iOS Moya实现OAuth请求的方法

let oauth2 = OAuth2CodeGrant(settings: [
  "client_id": "my_swift_app",
  "client_secret": "C7447242",
  "authorize_uri": "https://github.com/login/oauth/authorize",
  "token_uri": "https://github.com/login/oauth/access_token",
  "redirect_uris": ["myapp://oauth/callback"],
  "scope": "user repo:status",
  "secret_in_body": true,
  "keychain": false,
] as OAuth2JSON)

import Foundation
import OAuth2
import Alamofire


class OAuth2RetryHandler: RequestRetrier, RequestAdapter {
  
  let loader: OAuth2DataLoader
  
  init(oauth2: OAuth2) {
    loader = OAuth2DataLoader(oauth2: oauth2)
  }
  
  /// Intercept 401 and do an OAuth2 authorization.
  public func should(_ manager: SessionManager, retry request: Request, with error: Error, completion: @escaping RequestRetryCompletion) {
    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(false, 0.0)  // not a 401, not our problem
    }
  }
  
  /// Sign the request with the access token.
  public func adapt(_ urlRequest: URLRequest) throws -> URLRequest {
    guard nil != loader.oauth2.accessToken else {
      return urlRequest
    }
    return try urlRequest.signed(with: loader.oauth2)  // "try" added in 3.0.2
  }
}

func getManager() -> SessionManager {

    let oauth2 = OAuth2CodeGrant(settings: [
      "client_id": "my_swift_app",
      "client_secret": "C7447242",
      "authorize_uri": "https://github.com/login/oauth/authorize",
      "token_uri": "https://github.com/login/oauth/access_token",
      "redirect_uris": ["myapp://oauth/callback"],
      "scope": "user repo:status",
      "secret_in_body": true,
      "keychain": false,
      ] as OAuth2JSON)

    let sessionManager = SessionManager()
    let oauthHandler = OAuth2Handler(oauth2: oauth2)
    sessionManager.adapter = oauthHandler
    sessionManager.retrier = oauthHandler
    return sessionManager
  }

fileprivate lazy var provider: MoyaProvider = {
  return MoyaProvider<API>(manager: self.getManager(),
              plugins: [NetworkLoggerPlugin()])
}()