I have this chunk of code which returns the results from a Firestore query. Because I want to make sure that the values exists I'm checking every single one of them like if let driverLat = packageDetails["driverLat"] as? Double.. etc and also casting them. It is getting really annoying and I was wondering if there is a better solution to this?
db.collection("packages").document(documentID).getDocument() { (document, error) in
if let document = document, document.exists {
if let packageDetails = document.data() as [String: AnyObject]? {
if let driverLat = packageDetails["driverLat"] as? Double, let driverLon = packageDetails["driverLon"] as? Double {
if let destinationLat = packageDetails["destinationLat"] as? Double, let destinationLon = packageDetails["destinationLon"] as? Double {
// more code
}
}
}
}
}
I would say that you should use multiple guard-let statements. This prevents the pyramid shaped code which decreases the readability.
It would look like so:
typealias Json = [String: AnyObject]
db.collection("packages").document(documentID).getDocument() { (document, error) in
guard let document = document, document.exists else { return }
guard let packageDetails = document.data() as Json? else { return }
guard let driverLat = packageDetails["driverLat"] as? Double else { return }
guard let driverLon = packageDetails["driverLon"] as? Double else { return }
guard let destinationLat = packageDetails["destinationLat"] as? Double else { return }
guard let destinationLon = packageDetails["destinationLon"] as? Double else { return }
// more code
}
Related
I am trying to get data from firestore collection and assign it to an array of dictionaries. for this part of the code below... i get the error "Cast from 'QuerySnapshot?' to unrelated type '[[String : Any]]' always fails" and the console prints "is not working".
guard let snap = snapshot as? [[String:Any]] else {
print("is not working")
completion(.failure(DatabaseError.failedToFetch))
return
}
Here is the full code.
// fetches and returns all conversations for the user with passed in uid
public func getAllConversations(for uid: String, completion: #escaping(Result<[Conversation], Error>) -> Void) {
print("fetching all convos")
//NEW
let db = Firestore.firestore()
let CurrentUser = Auth.auth().currentUser?.uid
let ListRef = db.collection("users").document(CurrentUser!).collection("conversations")
// fetch the current users convo list
ListRef.getDocuments { snapshot, error in
if let err = error {
debugPrint("Error fetching documents: \(err)")
} else {
guard let snap = snapshot as? [[String:Any]] else {
print("is not working")
completion(.failure(DatabaseError.failedToFetch))
return
}
print("is working")
let conversations: [Conversation] = snap.compactMap({ dictionary in
guard let id = dictionary["id"] as? String,
let name = dictionary["name"] as? String,
let otherUserUID = dictionary["other_user-uid"] as? String,
let latestMessage = dictionary["latest-message"] as? [String:Any],
let date = latestMessage["date"] as? String,
let message = latestMessage["message"] as? String,
let isRead = latestMessage["is-read"] as? Bool else {
return nil
}
//save other user ID to a global var
self.test = otherUserUID
//assign data into an array of dictionaries
let latestConvoObject = LatestMessage(date: date, text: message, isRead: isRead)
return Conversation(id: id, name: name, otherUserUid: otherUserUID, latestMessage: latestConvoObject)
})
completion(.success(conversations))
}
}
}
There are a numbers of way to read that data, and the process can be simplified by conforming objects to the codable protocol but let me provide a straight forward example. I don't know what your Conversation object looks like so here's mine
class ConversationClass {
var from = ""
var to = ""
var msg = ""
var timestamp = 0
convenience init(withDoc: DocumentSnapshot) {
self.init()
self.from = withDoc.get("from") as? String ?? "no from"
self.to = withDoc.get("to") as? String ?? "no to"
self.msg = withDoc.get("msg") as? String ?? "no msg"
self.timestamp = withDoc.get("timestamp") as? Int ?? 0
}
}
and then here's the the code that reads in all the conversation documents from a Collection, stores each in a ConversationClass object, puts those in an array and returns it through an escaping completion handler
func getConversations(completion: #escaping( [ConversationClass] ) -> Void) {
let conversationCollection = self.db.collection("conversations")
conversationCollection.getDocuments(completion: { snapshot, error in
if let err = error {
print(err.localizedDescription)
return
}
guard let docs = snapshot?.documents else { return }
var convoArray = [ConversationClass]()
for doc in docs {
let convo = ConversationClass(withDoc: doc)
convoArray.append(convo)
}
completion(convoArray)
})
}
I wonder how to get an Dictionary from my Firestore. For normal Arrays I've done it like that:
func returnArray(){
let newpath = Firestore.firestore().collection(path)
newpath.addSnapshotListener { (querySnapshot, error) in
guard let documents = querySnapshot?.documents else {
return
}
self.Array = documents.map { (queryDocumentSnapshot) -> String in
let data = queryDocumentSnapshot.data()
let Name = data["myField"] as? String ?? ""
return Name
}
}
}
That works perfectly fine. My question is now how I have to change my code that its getting an Array out of the Firebase. I had an idea, but it doesn't work:
func returnDictionary(){
let newpath = Firestore.firestore().collection(path)
newpath.addSnapshotListener { (querySnapshot, error) in
guard let documents = querySnapshot?.documents else {
return
}
self.Dictionary = documents.map { (queryDocumentSnapshot) -> // I don't know what to fill here
in
let data = queryDocumentSnapshot.data()
let Name = data["AnzeigeName"] as? String ?? ""
let ID = data["selfID"] as? String ?? ""
return ID: Name
}
}
}
What can I try next?
