I have a value I need to read from Firebase and then write it together with multiple other values to Firebase in a transaction of two objects total.
I am creating a CHAT and so when a message is sent, I am creating a chat room for both contacts, each to his own. My code :
private func CreateChatRoom(creatorID: String, creatorName: String ,contactID: String, contactName: String)
{
var creatorImageString: String = ""
var contactImageString: String = ""
ReadContactImage(contactID: contactID)
{
success in
if success
{
contactImageString = self.tempContactImg
}
}
ReadContactImage(contactID: creatorID)
{
success in
if success
{
creatorImageString = self.tempContactImg
}
}
let infoForCreator = [Constants.Chat.ChatRoomsLite.CONTACT_NAME: contactName,
Constants.Chat.ChatRoomsLite.CONTACT_ID: contactID,
Constants.Chat.ChatRoomsLite.NUM_OF_UNREAD_MSGS : 0,
Constants.Chat.ChatRoomsLite.CONTACT_IMG_URL: contactImageString] as [String : Any]
let infoForContact = [Constants.Chat.ChatRoomsLite.CONTACT_NAME: creatorName,
Constants.Chat.ChatRoomsLite.CONTACT_ID: creatorID,
Constants.Chat.ChatRoomsLite.NUM_OF_UNREAD_MSGS : 0,
Constants.Chat.ChatRoomsLite.CONTACT_IMG_URL: creatorImageString] as [String : Any]
let childUpdates = ["\(creatorID)/\(contactID)/": infoForCreator,
"\(contactID)/\(creatorID)/": infoForContact
]
Constants.refs.databaseChatsLite.updateChildValues(childUpdates)
}
private func ReadContactImage(contactID: String, completion: #escaping (Bool) -> ())
{
Constants.refs.databaseUsers.child(contactID).child(Constants.Account.AccountFields.USER_IMAGE_STR).observeSingleEvent(of: .value, with: {(snapshot) in
self.tempContactImg = (snapshot.value as? String)!
completion(true)
})
}
var tempContactImg : String = "";
I read here on SO that the function "ReadContactImage" should run synchronously, but it does not. So I'm left with empty contact images.
I thought about just reading both images in the same function, but CreateChatRoom also needs to be synchronous, so I am left with the same problem, basically.
Does anyone know how to handle this properly ?
Is there maybe an easier way of doing this?
Edit:
If writing to Database is async, I get an exception here:
func AddChatToCollections(chatAsDictionary: NSDictionary!)
{
if chatAsDictionary == nil
{
return
}
let contactName = chatAsDictionary[Constants.Chat.ChatRoomsLite.CONTACT_NAME] as! String
let contactImg = chatAsDictionary[Constants.Chat.ChatRoomsLite.CONTACT_IMG_URL] as! String
//let lastMsg = chatAsDictionary["lastMessage"] as! String
let newMsgs = chatAsDictionary[Constants.Chat.ChatRoomsLite.NUM_OF_UNREAD_MSGS] as! Int
let contactID = chatAsDictionary[Constants.Chat.ChatRoomsLite.CONTACT_ID] as! String
let chatToAdd = PrivateChatLiteObject(chattingWith: contactName, ContactID: contactID, unreadMessages: newMsgs, LastMSG: "", ContactImageStr: contactImg)
chatsDictionary[contactID] = chatToAdd
chatsIndex.append(contactID)
}
When trying to use the information in dictionary, which is taken from Firebase.
That function is called from here:
private func populateActiveChats()
{
let loggedOnUserID = Auth.auth().currentUser?.uid
let ref = Constants.refs.databaseChatsLite.child(loggedOnUserID!)
// Retrieve the products and listen for changes
ref.observe(.value, with:
{ (snapshot) in
for child in snapshot.children.allObjects as! [DataSnapshot]
{
if (self.chatsDictionary.keys.contains(child.key) == false)
{
let chatValueDictionary = child.value as? NSDictionary
self.AddChatToCollections(chatAsDictionary: chatValueDictionary)
self.DispatchQueueFunc()
}
}
})
}
Which is called from viewDidLoad() when I open my Chats page.
Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value
Because chatAsDictionary[CONTACT_NAME] doesn't exist, because when chatAsDictionary gets its data from Firebase, it is not yet written there from the async function
Both methods you call load data from Firebase asynchronously. You can't constructor infoForCreator (et al) until both calls to ReadContactImage have completed.
A simple way to do that is to nest the calls:
var creatorImageString: String = ""
var contactImageString: String = ""
ReadContactImage(contactID: contactID)
{
success in
if success
{
contactImageString = self.tempContactImg
ReadContactImage(contactID: creatorID)
{
success in
if success
{
creatorImageString = self.tempContactImg
let infoForCreator = [Constants.Chat.ChatRoomsLite.CONTACT_NAME: contactName,
Constants.Chat.ChatRoomsLite.CONTACT_ID: contactID,
Constants.Chat.ChatRoomsLite.NUM_OF_UNREAD_MSGS : 0,
Constants.Chat.ChatRoomsLite.CONTACT_IMG_URL: contactImageString] as [String : Any]
let infoForContact = [Constants.Chat.ChatRoomsLite.CONTACT_NAME: creatorName,
Constants.Chat.ChatRoomsLite.CONTACT_ID: creatorID,
Constants.Chat.ChatRoomsLite.NUM_OF_UNREAD_MSGS : 0,
Constants.Chat.ChatRoomsLite.CONTACT_IMG_URL: creatorImageString] as [String : Any]
let childUpdates = ["\(creatorID)/\(contactID)/": infoForCreator,
"\(contactID)/\(creatorID)/": infoForContact
]
Constants.refs.databaseChatsLite.updateChildValues(childUpdates)
}
}
}
}
Alternative, you can keep a counter:
var creatorImageString: String = ""
var contactImageString: String = ""
var completedCount = 0;
ReadContactImage(contactID: contactID)
{
success in
if success
{
contactImageString = self.tempContactImg
completedCount++
if completedCount == 2
{
createDatabaseNode(contactImageString, creatorImageString)
}
}
}
ReadContactImage(contactID: creatorID)
{
success in
if success
{
creatorImageString = self.tempContactImg
completedCount++
if completedCount == 2
{
createDatabaseNode(contactImageString, creatorImageString)
}
}
}
And createDatabaseNode is then a function that contains your code to populates the data structures and calls updateChildValues.
Related
I need to initialize an object, and pass it through a prepareforsegue to another class.
Last line of the code below throws "Contextual type 'FPChat!.Type' cannot be used with dictionary literal"
if (segue.identifier == "chatmessages") {
let vc = segue.destination as! FPChatMessageViewController
//vc.currentChat = fPChat
}
}
fPchat = FPChat?
// Start the Chat
#IBAction func Chat(_ sender: UIButton) {
// Create a new entry in chats. This variable is passed with prepareforsegue
let chatRef = ref.child("chats").childByAutoId()
let chatId = chatRef.key
//fPchat = FPChat?
let fPchat = FPChat.currentChat(currentChatID: chatId)
Below chat class:
import Firebase
class FPChat {
var chatID = ""
var chatDate: Date!
var text = ""
var messages: [FPChatMessage]!
var author: FPUser!
var mine = true
// Calling FPChat.currentChat(id) I have back the FPChat object
static func currentChat(currentChatID: String) -> FPChat {
return FPChat(chatID: currentChatID)
}
private init(chatID: String) {
self.chatID = chatID
}
init(snapshot: DataSnapshot, andMessages messages: [FPChatMessage]) {
guard let value = snapshot.value as? [String: Any] else { return }
self.chatID = snapshot.key
if let text = value["text"] as? String {
self.text = text
}
guard let timestamp = value["timestamp"] as? Double else { return }
self.chatDate = Date(timeIntervalSince1970: (timestamp / 1_000.0))
guard let author = value["author"] as? [String: String] else { return }
self.author = FPUser(dictionary: author)
self.messages = messages
self.mine = self.author.userID == Auth.auth().currentUser?.uid
}
}
What I am doing wrong?
