Alamofire Error Domain=NSURLErrorDomain Code=-999 "cancelled"

Question

I already have successfully got keychain for my token and passing it to AccessTokenAdapter class shown below. http127.0.0.1:8000/api2/projects/?format=json is passed as projectsURL.

    class AccessTokenAdapter: RequestAdapter {
        private let accessToken: String

        init(accessToken: String) {
            self.accessToken = accessToken
        }

        func adapt(_ urlRequest: URLRequest) throws -> URLRequest {
            var urlRequest = urlRequest
         //   print("JWT \(accessToken)")
            urlRequest.setValue("JWT \(accessToken)", forHTTPHeaderField: "Authorization")

            return urlRequest
        }
    }


    let sessionManager = SessionManager()
    sessionManager.adapter = AccessTokenAdapter(accessToken: self.keychain["token"]!)

    sessionManager.request(self.projectsURL, method: .get, encoding: JSONEncoding.default).responseJSON{ response in
        switch response.result {
        case .success:
            print("yey I made it")
        case .failure(let error):
            print(error)
        }
    }

however, from print(error), my Xcode shows error like Error Domain=NSURLErrorDomain Code=-999 "cancelled" UserInfo={NSErrorFailingURLKey=http://127.0.0.1:8000/api2/projects/?format=json, NSLocalizedDescription=cancelled, NSErrorFailingURLStringKey=http127.0.0.1:8000/api2/projects/?format=json}

Any ideas?
Alamofire 4.0
Keychain
Xcode 8.1
Swift3
Using JWT for authentication
Using Postman with header, key = "Authentication", value = "JWT (token generated here)" works fine

Answer 1

When you make sessionManager a let constant it won't live longer than the embracing it function, thus the session ends as soon as the manager is deallocated.

To fix this, make sessionManager live longer. For example in my case I made it a class property:

class NetworkRequest: {

   var sessionManager = Alamofire.SessionManager()

   ...

   func performRequest(_ call: APICall, customLink: String = "", parameters: Dictionary<String, Any> = ["":"" as Any]) {

        let sessionConfig = URLSessionConfiguration.default
        sessionConfig.timeoutIntervalForRequest = call.suggestedTimeout()
        sessionConfig.timeoutIntervalForResource = call.suggestedTimeout()
        sessionManager = Alamofire.SessionManager(configuration: sessionConfig)
        sessionManager.adapter = AccessTokenAdapter()

        sessionManager.request(urlString,
                      method: call.method(),
                      parameters: parameters,
                      encoding: call.chooseEncoding(),
                      headers: [:])
        .responseJSON
        { response in
          ...
        }

}

The solution might be different according to your situation, but the idea is to keep sessionManager alive until the network request ends.

Answer 2

self.getSessionManager()
                 .request(urlstring, 
                          method: methods, 
                          parameters: parameters, 
                          encoding: JSONEncoding.prettyPrinted, 
                          headers: Header
                  ).responseJSON(
                         queue: nil, 
                         options: JSONSerialization.ReadingOptions.allowFragments
) { (responseObject) in
 // response parsing code is here
}.session.finishTasksAndInvalidate() 

Just put the method of invalidate after task finish, means session.finishTasksAndInvalidate()

All works great.