PromiseKit - Optional promise with reload first promise - promisekit

Question

I read all documentation but I don't response my question with successfull.
I have this scenario
I call the authenticated api point
If the response is 200 to 299 I fullfill
If the response is 401 I call the api for refresh the token
If i refreshed the API token I need to re-call the first api point (for recovery the needed data).
Can you help me with this problem?
Thanks

Answer 1

Use recursion for you needs. Using PromiseKit you can do awesome things. See my flow with refresh token request below. I expect that the code below is self-documented.
// Define here your errors
enum MyErrors: Swift.Error {
case unauthorized
case unknown
}
// Here is your primary function for retrieving remote data
func fetchRemoteData() {
self.primaryRequest()
.then { data in
return self.parsePrimaryRequest(response: data)
}
.done { parsedResult in
// do something here if all chaining is success
}
.recover { primaryRequestError in // this is your case for refresh token
if case MyErrors.unauthorized = primaryRequestError { // if not authorized
self.refreshTokenRequest()
.then { data in
return self.parseRefreshToken(data: data)
}
.done { token in
// do someting with token, save it in secure store (keychain)
self.fetchRemoteData()
}
.catch { refreshTokenError in
// refresh token request has failed
}
}
else {
throw primaryRequestError
}
}
.catch { primaryRequestError in
// here if error during request
}
}
func primaryRequest() -> Promise<Data> {
return Promise { seal in
// here you execure the request
// ...
// ...
let responseData = Data() // here you get data from URLSessionTask etc
let yourRequestStatusCode = 401 // take status code
let successCodes = Array(200...299) // define success codes
let authorizationErrorCode = 401 // define status code which requires performing refresh token request
if successCodes.contains(yourRequestStatusCode) {
return seal.fulfill(responseData)
} else if yourRequestStatusCode == authorizationErrorCode {
throw MyErrors.unauthorized
} else {
throw MyErrors.unknown
}
}
}
func parsePrimaryRequest(response: Data) -> Promise<String> {
return Promise { seal in
// here you parse response
// ...
// ...
let parsedObject = "Awesome result"
seal.fulfill(parsedObject)
}
}
func refreshTokenRequest() -> Promise<Data> {
return Promise { seal in
// here you execure the request to refresh token
// ...
// ...
let responseData = Data() // here you get data from URLSessionTask etc
let yourRequestStatusCode = 401 // take status code
let successCodes = Array(200...299) // define success codes for refresh token request
if successCodes.contains(yourRequestStatusCode) {
return seal.fulfill(responseData)
} else {
throw MyErrors.unknown
}
}
}
func parseRefreshToken(data: Data) -> Promise<String> {
return Promise { seal in
// here you parse response
// ...
// ...
let parsedObject = "00000000-00000000-00000000-00000000"
seal.fulfill(parsedObject)
}
}