I have written the following function to search through my Firebase database and I have also looked into using debug statements and tested with breakpoints to see this function is pulling the correct data and it is. But when I return the array at the end, the array is empty. As far as I understand this is due to the asynchronous nature of firebase. The function is getting to the end before the data is being added to the array. How do I fix this so it can work as intended, I want to return an array of items which I can then use for other functions.
static func SearchPostsByTags(tags: [String]) -> [Post]{
var result = [Post]()
let dbref = FIRDatabase.database().reference().child("posts")
dbref.observeSingleEvent(of: .value, with: { snap in
let comps = snap.value as! [String : AnyObject]
for(_, value) in comps {
let rawTags = value["tags"] as? NSArray
let compTags = rawTags as? [String]
if compTags != nil {
for cTag in compTags! {
for tag in tags {
if (tag == cTag) {
let foundPost = Post()
foundPost.postID = value["postID"] as! String
foundPost.title = value["title"] as! String
result.append(foundPost)
}
}
}
}
}
})
return result
}
}
You are returning your array before the async call ends. You should fill your array inside the async call and call then another method, which provides the results.
static func SearchPostsByTags(tags: [String]) {
let dbref = FIRDatabase.database().reference().child("posts")
dbref.observeSingleEvent(of: .value, with: { snap in
let comps = snap.value as! [String : AnyObject]
var result = [Post]()
for(_, value) in comps {
let rawTags = value["tags"] as? NSArray
let compTags = rawTags as? [String]
if compTags != nil {
for cTag in compTags! {
for tag in tags {
if (tag == cTag) {
let foundPost = Post()
foundPost.postID = value["postID"] as! String
foundPost.title = value["title"] as! String
result.append(foundPost)
}
}
}
}
}
// Call some func to deliver the finished result array
// You can also work with completion handlers - if you want to try have a look at callbacks / completion handler section of apples documentation
provideTheFinishedArr(result)
})
}
people in my app sometimes needs to update the status of something. Now can you choose of 2 things: The so called "Rollerbank" is still there or the "Rollerbank" is removed. The users can create a data ref. The id that will be created by childbyAutoID. Now is my question how to get the right child and update some childs with a value. My post:
class Post {
let ref: DatabaseReference!
var TypeControle: String = ""
var Stad: String = ""
var Tijd: String = ""
var TijdControle: String = ""
var TijdControleniet: String = ""
var Latitude: String = ""
var Longitude: String = ""
var Extrainformatie: String = ""
var Staater: String = ""
var Staaternietmeer: String = ""
init(TypeControle: String) {
self.TypeControle = TypeControle
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(Stad: String){
self.Stad = Stad
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(Tijd: String) {
self.Tijd = Tijd
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(Latitude: String) {
self.Latitude = Latitude
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(Longitude: String) {
self.Longitude = Longitude
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(Extrainformatie: String) {
self.Extrainformatie = Extrainformatie
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(Staater: String) {
self.Staater = Staater
ref = Database.database().reference().child("Rollerbanken").child("Controletest").childByAutoId()
}
init(Staaternietmeer: String) {
self.Staaternietmeer = Staaternietmeer
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(TijdControle: String) {
self.TijdControle = TijdControle
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(TijdControleniet: String) {
self.TijdControleniet = TijdControleniet
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init() {
ref = Database.database().reference().child("Rollerbanken").childByAutoId()
}
init(snapshot: DataSnapshot)
{
ref = snapshot.ref
if let value = snapshot.value as? [String : Any] {
TypeControle = value["TypeControle"] as! String
Stad = value["Stad"] as! String
Tijd = value["Tijd"] as! String
Latitude = value["Latitude"] as! String
Longitude = value["Longitude"] as! String
Extrainformatie = value["Extrainformatie"] as! String
Staater = value["Staater"] as! String
Staaternietmeer = value["Staaternietmeer"] as! String
TijdControle = value["TijdControle"] as! String
TijdControleniet = value["TijdControleniet"] as! String
}
}
func save() {
ref.setValue(toDictionary())
}
func toDictionary() -> [String : Any]
{
return [
"TypeControle" : TypeControle,
"Stad" : Stad,
"Tijd" : Tijd,
"Latitude" : Latitude,
"Longitude" : Longitude,
"Extrainformatie" : Extrainformatie,
"Staater" : Staater,
"Staaternietmeer" : Staaternietmeer,
"TijdControle" : TijdControle,
"TijdControleniet" : TijdControleniet
]
}
}
Data for the TableViewCell:
class ControleTableViewCell: UITableViewCell {
#IBOutlet weak var storyControle: UILabel!
