WKWebView delegate not responding to delegate method call - ios

Question

I have a WKWebView that is used to present the login screen of my OAuth Identity provider.
import UIKit
import WebKit
protocol OAuth2WKWebViewDelegate: class {
func didReceiveAuthorizationCode(_ code: String) -> Void
func didRevokeSession() -> Void
}
class OAuth2WKWebViewController: UIViewController {
let targetUrl: URLComponents
let webView = WKWebView()
weak var delegate: OAuth2WKWebViewDelegate?
init(targetUrl: URLComponents) {
self.targetUrl = targetUrl
super.init(nibName: nil, bundle: nil)
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
override func viewDidLoad() {
super.viewDidLoad()
loadUrl()
}
}
extension OAuth2WKWebViewController: WKNavigationDelegate {
func loadUrl() {
guard let url = targetUrl.url else { return }
view = webView
webView.load(URLRequest(url: url))
webView.allowsBackForwardNavigationGestures = true
webView.navigationDelegate = self
}
func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: #escaping (WKNavigationActionPolicy) -> Void) {
if let url = navigationAction.request.url {
if url.scheme == "appdev", url.absoluteString.range(of: "code") != nil {
let urlParts = url.absoluteString.components(separatedBy: "?")
let code = urlParts[1].components(separatedBy: "code=")[1]
delegate?.didReceiveAuthorizationCode(code)
}
if url.absoluteString == "appdev://oauth-callback-after-sign-out" {
delegate?.didRevokeSession()
}
}
decisionHandler(.allow)
}
}
I also have an IdentityService I use to present this view and respond to it's success / error.
protocol IdentityServiceProtocol {
var hasValidToken: Bool { get }
func initAuthCodeFlow() -> Void
func renderOAuthWebView(forService service: IdentityEndpoint, queryitems: [String: String]) -> Void
func storeOAuthTokens(accessToken: String, refreshToken: String, completion: #escaping () -> Void) -> Void
func renderAuthView() -> Void
}
class IdentityService: IdentityServiceProtocol {
fileprivate var apiClient: APIClient
fileprivate var keyChainService: KeyChainService
init(apiClient: APIClient = APIClient(), keyChainService: KeyChainService = KeyChainService()) {
self.apiClient = apiClient
self.keyChainService = keyChainService
}
var hasValidToken: Bool {
return keyChainService.fetchSingleObject(withKey: "AccessToken") != nil
}
func initAuthCodeFlow() -> Void {
let queryItems = ["response_type": "code", "client_id": clientId, "redirect_uri": redirectUri, "state": state, "scope": scope]
renderOAuthWebView(forService: .auth(company: "benefex"), queryitems: queryItems)
}
func initRevokeSession() -> Void {
guard let refreshToken = keyChainService.fetchSingleObject(withKey: "RefreshToken") else { return }
let queryItems = ["refresh_token": refreshToken]
renderOAuthWebView(forService: .revokeSession(company: "benefex"), queryitems: queryItems)
}
func renderOAuthWebView(forService service: IdentityEndpoint, queryitems: [String: String]) -> Void {
guard let targetUrl = constructURLComponents(endPoint: service, queryItems: queryitems) else { return }
let webView = OAuth2WKWebViewController(targetUrl: targetUrl)
webView.delegate = self
UIApplication.shared.windows.first?.rootViewController = webView
}
func storeOAuthTokens(accessToken: String, refreshToken: String, completion: #escaping ()-> Void) -> Void {
let success = keyChainService.storeManyObjects(["AccessToken": accessToken, "RefreshToken": refreshToken])
guard success == true else { return }
completion()
}
func renderAuthView() -> Void {
UIApplication.shared.windows.first?.rootViewController = UINavigationController.init(rootViewController: AuthenticatedViewController())
}
}
extension IdentityService: OAuth2WKWebViewDelegate {
func didReceiveAuthorizationCode(_ code: String) {
apiClient.call(endpoint: IdentityEndpoint.accessToken(company: "benefex", code: code)) { [weak self] (response: OAuthTokenResponse) in
switch response {
case .success(let payload):
guard let accessToken = payload.accessToken, let refreshToken = payload.refreshToken else { return }
self?.storeOAuthTokens(accessToken: accessToken, refreshToken: refreshToken) { self?.renderAuthView() }
case .error:
// login failed for some reason
print("could not complete request for access token")
}
}
}
func didRevokeSession() {
print("This was called")
}
}
extension IdentityService {
fileprivate var state: String {
return generateState(withLength: 20)
}
fileprivate func constructURLComponents(endPoint: IdentityEndpoint, queryItems: [String: String]) -> URLComponents? {
var url = URLComponents(url: endPoint.baseUrl, resolvingAgainstBaseURL: false)
url?.path = endPoint.path
url?.queryItems = queryItems.map { URLQueryItem(name: $0.key, value: $0.value) }
return url
}
fileprivate func generateState(withLength len: Int) -> String {
let letters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
let length = UInt32(letters.count)
var randomString = ""
for _ in 0..<len {
let rand = arc4random_uniform(length)
let idx = letters.index(letters.startIndex, offsetBy: Int(rand))
let letter = letters[idx]
randomString += String(letter)
}
return randomString
}
}
extension IdentityService {
var clientId: String {
let envVar = ProcessInfo.processInfo.environment
guard let value = envVar["APP_CLIENT_ID"] else { fatalError("Missing APP_CLIENT_ID enviroment variable") }
return value
}
var redirectUri: String {
let envVar = ProcessInfo.processInfo.environment
guard let value = envVar["APP_REDIRECT_URI"] else { fatalError("Missing APP_REDIRECT_URI enviroment variable") }
return value
}
var scope: String {
let envVar = ProcessInfo.processInfo.environment
guard let value = envVar["APP_SCOPES"] else { fatalError("Missing APP_SCOPES enviroment variable") }
return value
}
}
The delegate?.didReceiveAuthorizationCode(code) is working.
However when delegate?.didRevokeSession() is called from the WebView, the identity service does not respond.
I added some console logs and can see my IdentityService is being de - init when I invoke the logout method.
I believe this is causing it to do nothing when the delegate method fires.
How can I ensure the delegate method is called still?

Answer 1

This came up when I was searching for answers to my issue - if you are using the 10.2 or 10.2.1 compiler - an issue was occurring for us when compiling in Release (instead of Debug) - where the delegate functions are not being called
The fix for us was to include #objc before all delegate function calls, IE
#objc func webView(_ webView: WKWebView, decidePolicyFor navigationAction: WKNavigationAction, decisionHandler: #escaping (WKNavigationActionPolicy) -> Void)
If you are in the same scenario - this should help