如何从该结构访问成功/失败案例？

Question

Using Alamofire v4.0, Alamofire.upload() using MultipartFormData has changed, but I can't find out how to get the success/error case with the enumeration returned in the closure (type is SessionManager.MultipartFormDataEncodingResult )

Looking into the SessionManager.MultipartFormDataEncodingResult struct, here is what I get:

public enum MultipartFormDataEncodingResult {
    case success(request: UploadRequest, streamingFromDisk: Bool, streamFileURL: URL?)
    case failure(Error)
}

Answer 1

So Xcode seems to have been super unhelpful here and autocompleted the initialiser for that enum rather than the case statement. You would want to do something similar to what you have for the .failure case:

switch encodingResult {
case .success(let request, let streamingFromDisk, let streamFileURL):
    // you can now access request, streamingFromDisk and streamFileURL in this scope
    ...
case .failure(let errorType):
    // you can now access errorType in this scope
    ...
}