.map is going to give you an array, but you can use Dictionary's init(uniqueKeysWithValues:) to turn this into a Dictionary:
let dictionary : Dictionary<String,String> = .init(uniqueKeysWithValues: documents.compactMap { queryDocumentSnapshot -> (String,String)? in
let data = queryDocumentSnapshot.data()
if let name = data["AnzeigeName"] as? String, let id = data["selfID"] as? String {
return (id, name)
}
return nil
})
It's important to know that uniqueKeysWithValues will crash if the keys are not in fact unique, so you'd want to check for that first (look at #New Dev's comment about init(_:uniquingKeysWith:) to handle this). I'm also using compactMap to get rid of nil values.
(Note: In Swift, generally variable names are lowercased and type names are uppercased. Going against that pattern can make your code challenging to read for others)
Firestore Example
{
name: "Anonymous"
pet {
name: "Max"
age: "3"
}
}
Query
Firebase.firestore().collection(path).getDocuments { querySnapshot, error in
if let error = error {
print(error.localizedDescription)
} else {
for document in querySnapshot!.documents {
let data = document.data()
let name = data["name"]
let pet = data["pet"] as! Dictionary<String, String>
print("Name: \(name)")
print("Pet-name: \(pet["name"]!)")
print("Pet-age: \(pet["age"]!)")
}
I'm trying to compare my responses with other people's responses in the firebase database. My script currently has 2 if statements saying if it's my response, record my answers and then use that to compare against other responses, but it doesn't register my second if statement.
let responsesReference = Database.database().reference().child("responses")
responsesReference.observeSingleEvent(of: .value) { (snapshot: DataSnapshot) in
guard let json = snapshot.value as? [String: Any] else { return }
do {
var similarities = [Similarity]()
for answerElement in json {
if self.currentUser.uid == answerElement.key,
let myanswer = answerElement.value as? [String: Any] {
if self.currentUser.uid != answerElement.key, //DOES NOT REGISTER
let otheranswer = answerElement.value as? [String: Any] {
let percentage = myanswer.similarity(with: otheranswer)
similarities.append(
Similarity(name: answerElement.key, percentage: percentage, answer: otheranswer)
)
}
}
}
self.similarities = similarities.sorted(by: { (a, b) -> Bool in
return a.percentage > b.percentage
})
self.tableView.reloadData()
}
Here's your code properly formatted (I copy and pasted it with no changes other than formatting it)
do {
var similarities = [Similarity]()
for answerElement in json {
if self.currentUser.uid == answerElement.key, let myanswer = answerElement.value as? [String: Any] {
if self.currentUser.uid != answerElement.key, let otheranswer = answerElement.value as? [String: Any] {
let percentage = myanswer.similarity(with: otheranswer)
similarities.append( Similarity(name: answerElement.key, percentage: percentage, answer: otheranswer) )
}
}
Take a look here
if self.currentUser.uid == answerElement.key
and note the next if is nested inside that one
if self.currentUser.uid == answerElement.key
if self.currentUser.uid != answerElement.key
If those two vars are equal in the outside if, they will be equal with the inside if as well so the second check will always fail.
The generic solution is to use and else with your if
if self.currentUser.uid == answerElement.key {
let myanswer = answerElement.value as? [String: Any] <- OPTIONAL!
//do something because they are equal
} else {
let otheranswer = answerElement.value as? [String: Any] <- OPTIONAL!
// do something else because they are NOT equal
}
also note that you've got some optionals in that code and if those go to nil your app will either crash or silently fail with no indication as to why.
The logic isn't exactly clear in this code
let percentage = myanswer.similarity(with: otheranswer)
as each time through the loop
for answerElement in json {
}
there will only be one answer in an answerElement. e.g. there won't be a myAnswer and otherAnswer, there will only be theAnswer. Perhaps there should be a comparison to the prior answer from the loop; I'll expand on that
Here's an example based on reading in all users, getting the answer for this user, removing the user from the results and then comparing that to other users answers. Assume users uid's are used at the key to each user node (which also contains an answer they provides) and we know the auth'd users uid.
