How to check if the multipart upload was successful with alamofire image

Question

I am making a network call to upload an image to a backend server. Right now I am using the following to code. This code works perfectly in conditions where the internet is online.

// MARK: - PUT

    static func PUT(URL: String,
                    data: Data,
                    mimeType: String,
                    headers: [String: String]?) -> Promise<Void>
    {
        return Promise { fulfill, reject in

            let URL = try! URLRequest(url: URL, method: .put, headers: headers)

            Alamofire.upload(
                multipartFormData: { multipartFormData in

                    multipartFormData.append(InputStream.init(data: data), withLength: UInt64(data.count), name: "image", fileName: "file.png", mimeType: mimeType)
            },
            with: URL,
            encodingCompletion: { encodingResult in
                switch encodingResult {
                    case .success(let upload, _, _):
                    upload.responseJSON { response in

                        if response.result.value == nil {
                            fulfill()
                        }else {
                            reject(response.result.error!)
                        }
                    }
                    case .failure( _):
                    break
                }
            })
        }
    }
}

In case I put it on offline mode. It'll still execute the function and still fullfills() the promise. Even tho the network is offline. I think this is because it's checking if the encodingResult is succesful or not. NOt for the network call itself.

How am I able to check if the network call was successful or not? It's returning Void.

Import notes:

Server returns nill if we receive 200 code which means that have uploaded the image.

I don't understand this. First, you don't fulfill or reject in the case of `.failure`. I would have thought that you want to `reject`. Second, if the response was `.success` but there was no `value`, you're fulfilling the promise, but if you did get a `value`, you are rejecting. That seems backwards. — Rob, Mar 30 '17 at 01:39
The server returns "nil" if we have an 200 code. That's how it's setup. You are right that I need to add a reject in the .failure to but that doesn't change the situation. — , Mar 30 '17 at 01:42
How would you change the existing code? :) thanks for the tip btw — , Mar 30 '17 at 01:43

Rob · Accepted Answer · 2017-03-30T02:24:11.500

If you're going to use status codes to determine success or failure, you should add validate:

For example:

static func PUT(URL: String,
                data: Data,
                mimeType: String,
                headers: [String: String]?) -> Promise<Void> {
    return Promise { fulfill, reject in

        let URL = try! URLRequest(url: URL, method: .put, headers: headers)

        Alamofire.upload(
            multipartFormData: { multipartFormData in
                multipartFormData.append(data, withName: "image", fileName: "file.png", mimeType: mimeType)
        }, with: URL) { encodingResult in
            switch encodingResult {
            case .success(let upload, _, _):
                upload
                    .validate(statusCode: 200 ..< 300)
                    .responseJSON { response in
                        switch response.result {
                        case .success:
                            fulfill()
                        case .failure(let error):
                            reject(error)
                        }
                }
            case .failure(let error):
                reject(error)
            }
        }
    }
}

The above assumes that upon successful response, you'll also get JSON response. You might want to do some additional checking of value.

If you're not returning JSON upon success, then just use response, not responseJSON:

static func PUT(URL: String,
                data: Data,
                mimeType: String,
                headers: [String: String]?) -> Promise<Void> {
    return Promise { fulfill, reject in
        let URL = try! URLRequest(url: URL, method: .put, headers: headers)

        Alamofire.upload(
            multipartFormData: { multipartFormData in
                multipartFormData.append(data, withName: "image", fileName: "file.png", mimeType: mimeType)
        }, with: URL) { encodingResult in
            switch encodingResult {
            case .success(let upload, _, _):
                upload
                    .validate(statusCode: 200 ..< 300)
                    .response { response in
                        if let error = response.error {
                            reject(error)
                        } else {
                            fulfill()
                        }
                }
            case .failure(let error):
                reject(error)
            }
        }
    }
}

How to check if the multipart upload was successful with alamofire image

1 Answers1