IdentityServer4 helper for swift 4

IdentityServerHelper.swift

//
//  IdentityServerHelper.swift
//  Example
//
// Aimore Sa on 5/6/19.
//

import Foundation
import AppAuth

//protocol Auth {
//    func getAuthToken(viewController: UIViewController) -> String
//    func getUserInfo() -> UserInfo
//    //TODO add clear Auth function
//}

struct AuthConstants{
    private(set) static var issuer: String = "https://demo.identityserver.io"
    private(set) static var  auhtClientId: String = "native.code"
    private(set) static var  redirectUri: String = "com.example.app:/oauth2redirect/example-provider"
    private(set) static var appAuthExampleAuthStateKey: String = "authState";
//    static let redirectUri: String = "com.example.app:/oauth2redirect/example-provider"
}

struct UserInfo {
    var userName: String?
    var userSub: String?
    var authToken: String?
    var bearerToken: String?
}

class IdentityServerHelper : UIViewController {
    
    typealias PostRegistrationCallback = (_ configuration: OIDServiceConfiguration?, _ registrationResponse: OIDRegistrationResponse?) -> Void
    private var authState: OIDAuthState?
    var accessToken : String = ""
    private var user : UserInfo?
    
    func getAuthToken(viewController: UIViewController) -> String {
        guard let issuer = URL(string: AuthConstants.issuer) else {
            print("Error creating URL for : \(AuthConstants.issuer)")
            return ""
        }
        
        print("Fetching configuration for issuer: \(issuer)")
        
        // discovers endpoints
        OIDAuthorizationService.discoverConfiguration(forIssuer: issuer) { configuration, error in
            
            guard let config = configuration else {
                print("Error retrieving discovery document: \(error?.localizedDescription ?? "DEFAULT_ERROR")")
                self.setAuthState(nil)
                return
            }
            
            print("Got configuration: \(config)")
            self.doAuthWithAutoCodeExchange(configuration: config, clientID: AuthConstants.auhtClientId, clientSecret: nil, controller: viewController)
        }
        return self.accessToken
    }
    
    func getUserInfo() -> UserInfo {
        let user = UserInfo(userName: "zeca", userSub: "1202HS", authToken: "T3891414iqy4iqy4iq4yqi4ybj?", bearerToken: "kdfnkawgr3ety4q3j4gjqgf4jqv4jqgj4qg4jqg4j")
        return user
    }
    
    //MARK get user info and bearer token
    func userInfo() {
        guard let userinfoEndpoint = self.authState?.lastAuthorizationResponse.request.configuration.discoveryDocument?.userinfoEndpoint else {
            print("Userinfo endpoint not declared in discovery document")
            return
        }
        
        print("Performing userinfo request")
        
        let currentAccessToken: String? = self.authState?.lastTokenResponse?.accessToken
        
        self.authState?.performAction() { (accessToken, idTOken, error) in
            
            if error != nil  {
                print("Error fetching fresh tokens: \(error?.localizedDescription ?? "ERROR")")
                return
            }
            
            guard let accessToken = accessToken else {
                print("Error getting accessToken")
                return
            }
            
            if currentAccessToken != accessToken {
                print("Access token was refreshed automatically (\(currentAccessToken ?? "CURRENT_ACCESS_TOKEN") to \(accessToken))")
            } else {
                print("Access token was fresh and not updated \(accessToken)")
            }
            
            var urlRequest = URLRequest(url: userinfoEndpoint)
            urlRequest.allHTTPHeaderFields = ["Authorization":"Bearer \(accessToken)"]
            
            let task = URLSession.shared.dataTask(with: urlRequest) { data, response, error in
                
                DispatchQueue.main.async {
                    
                    guard error == nil else {
                        print("HTTP request failed \(error?.localizedDescription ?? "ERROR")")
                        return
                    }
                    
                    guard let response = response as? HTTPURLResponse else {
                        print("Non-HTTP response")
                        return
                    }
                    
                    guard let data = data else {
                        print("HTTP response data is empty")
                        return
                    }
                    
                    var json: [AnyHashable: Any]?
                    
                    do {
                        json = try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any]
                    } catch {
                        print("JSON Serialization Error")
                    }
                    
                    if response.statusCode != 200 {
                        // server replied with an error
                        let responseText: String? = String(data: data, encoding: String.Encoding.utf8)
                        
                        if response.statusCode == 401 {
                            // "401 Unauthorized" generally indicates there is an issue with the authorization
                            // grant. Puts OIDAuthState into an error state.
                            let oauthError = OIDErrorUtilities.resourceServerAuthorizationError(withCode: 0,
                                                                                                errorResponse: json,
                                                                                                underlyingError: error)
                            self.authState?.update(withAuthorizationError: oauthError)
                            print("Authorization Error (\(oauthError)). Response: \(responseText ?? "RESPONSE_TEXT")")
                        } else {
                            print("HTTP: \(response.statusCode), Response: \(responseText ?? "RESPONSE_TEXT")")
                        }
                        
                        return
                    }
                    
                    if let json = json {
                        print("Success: \(json)")
                    }
                }
            }
            task.resume()
        }
    }

    //MARK manual AUth without code exchange
    func doAuthWithoutCodeExchange(configuration: OIDServiceConfiguration, clientID: String, clientSecret: String?, viewController: UIViewController) {
        
        guard let redirectURI = URL(string: kRedirectURI) else {
            print("Error creating URL for : \(AuthConstants.redirectUri)")
            return
        }
        
        guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
            print("Error accessing AppDelegate")
            return
        }
        
