URLTask does not send any UrlRequest - swift

Question

I am new to swift and doing a project in swift 4.0 to acquire data form Fitbit API and got a Strange problem, my url task does not send any urlrequest any more but skip all the code until task.resume, and do not give anything back. Can anyone helps me plz. The code is shown below
import UIKit
class FitbitAPI{
static let sharedInstance : FitbitAPI = FitbitAPI()
var parsedJson : [Any]? = nil
func authorize(with token: String){
let accessToken = token
let baseURL = URL(string: "https://api.fitbit.com/1/user/-/activities/steps/date/today/1m.json")
let request = NSMutableURLRequest(url:baseURL!)
let bodydata = "access_token=\(String(describing: accessToken))"
request.httpMethod = "GET"
request.setValue("Bearer \(String(describing: accessToken))", forHTTPHeaderField: "Authorization")
request.httpBody = bodydata.data(using: String.Encoding.utf8)
let task = URLSession.shared.dataTask(with: request as URLRequest, completionHandler: {[weak self] (data, response, error) in
if let error = error {
print(error)
}
if let data = data, error == nil{
do {
self?.parsedJson = (try JSONSerialization.jsonObject(with: data, options: []) as? [Any] )
print(String(describing: self?.parsedJson))
}catch _{
print("Received not-well-formatted JSON")
}
}
if let response = response {
let httpResponse = response as! HTTPURLResponse
print("response code = \(httpResponse.statusCode)")
}
})
task.resume()
}
}

Answer 1

As #Larme implied in his comment, all of that code between the let task = line and the task.resume() line is a callback. Meaning it won't get called until the task completes. Put breakpoints inside of that callback (like on your if let error = error line), and see if they get hit.
ALso, your URL task is a local variable in this method. That means it's entirely possible that its getting released from memory right at the end of this method, before the callback can even be executed. You'll need a reference to the task outside of the method if you want to guarantee that it stays alive in memory long enough to hit the completion callback.