let thisUsersUid = "uid_1"
let usersRef = self.ref.child("users") //self.ref points to MY firebase
usersRef.observeSingleEvent(of: .value, with: { snapshot in
var allUsersSnap = snapshot.children.allObjects as! [DataSnapshot]
guard let index = allUsersSnap.firstIndex { $0.key == thisUsersUid } else {
print("no user: \(thisUsersUid) found")
return
}
let thisUserSnap = allUsersSnap[index] //keep this so it can be compared later
allUsersSnap.remove(at: index)
let thisUsersAnswer = thisUserSnap.childSnapshot("answer").value as? String ?? "No Answer"
for otherUserSnap in allUsersSnap {
let otherUsersAnswer = otherUserSnap.childSnapshot("answer").value as? String ?? "No Answer"
if orherUsersAnswer == thisUsersAnswer {
//do something because the answers match
}
}
})
Here is the database
I'm trying to append isDisable to an array
What i've come so far:
func retrieving(){
Database.database().reference().child("ServingHours/\(choosenDate)").observeSingleEvent(of: .value, with: {(snapshot) in
if let eachDict = snapshot.value as? NSDictionary{
for each in eachDict{
print(each.value)
}
}
}, withCancel: {(Err) in
})
}
with the result in console:
{
isDisable = false;
numberOfRegistration = 0;
}
{
isDisable = false;
numberOfRegistration = 0;
}
{
isDisable = false;
numberOfRegistration = 0;
}
{
isDisable = false;
numberOfRegistration = 0;
}
From this, I don't know what to do to get a specific value from each.value
You're retrieving your specific dates objects which have 2 items within them (isDisable and numberOfRegistration). When you retrieve them from Firebase, you're type casting them into NSDictionary using "as?".
Your values seem to be in String format, therefore, you can retrieve them from the NSDictionary using:
let isDisabled = eachDict["isDisable"] as? String
let numberOfRegistration = eachDict["numberOfRegistration"] as? String
You can also directly set your values in Firebase to be a Bool or Int and you can typecast your retrieved objects into Bool (isDisable) and Int (numberOfRegistration). But it looks like they are currently Strings, so your code would like this:
func retrieving(){
Database.database().reference().child("ServingHours/\(choosenDate)").observeSingleEvent(of: .value, with: {(snapshot) in
if let eachDict = snapshot.value as? NSDictionary{
let isDisabled = eachDict["isDisable"] as? String
let numberOfRegistration = eachDict["numberOfRegistration"] as? String
print(isDisabled)
print(numberOfRegistration)
}
}, withCancel: {(Err) in
})
}
Also, if you want to retrieve a value directly, then you don't need to use an NSDictionary. You can just directly cast that value you retrieve into whatever type of object you have. For example, say you want to retrieve your "isDisable" value directly:
func retrieving(){
Database.database().reference().child("ServingHours/\(choosenDate)").child("isDisable").observeSingleEvent(of: .value, with: {(snapshot) in
if let isDisable = snapshot.value as? String{
print(isDisable) }
Check out the Firebase official documentation for Swift:
https://firebase.google.com/docs/database/ios/read-and-write
You need to cast to a dictionary once again (and don't use NSDictionary)
if let eachDict = snapshot.value as? [String: AnyObject]{
for each in eachDict {
if let innerDict = each as? [String: AnyObject] {
//innerDict now contains isDisable and numberOfRegistration
if let isDisable = innerDict["isDisable"] as? String
print(isDisable)
}
if let numberOfRegistration = innerDict["numberOfRegistration"] as? String {
print(numberOfRegistration)
}
}
}
}
I am trying to parse the emergency data in into emergency struct but it never statifies the condition and get into else case.Here is my code and structure.Some thing i have written woring in first line.
if let emergencyDict = snapshotValue["emergency"] as? [String:[String:Any]]{
for (emerId, emerData) in emergencyDict {
let emer = Emergency.init(emergency: emerData as NSDictionary)
emergency.append(emer)
}
}
else{
let emer = Emergency.init(emerg: "" as AnyObject)
emergency.append(emer)
}
struct Emergency{
var emer_id: String
var emer_name: String
var emer_phoneNo: String
init(emergency: NSDictionary) {
if emergency.object(forKey: "id") != nil {
emer_id = emergency.object(forKey: "id") as! String
}
else{
emer_id = ""
}
}
}
The problem you are having emergency as Array with type [Any] and if you remove the first object then you get Array of type [[String:Any]]. So try like this way.
if let array = snapshotValue["emergency"] as? [Any],
let emergencyArrar = Array(array.dropFirst()) as? [[String:Any]] {
print(emergencyArray)
for emergency in emergencyArray {
print(emergency)
}
}
You have written wrong in this line:
if let emergencyDict = snapshotValue["emergency"] as? [String:[String:Any]]{
It should be:
if let emergencyDict = snapshotValue["emergency"] as? [[String:Any]]{
This question should belong to query from firebase database.
// you have to get the children in emergency,
// then get the value(dictionary) of each child
ref.child("emergency").observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
let keys = value?.allKeys // [1, 2, 3 ....]
for key in keys {
ref.child("emergency").child(key)..observeSingleEvent(of: .value, with: { (snapshot) in
let value = snapshot.value as? NSDictionary
// Here is your dictionary
}
}
}) { (error) in
print(error.localizedDescription)
}