Alamofire 5 request retrier

[riverbaymark]

Greetings,

I have a request. With all of the updates with Swift 5 and Alamofire, I was wondering if we might get an updated example of the retrier for Alamofire 5.

Thanks!

Mark

[ericlewis]

in Alamofire 5 you can pass along the retrier / adapter as part of the request.

The other change in Alamofire 5 is that the global Session is no longer mutable. So you must create a new Session with the adapter & retrier as parameters if you want this to be accessible per session, instead of per request. You can no longer change this on the fly in Session itself.

[delboy1978uk]

I refactored the example to work with v5 yesterday, hope this is of help to you

import Foundation
import OAuth2
import Alamofire

class OAuth2RetryHandler: RequestRetrier, RequestAdapter {
    
    let loader: OAuth2DataLoader

    init(oauth2: OAuth2) {
        loader = OAuth2DataLoader(oauth2: oauth2)
    }
    
    public typealias RequestRetryCompletion = (_ shouldRetry: Bool, _ timeDelay: TimeInterval) -> Void
    
    func retry(_ request: Request, for session: Session, dueTo error: Error, completion: @escaping (RetryResult) -> Void) {
       
        
        if let response = request.task?.response as? HTTPURLResponse, 401 == response.statusCode, let req = request.request {
            var dataRequest = OAuth2DataRequest(request: req, callback: { _ in })
          
            dataRequest.context = completion
            loader.enqueue(request: dataRequest)
            loader.attemptToAuthorize() { authParams, error in
                self.loader.dequeueAndApply() { req in
                    if let comp = req.context as? RequestRetryCompletion {
                        comp(nil != authParams, 0.0)
                    }
                }
            }
        }
        else {
             completion(.doNotRetry)   // not a 401, not our problem
        }
    }
    
    func adapt(_ urlRequest: URLRequest, for session: Session, completion: @escaping (Result<URLRequest, Error>) -> Void) {
        guard nil != loader.oauth2.accessToken else {
            completion(.success(urlRequest))
            return
        }
        
        do {
            let request = try urlRequest.signed(with: loader.oauth2)
            
            return completion(.success(request))
        } catch {
            print("Unable to sign request: \(error)")
            return completion(.failure(error))
        }
    }
}

[metaine]

RequestRetryCompletion has no place here since dataRequest.context type is (RetryResult) -> Void)

Change to self.loader.dequeueAndApply() { req in if let comp = req.context as? (RetryResult) -> Void { comp(nil != authParams ? .retry : .doNotRetry) } }

[delboy1978uk]

Thanks, I'm a n00b at Swift, but I will have a shot at refactoring it the next time I look at my project :-)

[metaine]

moreover, Alamofire 5 invokes two retry checks. One for validate() and another for serializer https://github.com/Alamofire/Alamofire/issues/2562 which effectively invokes oauth2.afterAuthorizeOrFail two times for every request that have both validate() and responseJSON (for example). I have no idea how to fix that at the moment.