问题
now I'm working on an iOS application in Swift 4. Here I'm using Alamofire to integrate the API calls. I need to integrate the right way to auto-refresh the authentication token and retry the previous API calls. I'm storing the authentication token once I logged in successfully. So after login, in each API, I'm appending the token in the header part. And when if the token is expired I will get 401. That time I need to auto-refresh the authentication token and recall the same API again. How can I do that? I checked in the Stackoverflow, but I didn't get any solution.
Here's my API Call,
import Foundation
import Alamofire
import SwiftyJSON
class LoveltyAPI {
let loveltyURL = Bundle.main.object(forInfoDictionaryKey: "APIUrlString") as! String // Main URL
let buildVersion = Bundle.main.object(forInfoDictionaryKey: "CFBundleShortVersionString") as! String //infoDictionary?["CFBundleShortVersionString"] as AnyObject
weak var delegate:LoveltyProtocol?
func get_profile(app_user_id:String, token:String) {
let urlString = "\(loveltyURL)\(get_profile_string)?app_user_id=\(app_user_id)"
let headers = ["Content-Type":"application/json","X-Requested-With":"XMLHttpRequest", "Authentication":"Token \(token)"]
Alamofire.request(urlString, method: .get, encoding: JSONEncoding.default, headers: headers).responseJSON { response in
switch response.result {
case .success:
let swiftyJsonVar = JSON(response.result.value!)
switch response.response?.statusCode {
case 200, 201:
self.delegate?.getUserProfile!(response: swiftyJsonVar["data"].dictionaryObject as AnyObject)
case 401:
self.delegate?.tokenExpired(response: tokenExpired as AnyObject)
case 404:
self.delegate?.serviceError!(response: swiftyJsonVar["message"] as AnyObject)
case 422:
self.delegate?.serviceError!(response: swiftyJsonVar["error"] as AnyObject)
case 503:
self.delegate?.appDisabled(response: swiftyJsonVar.dictionaryObject as AnyObject)
default:
self.delegate?.serviceError!(response: self.serverError as AnyObject)
}
case .failure(let error):
self.delegate?.serviceError!(response: self.serverError as AnyObject)
}
}
}
}
Please help me. If you can explain with my code, it would be very nice.
回答1:
You need Alamofire RequestRetrier and RequestAdapter check here
This is some example that I have:
import UIKit
import Alamofire
class MyRequestAdapter: RequestAdapter, RequestRetrier {
private typealias RefreshCompletion = (_ succeeded: Bool, _ accessToken: String?) -> Void
private let lock = NSLock()
private var isRefreshing = false
private var requestsToRetry: [RequestRetryCompletion] = []
var accessToken:String? = nil
var refreshToken:String? = nil
static let shared = MyRequestAdapter()
private init(){
let sessionManager = Alamofire.SessionManager.default
sessionManager.adapter = self
sessionManager.retrier = self
}
func adapt(_ urlRequest: URLRequest) throws -> URLRequest {
var urlRequest = urlRequest
if let urlString = urlRequest.url?.absoluteString, urlString.hasPrefix(BASE_URL), !urlString.hasSuffix("/renew") {
if let token = accessToken {
urlRequest.setValue("Bearer \(token)", forHTTPHeaderField: "Authorization")
}
}
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 in
guard let strongSelf = self else { return }
strongSelf.lock.lock() ; defer { strongSelf.lock.unlock() }
if let accessToken = accessToken {
strongSelf.accessToken = accessToken
}
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 = "\(BASE_URL)token/renew"
Alamofire.request(urlString, method: .get, parameters: nil, encoding: JSONEncoding.default, headers: ["Authorization":"Bearer \(refreshToken!)"]).responseJSON { [weak self] response in
guard let strongSelf = self else { return }
if
let json = response.result.value as? [String: Any],
let accessToken = json["accessToken"] as? String
{
completion(true, accessToken)
} else {
completion(false, nil)
}
strongSelf.isRefreshing = false
}
}
}
My example is a little bit complex, but yes in general we have two important methods first one is adapt(_ urlRequest: URLRequest) throws -> URLRequest where we attaching the token, here I have custom logic where one of the services have should not attach this token as a header. The second method is func should(_ manager: SessionManager, retry request: Request, with error: Error, completion: @escaping RequestRetryCompletion) where I check what is the error code(in my example 401). And then I refresh my tokens with
private func refreshTokens(completion: @escaping RefreshCompletion)
In my case, I have refresh token and access token and when I call the service with refresh token I should not append my old access token in the header. I think this is not best practice but it was implemented from peopele that I don't know.
回答2:
@m1sh0's answer was extremely helpful to me. I'm just adding the missing detail the OP asked for in the comments: How do you make the Alamofire request so that it uses the Retrier and Adapter?
I basically used @m1sh0's example and called it like this:
var request_url = Constants.API_URL + "/path/to/resource"
let sessionManager = Alamofire.SessionManager.default
sessionManager.adapter = MyRequestAdapter.shared
sessionManager.request(request_url).validate().responseJSON { (response: DataResponse<Any>) in
switch(response.result) {
case .success(_):
print(response.result.value!)
completion(response.result.value!)
case .failure(_):
print(response.result.error!)
completion(response.result.error!)
break
}
}
Note that you need validate() in the request in order to get retried on failure. Without it, the response is just returned for completion. Also note there's a failure case in the response block for all non-401 errors, as they are presumed unrecoverable.
来源：https://stackoverflow.com/questions/56963748/alamofire-auto-refresh-token-and-retry-previous-api-call-in-ios-swift-4