#IBOutlet weak var storyTijd: UILabel!
var post: Post! {
didSet {
storyControle.text = "\(post.Staaternietmeer)"
storyTijd.text = "\(post.TijdControleniet)"
storyControle.text = "\(post.Staater)"
storyTijd.text = "\(post.TijdControle)"
}
}
How my update button looks like:
#IBAction func Update(_ sender: Any) {
let alertController1 = UIAlertController(title: "Update melden" , message: "De rollerbank", preferredStyle: .alert)
// Create the actions
let RollerbankAction1 = UIAlertAction(title: "Staat er nog steeds", style: UIAlertActionStyle.default) {
UIAlertAction in
NSLog("Ja Pressed")
self.newStory.Staater = self.Staater
self.newStory.TijdControle = self.TijdControle
self.newStory.save()
}
let cancelAction1 = UIAlertAction(title: "Staat er niet meer", style: UIAlertActionStyle.cancel) {
UIAlertAction in
NSLog("Cancel Pressed")
let date = Date()
let calendar = Calendar.current
let hour = calendar.component(.hour, from: date)
let minutes = calendar.component(.minute, from: date)
let Tijd = "\(hour) : \(minutes)"
self.newStory.Staaternietmeer = self.Staaternietmeer
self.newStory.TijdControleniet = Tijd
self.newStory.save()
}
alertController1.addAction(RollerbankAction1)
alertController1.addAction(cancelAction1)
self.present(alertController1, animated: true, completion: nil)
}
This is the Structure that i use. If i run all this code, the new data will go in a other childbyAutoID and thats not what i want. It just needs to update/setvalue in the cleare space named "Staaternietmeer" and "TijdControleniet". Can anybody help me with that?
You would then need to store the Push ID somewhere so that you can reuse it later.
To generate a unique Push ID you would use :
Database.database().reference().childByAutoId()
And to store it somewhere :
let postKey = Database.database().reference().childByAutoId().key
And then, say you need a method to share a post for example, and want to add this post to multiple nodes, that's how it may look like :
func sharePost(_ postContent: String, completion: #escaping (Bool) -> ()) {
guard let currentUserId = Auth.auth().currentUser?.uid else {
completion(false)
return
}
let postKey = Database.database().reference().childByAutoId().key
let postData: [String: Any] = [ "content": "blabla",
"author": currentUserId ]
let childUpdates: [String: Any] = ["users/\(currentUserId)/posts/\(postKey)": true,
"posts/\(postKey)": postData ]
Database.database().reference().updateChildValues(childUpdates, withCompletionBlock: { (error, ref) in
guard error == nil else {
completion(false)
return
}
completion(true)
})
}
Now to access the unique Push ID later on, you would use :
Database.database().reference().observe(.childAdded, with: { (snapshot) in
// Here you get the Push ID back :
let postKey = snapshot.key
// And others things that you need :
guard let author = snapshot.childSnapshot(forPath: "author").value as? String else { return }
guard let content = snapshot.childSnapshot(forPath: "content").value as? String else { return }
// Here you store your object (Post for example) in an array, and as you can see you initialize your object using the data you got from the snapshot, including the Push ID (`postKey`) :
posts.append(Post(id: postKey, content: content, author: author))
})
I'm initializing some data in Firebase that I will use to track a user's activity. I need to make sure this data is written to Firebase so I'm wondering what the best practice is for ensuring a critical upload was successful?
static func createUserActivityCounts(uid: String) {
DispatchQueue.global(qos: .background).asyncAfter(deadline: .now() + .seconds(5)) {
let databaseReference = Database.database().reference()
let userCounts: [String: Any] = ["posts": 0,
"comments": 0,
"likes": 0]
databaseReference.child("userActivity").child(uid).child("counts").setValue(userCounts) { (error, ref) -> Void in
if error != nil {
print(error!.localizedDescription)
}
}
}
}
I think the best way to resolve this issue is to check if the value exists whenever you attempt to query a critical upload. If the value isn't there then you initialize it. Here is the function I wrote to handle this.
