Trouble implementing FileProvider

Hello,

I try to implement a FileProvider for iOS11.

I succeed to list my items, but when I try to show a file by clicking on it, nothing happens.

I set my item with this parameter :

var isDownloaded: Bool {
        if let file = self.file {
            if FileManager().fileExists(atPath: Tools().getGenericFilePath(file: file).path) {
                return true
            } else {
                return false
            }
        }
        return false
    }

(If I don't set it, it shows me the placeholder)

It seems that :

providePlaceholder(at url: URL, completionHandler: ((_ error: Swift.Error?) -> Void)?)

is called multiple times (at least three).

Here is my enumerator :

override func enumerator(for containerItemIdentifier: NSFileProviderItemIdentifier) throws -> NSFileProviderEnumerator {
   
        let maybeEnumerator: NSFileProviderEnumerator? = nil
        if (containerItemIdentifier == NSFileProviderItemIdentifier.rootContainer) {
            return FileProviderEnumerator(enumeratedItemIdentifier: containerItemIdentifier)
        } else if (containerItemIdentifier == NSFileProviderItemIdentifier.workingSet) {
            // TODO and never called
        } else {
            if (containerItemIdentifier.rawValue.starts(with: "F-")) {
                // if my item is a folder
                return FileProviderEnumerator(enumeratedItemIdentifier: containerItemIdentifier)
            } else if (containerItemIdentifier.rawValue.starts(with: "f-")) {
               // if my item is a file
                self.startProvidingItem(at: self.urlForItem(withPersistentIdentifier: containerItemIdentifier)!, completionHandler: { error in
                    if let error = error {
                        print(error)
                    }
                })
                return FileProviderEnumerator(enumeratedItemIdentifier: containerItemIdentifier)
            }
        }
        guard let enumerator = maybeEnumerator else {
            throw NSError(domain: NSCocoaErrorDomain, code: NSFeatureUnsupportedError, userInfo:[:])
        }
        return enumerator
    }

Here is my startProvidingItem which is not called :

override func startProvidingItem(at url: URL, completionHandler: ((_ error: Swift.Error?) -> Void)?) {
     
        let pathComponents = url.pathComponents
     
        assert(pathComponents.count > 1)
        var explodedPath = pathComponents[pathComponents.count - 1].characters.split(separator: ".").map(String.init)
        if fileManager.fileExists(atPath: url.path) {
            completionHandler!(nil)
        } else {
            if let file = CoreDataStore.sharedInstance.getFileByHash(explodedPath[0], privateMoc: false) {
                let sessionConfig = URLSessionConfiguration.ephemeral
                let session = URLSession(configuration: sessionConfig)
                guard let request = FolderRouter.downloadFile(file.remoteID).URLRequest else {
                    return
                }
                let task = session.dataTask(with: request) { (data, response, error) -> Void in
                 
                    DispatchQueue.main.async {
                        if let data = data {
                            self.fileManager.createFile(atPath: url.absoluteString, contents: data, attributes: nil)
                            completionHandler!(nil)
                         
                        }
                    }
                }
                task.resume()
                NSFileProviderManager.default.register(task, forItemWithIdentifier: persistentIdentifierForItem(at: url)!, completionHandler: { error in
                    if let error = error {
                        print(error)
                    }
                })
             
            } else {
                completionHandler?(NSError(domain: NSCocoaErrorDomain, code: NSFeatureUnsupportedError, userInfo:[:]))
            }
        }
    }

Any idea what I'm missing or doing wrong ?