        // builds authentication request
        let request = OIDAuthorizationRequest(configuration: configuration,
                                              clientId: clientID,
                                              clientSecret: clientSecret,
                                              scopes: [OIDScopeOpenID, OIDScopeProfile],
                                              redirectURL: redirectURI,
                                              responseType: OIDResponseTypeCode,
                                              additionalParameters: nil)
        
        // performs authentication request
        print("Initiating authorization request with scope: \(request.scope ?? "DEFAULT_SCOPE")")
        
        appDelegate.currentAuthorizationFlow = OIDAuthorizationService.present(request, presenting: viewController) { (response, error) in
            
            if let response = response {
                let authState = OIDAuthState(authorizationResponse: response)
                self.setAuthState(authState)
                print("Authorization response with code: \(response.authorizationCode ?? "DEFAULT_CODE")")
                // could just call [self tokenExchange:nil] directly, but will let the user initiate it.
            } else {
                print("Authorization error: \(error?.localizedDescription ?? "DEFAULT_ERROR")")
            }
        }
    }
    
    //MARK Auto exchange token need to pass UIViewController as parameter!
    func doAuthWithAutoCodeExchange(configuration: OIDServiceConfiguration, clientID: String, clientSecret: String?, controller: UIViewController) {
        
        guard let redirectURI = URL(string: AuthConstants.redirectUri) else {
            print("Error creating URL for : \(AuthConstants.redirectUri)")
            return
        }
        
        guard let appDelegate = UIApplication.shared.delegate as? AppDelegate else {
            print("Error accessing AppDelegate")
            return
        }
        
        // builds authentication request
        let request = OIDAuthorizationRequest(configuration: configuration,
                                              clientId: clientID,
                                              clientSecret: clientSecret,
                                              scopes: [OIDScopeOpenID, OIDScopeProfile],
                                              redirectURL: redirectURI,
                                              responseType: OIDResponseTypeCode,
                                              additionalParameters: nil)
        
        // performs authentication request
        print("Initiating authorization request with scope: \(request.scope ?? "DEFAULT_SCOPE")")
        
        appDelegate.currentAuthorizationFlow = OIDAuthState.authState(byPresenting: request, presenting: controller) {
            authState, error in
            if let authState = authState {
                self.setAuthState(authState)
                print("Got authorization tokens. Access token: \(authState.lastTokenResponse?.accessToken ?? "DEFAULT_TOKEN")")
                self.accessToken = authState.lastTokenResponse?.accessToken ?? ""
            } else {
                print("Authorization error: \(error?.localizedDescription ?? "DEFAULT_ERROR")")
                self.setAuthState(nil)
            }
        }
    }
    
    
    //MARK init functions
    func validateOAuthConfiguration() {
    
                assert(AuthConstants.appAuthExampleAuthStateKey == "authState")
        
                assert(AuthConstants.issuer == "https://demo.identityserver.io");
        
                assert(AuthConstants.auhtClientId == "native.code");
        
                assert(AuthConstants.redirectUri == "io.identityserver.demo:/oauthredirect");
        
        // verifies that the custom URI scheme has been updated in the Info.plist
        guard let urlTypes: [AnyObject] = Bundle.main.object(forInfoDictionaryKey: "CFBundleURLTypes") as? [AnyObject], urlTypes.count > 0 else {
            assertionFailure("No custom URI scheme has been configured for the project.")
            return
        }
        
        guard let items = urlTypes[0] as? [String: AnyObject],
            let urlSchemes = items["CFBundleURLSchemes"] as? [AnyObject], urlSchemes.count > 0 else {
                assertionFailure("No custom URI scheme has been configured for the project.")
                return
        }
        
        guard let urlScheme = urlSchemes[0] as? String else {
            assertionFailure("No custom URI scheme has been configured for the project.")
            return
        }
        
        assert(urlScheme != "com.example.app")
    }
    
    func loadState() {
        guard let data = UserDefaults.standard.object(forKey: kAppAuthExampleAuthStateKey) as? Data else {
            return
        }
        
        if let authState = NSKeyedUnarchiver.unarchiveObject(with: data) as? OIDAuthState {
            self.setAuthState(authState)
        }
    }
    
    func setAuthState(_ authState: OIDAuthState?) {
        if (self.authState == authState) {
            return;
        }
        self.authState = authState;
//        self.authState?.stateChangeDelegate = (self as OIDAuthStateChangeDelegate);
        self.stateChanged()
    }
    
    func saveState() {
        
        var data: Data? = nil
        
        if let authState = self.authState {
            data = NSKeyedArchiver.archivedData(withRootObject: authState)
        }
        
        UserDefaults.standard.set(data, forKey: kAppAuthExampleAuthStateKey)
        UserDefaults.standard.synchronize()
    }
    
    func stateChanged() {
        self.saveState()
    }
}

class test : UIViewController {
    override func viewDidLoad() {
        print("aaa")
    }
}

//MARK: OIDAuthState Delegate
extension IdentityServerHelper : OIDAuthStateChangeDelegate, OIDAuthStateErrorDelegate {

    func didChange(_ state: OIDAuthState) {
//        self.stateChanged()
    }

    func authState(_ state: OIDAuthState, didEncounterAuthorizationError error: Error) {
        print("Received authorization error: \(error)")
    }
}

TODO: save tokens in Keychain