Refresh Bearer Token and resume current API - ios

Question

I need to resume my WebService if my bearer token expire by http code 401 ,
below is my code.
When a 401 error occurs that means the Access Token has expired and I need to send a Refresh Token over to my server to obtain a new Access Token.
After getting a new Access Token I need to redo the previous request that got the 401 error.
Suppose I hit webservice1 and its give 401 http code , then new bearer token request will generate and the same API resume to work. How can I do it ?
import UIKit
import CryptoKit
class SharedWebService: NSObject {
static let sharedApiInstance = SharedWebService()
func generalApiMethod (parameter : NSDictionary ,completion: #escaping ((NSMutableArray?) -> Void))
{
var dashboarddata : NSMutableArray = NSMutableArray()
let urlString = String(format:"URL OF API HERE")
let url = URL(string: urlString)
guard let requestUrl = url else { fatalError() }
var request = URLRequest(url: requestUrl)
request.timeoutInterval = 60
let bearerToken = "current bearer token"
request.setValue(bearerToken, forHTTPHeaderField: "Authorization")
request.httpMethod = "GET"
request.setValue("application/json", forHTTPHeaderField: "Accept")
URLSession.shared.dataTask(with: request) {
(data, response, error) in
if let httpResponse = response as? HTTPURLResponse {
print(httpResponse.statusCode)
if httpResponse.statusCode == 401
{
// Refresh bearerToken get here
let bearerToken = self.getBearerTokenDevice() //fetch api to get new bearer token
return
}
}
guard error == nil else {
print(error!.localizedDescription);
DispatchQueue.main.async{
completion(dashboarddata)
}
return
}
guard let jsonData = data else { print("Empty data"); return }
if String(data: jsonData, encoding: String.Encoding.utf8) != nil
{
do {
let responseJSON = try? JSONSerialization.jsonObject(with: jsonData, options: [])
if let responseJSON = responseJSON as? [String: Any] {
//Success case do here reponse return
completion(dashboarddata)
}
}
}
}.resume()
}
func getBearerTokenDevice()-> String
{
//how to handle it
return "New bearer token from api fetch"
}
}

Answer 1

work arround is,
Always call Api at splah which fetches Bearer token from server, it will refresh the token every time user opens the app,
2.1 make Api call Queue to process Api calls (Use generics here)
2.2 if api is successfull, Ok. if not than call a special Api call yo get the token,
2.3 if after fetching the token, get last api from Api Queue and call it..
its just an idea, how i think, i think it will be done, might be different in your case
https://stevenpcurtis.medium.com/use-operationqueue-to-chain-api-calls-in-swift-71eefd6891ef
here is guide to make Api call chain