Alamofire 5 Adapting and Retrying Requests - ios

Question

I am trying to implement my OAuth2 flow using Alamofire 5.0.0-beta.3. As i can see the documentation is still for Alamofire 4 as stated in the github page as well.
I am trying to make the Oauth2 handler following the documentation for Alamofire 4. As the class names are changed, I am completely lost while making it.
This is the code that i am following:
class OAuth2Handler: RequestAdapter, RequestRetrier {
private typealias RefreshCompletion = (_ succeeded: Bool, _ accessToken: String?, _ refreshToken: String?) -> Void
private let sessionManager: SessionManager = {
let configuration = URLSessionConfiguration.default
configuration.httpAdditionalHeaders = SessionManager.defaultHTTPHeaders
return SessionManager(configuration: configuration)
}()
private let lock = NSLock()
private var clientID: String
private var baseURLString: String
private var accessToken: String
private var refreshToken: String
private var isRefreshing = false
private var requestsToRetry: [RequestRetryCompletion] = []
// MARK: - Initialization
public init(clientID: String, baseURLString: String, accessToken: String, refreshToken: String) {
self.clientID = clientID
self.baseURLString = baseURLString
self.accessToken = accessToken
self.refreshToken = refreshToken
}
// MARK: - RequestAdapter
func adapt(_ urlRequest: URLRequest) throws -> URLRequest {
if let urlString = urlRequest.url?.absoluteString, urlString.hasPrefix(baseURLString) {
var urlRequest = urlRequest
urlRequest.setValue("Bearer " + accessToken, forHTTPHeaderField: "Authorization")
return urlRequest
}
return urlRequest
}
// MARK: - RequestRetrier
func should(_ manager: SessionManager, retry request: Request, with error: Error, completion: #escaping RequestRetryCompletion) {
lock.lock() ; defer { lock.unlock() }
if let response = request.task?.response as? HTTPURLResponse, response.statusCode == 401 {
requestsToRetry.append(completion)
if !isRefreshing {
refreshTokens { [weak self] succeeded, accessToken, refreshToken in
guard let strongSelf = self else { return }
strongSelf.lock.lock() ; defer { strongSelf.lock.unlock() }
if let accessToken = accessToken, let refreshToken = refreshToken {
strongSelf.accessToken = accessToken
strongSelf.refreshToken = refreshToken
}
strongSelf.requestsToRetry.forEach { $0(succeeded, 0.0) }
strongSelf.requestsToRetry.removeAll()
}
}
} else {
completion(false, 0.0)
}
}
// MARK: - Private - Refresh Tokens
private func refreshTokens(completion: #escaping RefreshCompletion) {
guard !isRefreshing else { return }
isRefreshing = true
let urlString = "\(baseURLString)/oauth2/token"
let parameters: [String: Any] = [
"access_token": accessToken,
"refresh_token": refreshToken,
"client_id": clientID,
"grant_type": "refresh_token"
]
sessionManager.request(urlString, method: .post, parameters: parameters, encoding: JSONEncoding.default)
.responseJSON { [weak self] response in
guard let strongSelf = self else { return }
if
let json = response.result.value as? [String: Any],
let accessToken = json["access_token"] as? String,
let refreshToken = json["refresh_token"] as? String
{
completion(true, accessToken, refreshToken)
} else {
completion(false, nil, nil)
}
strongSelf.isRefreshing = false
}
}
}
This is how to use this for alamofire 4:
let baseURLString = "https://some.domain-behind-oauth2.com"
let oauthHandler = OAuth2Handler(
clientID: "12345678",
baseURLString: baseURLString,
accessToken: "abcd1234",
refreshToken: "ef56789a"
)
let sessionManager = SessionManager()
sessionManager.adapter = oauthHandler
sessionManager.retrier = oauthHandler
let urlString = "\(baseURLString)/some/endpoint"
sessionManager.request(urlString).validate().responseJSON { response in
debugPrint(response)
}
This is the link i am following to implement this.
https://github.com/Alamofire/Alamofire/blob/master/Documentation/AdvancedUsage.md#adapting-and-retrying-requests

Answer 1

Look at something like this.
struct EnvironmentInterceptor: RequestInterceptor {
func adapt(_ urlRequest: URLRequest, for session: Session, completion: #escaping (Result<URLRequest>) -> Void) {
var adaptedRequest = urlRequest
guard let token = AtraqService.shared.user?.token.accessToken else {
completion(.success(adaptedRequest))
return
}
adaptedRequest.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
completion(.success(adaptedRequest))
}
func retry(_ request: Request, for session: Session, dueTo error: Error, completion: #escaping (RetryResult) -> Void) {
if let response = request.task?.response as? HTTPURLResponse, response.statusCode == 401 {
//get token
}
}
}
Then
Session(configuration: configuration, interceptor: EnvironmentInterceptor())
Finally
request().validate().response...

Answer 2

If Alamofire 5 is not intercepting (adapting or retrying) your requests for some reason, then just try to check the delegate signature out as described here.
func adapt(_ urlRequest: URLRequest, for session: Session, completion: #escaping (AFResult<URLRequest>) -> Void) {
var modifiedURLRequest = urlRequest
let apiToken = config.apiToken
modifiedURLRequest.setValue(apiToken, forHTTPHeaderField: Constants.apiTokenHeader)
completion(.success(modifiedURLRequest))
}
func retry(_ request: Request, for session: Session, dueTo error: Error, completion: #escaping (RetryResult) -> Void) {
completion(.doNotRetry)
}
Here's the difference (look at the signature):
func adapt(_ urlRequest: URLRequest, for session: Alamofire.Session, completion: #escaping (AFResult<URLRequest>) -> Void) {
var modifiedURLRequest = urlRequest
let apiToken = config.apiToken
modifiedURLRequest.setValue(apiToken, forHTTPHeaderField: Constants.apiTokenHeader)
completion(.success(modifiedURLRequest))
}
func retry(_ request: Alamofire.Request, for session: Alamofire.Session, dueTo error: Error, completion: #escaping (RetryResult) -> Void) {
completion(.doNotRetry)
}