Getting an error when trying to upload image to firebase (Swift)

Question

I have the following code:

func upload() {
        let localFile = usersImg!

        // Create the file metadata
        let metadata = StorageMetadata()
        metadata.contentType = "image/jpeg"
        let storageRef = Storage.storage().reference()

        // Upload file and metadata to the object 'images/mountains.jpg'
        let uploadTask = storageRef.putFile(from: localFile, metadata: metadata)

        // Listen for state changes, errors, and completion of the upload.
        uploadTask.observe(.resume) { snapshot in
          // Upload resumed, also fires when the upload starts
        }

        uploadTask.observe(.pause) { snapshot in
          // Upload paused
        }

        uploadTask.observe(.progress) { snapshot in
          // Upload reported progress
          let percentComplete = 100.0 * Double(snapshot.progress!.completedUnitCount)
            / Double(snapshot.progress!.totalUnitCount)
        }

        uploadTask.observe(.success) { snapshot in
          // Upload completed successfully
        }

        uploadTask.observe(.failure) { snapshot in
            if let error = snapshot.error as NSError? {
            switch (StorageErrorCode(rawValue: error.code)!) {
            case .objectNotFound:
              // File doesn't exist
              break
            case .unauthorized:
              // User doesn't have permission to access file
              break
            case .cancelled:
              // User canceled the upload
              break

            /* ... */

            case .unknown:
              // Unknown error occurred, inspect the server response
              break
            default:
              // A separate error occurred. This is a good place to retry the upload.
              break
            }
          }
        }
            
    }

The userImg variable is just the image the user selected, if I were to print it out it would look something like this:

Optional(file:///var/mobile/Media/DCIM/100APPLE/IMG_0030.PNG)

However when I run my code and call the method I get the following error:

Thread 12: "*** -[__NSPlaceholderDictionary initWithObjects:forKeys:count:]: attempt to insert nil object from objects[1]"

What does that mean and what am I doing wrong. (By the way I have tried a lot of different methods to upload urls to firebase but with everyone I am getting weird errors so this code is straight from firebase website.

Answer 1

I cannot guarantee anything because I didn't use this same code although I had to change the rules for my firebase storage and that helped!