How to Use Recursion to get all Files in a Directory Tree for Firebase Cloud Storage

Question

I've been playing around with Firebase Cloud Storage lately in Swift, and I've come across a scenario where I would like to retrieve images (and only images) in a "folder" (that has other sub folders in it) stored in the bucket. In other words, I want to use recursion to access the files nested in many folders.

I've seen examples done such as this, but of course, this is by using Swift's FileManager, so I won't be able to utilize the same feature on Firebase Cloud Storage.

Also, keep in mind that I don't want to have a hard-coded reference path such as storage.reference().child("Hard-coded path")

This is what I have so far without using recursion:

class FIRQueries {
    var storage: Storage
    var storageRef: StorageReference
    init() {
        storage = Storage.storage()
        storageRef = storage.reference()
    }
    func listFilesInCloud(completion: @escaping(Result<StorageListResult, Error>) -> ()) {
        self.storageRef.root().listAll { result, error in
        if let error = error {
            completion(.failure(error))
            print(error.localizedDescription)
            return
        } else {
            completion(.success(result))
            for prefix in result.prefixes {
                completion(.success(prefix.fullPath))
            }
            for item in result.items {
                print(item)
            }
        }
    }
}

and receiving the results in a SwiftUI .onAppear block

.onAppear {
        FIRQueries().listFilesInCloud { value in
            switch value {
            case .failure(let error):
                print(error)
                
            case .success(let result):
                for prefix in result.prefixes {
                    print(prefix.fullPath)
                }
            }
        }
}

Soo... is there any way to achieve this? With this code, I've only managed to get the names of the "folder" under the root of the bucket. I know I can set a child after self.storageRef.root() and give it a path, but then it'll be a hard-coded path.

Any help is appreciated! Thank you!

Answer 1

As the Firebase documentation on listing all files shows, you can call listAll(completion:) on each prefix to recursively.

So:

for prefix in result.prefixes {
    print(prefix.fullPath)
    prefix.listAll(...) //  List files in subdirectory
}