How to call childByAutoId once in a loop? (Swift)

Question

Since I am uploading multiple images to firebase with one click I created a loop that goes until all the images are uploaded. Once I have uploaded the images to storage I want to save the urls in realtime firebase. This is what I have:

@IBAction func postFinalButton(_ sender: Any) {
        ProgressHUD.show()
        ProgressHUD.animationType = .circleRotateChase
        ProgressHUD.colorAnimation = #colorLiteral(red: 0.337254902, green: 0.6156862745, blue: 0.9803921569, alpha: 1)
        ProgressHUD.colorHUD = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 0)
        startUploading(completion: {
            print("Done!!!")
            ProgressHUD.showSucceed()
        })
    }
    func sendDataToDatabase(photoUrl: String, ref: DatabaseReference, index: Int) {
     print("okbud")
      let name = "photoUrl"+String(index)
        ref.setValue([name: photoUrl, "caption": "buddy"], withCompletionBlock: {
        (error, ref) in
        if error != nil {
            ProgressHUD.showError(error?.localizedDescription)
            return
        }
        ProgressHUD.showSucceed()
      })
    }
    func startUploading(completion: @escaping FileCompletionBlock) {
         if ImagesOnClick.count == 0 {
            completion()
            return;
         }

         block = completion
         uploadImage(forIndex: 0)
    }

    func uploadImage(forIndex index:Int) {
        let ref = Database.database().reference()
        let postsReference = ref.child("posts")
        let newImagesRef = postsReference.childByAutoId()

         if index < ImagesOnClick.count {
              /// Perform uploading
             let data = ImagesOnClick[index]!.pngData()
             let fileName = String(format: "%@.png", String(newImagesRef.key!))

            FirFile.shared.upload(data: data!, withName: fileName, block: { (url) in
                  /// After successfully uploading call this method again by increment the **index = index + 1**
                  print(url ?? "Couldn't not upload. You can either check the error or just skip this.")
                  self.sendDataToDatabase(photoUrl: url!, ref: newImagesRef, index: index)
                  self.uploadImage(forIndex: index + 1)
               })
            return;
          }

          if block != nil {
             block!()
          }
    }
    
class FirFile: NSObject {

    /// Singleton instance
    static let shared: FirFile = FirFile()

    /// Path
    let kFirFileStorageRef = Storage.storage().reference(forURL: "gs://loginpage-227bd.appspot.com")

    /// Current uploading task
    var currentUploadTask: StorageUploadTask?

    func upload(data: Data,
                withName fileName: String,
                block: @escaping (_ url: String?) -> Void) {

        // Create a reference to the file you want to upload
        let fileRef = kFirFileStorageRef.child(fileName)

        /// Start uploading
        upload(data: data, withName: fileName, atPath: fileRef) { (url) in
            block(url)
        }
    }
    func upload(data: Data,
                withName fileName: String,
                atPath path:StorageReference,
                block: @escaping (_ url: String?) -> Void) {

        // Upload the file to the path
        self.currentUploadTask = path.putData(data, metadata: nil) { (metaData, error) in
             guard let metadata = metaData else {
                  // Uh-oh, an error occurred!
                  block(nil)
                  return
             }
             // Metadata contains file metadata such as size, content-type.
             // let size = metadata.size
             // You can also access to download URL after upload.
             path.downloadURL { (url, error) in
                  guard let downloadURL = url else {
                     // Uh-oh, an error occurred!
                     block(nil)
                     return
                  }
                 block(downloadURL.absoluteString)
             }
        }
    }

    func cancel() {
        self.currentUploadTask?.cancel()
    }
}
}

However the images get stored like this: When I want them to be stored like this:

How would I do this?

Answer 1

I declared a varaible:

var childByAutoId = String()

Then when the viewDidLoad I assigned the function childByAutoId() to the variable childByAutoId

        let ref = Database.database().reference()
        let postsReference = ref.child("posts")
        let newImagesRef = postsReference.childByAutoId()
        childByAutoId = newImagesRef.key!

And finally:

        let ref = Database.database().reference()
        let postsReference = ref.child("posts")
        let newImagesRef = postsReference.child(childByAutoId)

self.sendDataToDatabase(photoUrl: url!, ref: newImagesRef, index: index)

Comment if you have any questions!