adding a delay won't be a viable solution : these two calls are asynchronous, which means that the reason why you are not getting might very likely be because the 2nd observer is triggered even before the 1st has returned any data.
The solution here, would be using a completion handler, or you could just incorporate your 2nd observer inside the completion block of the 1st, to be make sure that the proper order (1st observer -> 2nd observer) will always be respected.
It would look somehow like this:
func loadposts() {
// ...
// 1st Observer here
ref.child("Users").child(userID!).observeSingleEvent(of: .value, with: { (snapshot) in
// Get your value here
guard let one1 = snapshot.childSnapshot(forPath: "Coupon Book").value as? String else { return }
// 2nd Observer here. Now you can use one1 safely:
Database.database().reference().child("Coupons").child(one1).observe(.childAdded) { (Snapshot : DataSnapshot) in
// ...
}
})
}
Now, a couple of things that you could also improve in your code, while not directly related to the question:
I would suggest you to make use of guard statements instead force-unwrapping, which may end up in crashing your app at some point.
For example, you could check whether your current user exist or not like so:
guard let currentUserID = Auth.auth().currentUser?.uid else {
return
}
// Now you can use safely currentUserID
Also, when you try to get the data out of the snapshot, it's not a good idea either, to use force-casting. You would better write it in this way:
yourRef.observeSingleEvent(of: .value, with: { (snapshot) in
for child in snapshot.children.allObjects as! [DataSnapshot] {
guard let text = child.childSnapshot(forPath: "text").value as? String, let somethingElse = child.childSnapshot(forPath: "otherValue").value as? NSNumber else {
return
}
// And so on, depending of course on what you have in your database.
}
I am using the subscript in the following code incorrectly for this Firebase data pull, but I can't figure out what I am doing wrong. I get an error of Ambiguous use of subscript for the let uniqueID = each.value["Unique ID Event Number"] as! Int line.
// Log user in
if let user = FIRAuth.auth()?.currentUser {
let uid = user.uid
// values for vars sevenDaysAgo and oneDayAgo set here
...
let historyRef = self.ref.child("historyForFeedbackLoop/\(uid)")
historyRef.queryOrdered(byChild: "Unix Date").queryStarting(atValue: sevenDaysAgo).queryEnding(atValue: oneDayAgo).observeSingleEvent(of: .value, with: { snapshot in
if (snapshot.value is NSNull) {
print("user data not found")
}
else {
if let snapDict = snapshot.value as? [String:AnyObject] {
for each in snapDict {
// Save the IDs to array.
let uniqueID = each.value["Unique ID Event Number"] as! Int
self.arrayOfUserSearchHistoryIDs.append(uniqueID)
}
}
else{
print("SnapDict is null")
}
}
})
}
I tried to applying what I learned from this post, but I couldn't figure out what I am missing because I thought I was letting the compiler know what type of dictionary it is with the "as? [String:AnyObject]"
Any thoughts or ideas would be greatly appreciated!
My preferred way of dealing with data is to unwrap the FIRDataSnapshot as late as possible.
ref!.observe(.value, with: { (snapshot) in
for child in snapshot.children {
let msg = child as! FIRDataSnapshot
print("\(msg.key): \(msg.value!)")
let val = msg.value! as! [String:Any]
print("\(val["name"]!): \(val["message"]!)")
}
})
Taking Frank's feedback into account, here is the actual working code I used that follows that approach in case it's helpful.
// Log user in
if let user = FIRAuth.auth()?.currentUser {
let uid = user.uid
// values for vars sevenDaysAgo and oneDayAgo set here
...
let historyRef = self.ref.child("historyForFeedbackLoop/\(uid)")
historyRef.queryOrdered(byChild: "Unix Date").queryStarting(atValue: sevenDaysAgo).queryEnding(atValue: oneDayAgo).observeSingleEvent(of: .value, with: { snapshot in
if (snapshot.value is NSNull) {
print("user data not found")
}
else {
for child in snapshot.children {
let data = child as! FIRDataSnapshot
let value = data.value! as! [String:Any]
self.arrayOfUserSearchHistoryIDs.append(value["Unique ID Event Number"] as! Int)
}
}
})
}