private func getUserActivityCounts() {
if let uid = Auth.auth().currentUser?.uid {
userRef.child("userActivity").child(uid).child("counts").observeSingleEvent(of: .value, with: { snap in
if !snap.exists() {
// create user counts
if let uid = Auth.auth().currentUser?.uid {
DatabaseFunctions.createUserActivityCounts(uid: uid)
}
}
if let counts = snap.value as? [String: Any] {
if let numberOfLikes = counts["likes"] as? Int, let commentCount = counts["comments"] as? Int, let postCount = counts["posts"] as? Int {
DispatchQueue.main.async {
self.headerRef.postCount.text = String(postCount)
self.headerRef.commentCount.text = String(commentCount)
self.headerRef.likeCount.text = String(numberOfLikes)
self.collectionView.reloadData()
}
self.numberOfUserPosts = postCount
self.commentCount = commentCount
self.likeCount = numberOfLikes
}
}
})
}
}
I'm using socket.io Swift Library. With the following line of code,
socket.on("info") { (dataArray, socketAck) -> Void in
let user = dataArray[0] as? User
print(user._id)
}
dataArray[0] is a valid object but user appears to be nil after casting.
Since dataArray[0] returns as an AnyObject,
how can i cast AnyObject to User Object?. Or somehow manage to do what i want with a different approach?
Since after this line
let user = dataArray[0] as? User
you have a nil value inside user it means that you don't have a User value at the first position of dataArray.
Since dataArray comes from a server (as I guess) it probably contains a serialized version of User.
Now we really need to know what really dataArray[0] is. However...
if dataArray[0] contains NSData
In this case try this
let json = JSON(dataArray[0] as! NSData)
let user = User(json:json)
You need to create a constructor that accept AnyObject and read data in it.
I guess in this case dataArray[0] is an JSON Object.
class User {
init(data: [String: AnyObject]) {
username = data["username"] as? String ?? ""
}
}
This is how i manage mine:
// Structure used as parameter
struct InfoStruct {
var nome: String = ""
var sobrenome:String = ""
var nascimentoTimestamp: NSNumber = 0
init() {
}
// Struct to AnyObject
func toAnyObject() -> Any {
var dic = [String:AnyObject?]()
if (nome != "") { dic["nome"] = nome as AnyObject }
if (sobrenome != "") { dic["sobrenome"] = sobrenome as AnyObject }
if (nascimentoTimestamp != 0) { dic["nascimentoTimestamp"] = nascimentoTimestamp as AnyObject }
return dic
}
// AnyObject to Struct
func fromAnyObject(dic:[String:AnyObject]) -> InfoStruct {
var retorno = InfoStruct()
if (dic["nome"] != nil) { retorno.nome = dic["nome"] as? String ?? "" }
if (dic["sobrenome"] != nil) { retorno.sobrenome = dic["sobrenome"] as? String ?? "" }
if (dic["nascimentoTimestamp"] != nil) { retorno.nascimentoTimestamp = dic["nascimentoTimestamp"] as? NSNumber ?? 0 }
return retorno
} }
// User class
class Usuario: NSObject {
var key: String
var admin: Bool
var info: InfoStruct // Struct parameter
init(_ key: String?) {
self.key = key ?? ""
admin = false
info = InfoStruct() // Initializing struct
}
// From Class to AnyObject
func toAnyObject() -> Any {
var dic = [String:AnyObject?]()
if (key != "") { dic["key"] = key as AnyObject }
if (admin != false) { dic["admin"] = admin as AnyObject }
dic["info"] = info.toAnyObject() as AnyObject // Struct
return dic
}
// From AnyObject to Class
func fromAnyObject(dic:[String:AnyObject]) -> Usuario {
let retorno = Usuario(dic["key"] as? String)
if (dic["key"] != nil) { retorno.key = dic["key"] as? String ?? "" }
if (dic["admin"] != nil) { retorno.admin = dic["admin"] as? Bool ?? false }
if (dic["info"] != nil) { retorno.info = InfoStruct.init().fromAnyObject(dic: dic["info"] as! [String : AnyObject]) } // Struct
return retorno
} }
// Using
let dao = FirebaseDAO.init(_type: FirebaseDAOType.firebaseDAOTypeUser)
dao.loadValue(key: uid) { (error, values:[String : AnyObject]) in
if error == nil {
let user = Usuario(values["key"] as? String).fromAnyObject(dic: values)
}
}
I hope it helps!