How to change access token with refresh token when it expires? - ios

Question

I am doing an Alamofire request, and during login, it gives me access token and refresh token. After getting access token, I save it in keychain. Every 20 minutes the access token expires and I need to convert it to refresh token.
Below is the code of saving in keychain.
final class KeychainManager {
let keychain = Keychain(service: "com.app")
func saveToken(token: String) {
do {
try keychain.set(token, key: "accessToken")
} catch let error {
print(error)
}
}
func getAccessToken() -> String? {
let token = try? keychain.getString(accessTokenKey)
return token
}
}
And here is my Alamofire request
AF.upload(multipartFormData: { multiFormData in
for form in bodyKeyValue {
multiFormData.append(Data(form.sValue.utf8), withName: form.sKey)
}
}, to: url).responseData { response in
switch response.result {
case .success(_):
do {
let decodedData = try JSONDecoder().decode(LoginResponseBody.self, from: response.data!)
self.keychain.saveToken(token: decodedData.data.accessToken)
completion(.success(decodedData))
} catch {
completion(.failure(.serverError))
}
case .failure(_):
print("fail")
}
}
Now I don't know how to use , refresh token here, so when access token expires, it will be converted to refresh token. Does Alamofire have a function for that?

Answer 1

Generally as a good rule of thumb.
When your access token expires and you need to use the refresh token.
What you should do is:
When the app makes the API call and the token is no longer valid (IE: time to use refresh) , when the call fails here in the do block.
do {
let decodedData = try JSONDecoder().decode(LoginResponseBody.self, from: response.data!)
self.keychain.saveToken(token: decodedData.data.accessToken)
completion(.success(decodedData))
} catch {
completion(.failure(.serverError))
}
When the completionHandler(.failure(.serverError)) is triggered
You can make another call here to retrieve the refresh token/generate a new one. Either inside this function or in the viewController.
so in your app, when your function call returns completionHandler(.failure(.serverError)) , add the function call into the app(either in the failure block or inside the viewController, depending on your app and dev preference) on failure retrieve new access token/refresh token then make the same API called that failed.