How to prevent WKWebView to repeatedly ask for permission to access location?

Question

I have a WKWebView in my app and when I start browsing www.google.com or any other website that requires location service, a pop up window appears, asking for t

Answer 1

Because I did not find solution how to avoid this stupid duplicate permission request I created swift class NavigatorGeolocation. The aim of this class is to override native JavaScript's navigator.geolocation API with custom one with 3 benefits:

1. Frontend/JavaScript developer use navigator.geolocation API by standard way without taking care that it is overriden and uses code invocation JS --> Swift on behind
2. Keep all logic outside of ViewController as much as possible
3. No more ugly and stupid duplicate permission request (1st for app and 2nd for webview):

@AryeeteySolomonAryeetey answered some solution but it is missing my first and second benefit. In his solution frontend developer have to add to JavaScript code specific code for iOS. I do not like this ugly platform addtions - I mean JavaScript function getLocation invoked from swift which is never used by web or android platform. I have hybrid app (web/android/ios) which uses webview on ios/android and I want to have only one identical HTML5 + JavaScript code for all platforms but I do not want to use huge solutions like Apache Cordova (formerly PhoneGap).

You can easily integrate NavigatorGeolocation class to your project - just create new swift file NavigatorGeolocation.swift, copy content from my answer and in ViewController.swift add 4 lines related to var navigatorGeolocation.

I think that Google's Android is much clever than Apple's iOS because webview in Android does not bother with duplicate permission request because permission is already granted/denied by user for app. There is no additional security to ask it twice as some people defend Apple.

ViewController.swift:

import UIKit
import WebKit

class ViewController: UIViewController, WKNavigationDelegate {

    var webView: WKWebView!;
    var navigatorGeolocation = NavigatorGeolocation();

    override func loadView() {
        super.loadView();
        let webViewConfiguration = WKWebViewConfiguration();
        navigatorGeolocation.setUserContentController(webViewConfiguration: webViewConfiguration);
        webView = WKWebView(frame:.zero , configuration: webViewConfiguration);
        webView.navigationDelegate = self;
        navigatorGeolocation.setWebView(webView: webView);
        view.addSubview(webView);
    }

    override func viewDidLoad() {
        super.viewDidLoad();
        let url = Bundle.main.url(forResource: "index", withExtension: "html", subdirectory: "webapp");
        let request = URLRequest(url: url!);
        webView.load(request);
    }

    func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
        webView.evaluateJavaScript(navigatorGeolocation.getJavaScripToEvaluate());
    }

}

NavigatorGeolocation.swift:

import WebKit
import CoreLocation

class NavigatorGeolocation: NSObject, WKScriptMessageHandler, CLLocationManagerDelegate {

    var locationManager = CLLocationManager();
    var listenersCount = 0;
    var webView: WKWebView!;

    override init() {
        super.init();
        locationManager.delegate = self;
    }

    func setUserContentController(webViewConfiguration: WKWebViewConfiguration) {
        let controller = WKUserContentController();
        controller.add(self, name: "listenerAdded");
        controller.add(self, name: "listenerRemoved");
        webViewConfiguration.userContentController = controller;
    }

    func setWebView(webView: WKWebView) {
        self.webView = webView;
    }

    func locationServicesIsEnabled() -> Bool {
        return (CLLocationManager.locationServicesEnabled()) ? true : false;
    }

    func authorizationStatusNeedRequest(status: CLAuthorizationStatus) -> Bool {
        return (status == .notDetermined) ? true : false;
    }

    func authorizationStatusIsGranted(status: CLAuthorizationStatus) -> Bool {
        return (status == .authorizedAlways || status == .authorizedWhenInUse) ? true : false;
    }

    func authorizationStatusIsDenied(status: CLAuthorizationStatus) -> Bool {
        return (status == .restricted || status == .denied) ? true : false;
    }

    func onLocationServicesIsDisabled() {
        webView.evaluateJavaScript("navigator.geolocation.helper.error(2, 'Location services disabled');");
    }

    func onAuthorizationStatusNeedRequest() {
        locationManager.requestWhenInUseAuthorization();
    }

    func onAuthorizationStatusIsGranted() {
        locationManager.startUpdatingLocation();
    }

    func onAuthorizationStatusIsDenied() {
        webView.evaluateJavaScript("navigator.geolocation.helper.error(1, 'App does not have location permission');");
    }

    func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
        if (message.name == "listenerAdded") {
            listenersCount += 1;

            if (!locationServicesIsEnabled()) {
                onLocationServicesIsDisabled();
            }
            else if (authorizationStatusIsDenied(status: CLLocationManager.authorizationStatus())) {
                onAuthorizationStatusIsDenied();
            }
            else if (authorizationStatusNeedRequest(status: CLLocationManager.authorizationStatus())) {
                onAuthorizationStatusNeedRequest();
            }
            else if (authorizationStatusIsGranted(status: CLLocationManager.authorizationStatus())) {
                onAuthorizationStatusIsGranted();
            }
        }
        else if (message.name == "listenerRemoved") {
            listenersCount -= 1;

            // no listener left in web view to wait for position
            if (listenersCount == 0) {
                locationManager.stopUpdatingLocation();
            }
        }
    }

    func locationManager(_ manager: CLLocationManager, didChangeAuthorization status: CLAuthorizationStatus) {
        // didChangeAuthorization is also called at app startup, so this condition checks listeners
        // count before doing anything otherwise app will start location service without reason
        if (listenersCount > 0) {
            if (authorizationStatusIsDenied(status: status)) {
                onAuthorizationStatusIsDenied();
            }
            else if (authorizationStatusIsGranted(status: status)) {
                onAuthorizationStatusIsGranted();
            }
        }
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        if let location = locations.last {
            webView.evaluateJavaScript("navigator.geolocation.helper.success('\(location.timestamp)', \(location.coordinate.latitude), \(location.coordinate.longitude), \(location.altitude), \(location.horizontalAccuracy), \(location.verticalAccuracy), \(location.course), \(location.speed));");
        }
    }

    func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
        webView.evaluateJavaScript("navigator.geolocation.helper.error(2, 'Failed to get position (\(error.localizedDescription))');");
    }

    func getJavaScripToEvaluate() -> String {
        let javaScripToEvaluate = """
            // management for success and error listeners and its calling
            navigator.geolocation.helper = {
                listeners: {},
                noop: function() {},
                id: function() {
                    var min = 1, max = 1000;
                    return Math.floor(Math.random() * (max - min + 1)) + min;
                },
                clear: function(isError) {
                    for (var id in this.listeners) {
                        if (isError || this.listeners[id].onetime) {
                            navigator.geolocation.clearWatch(id);
                        }
                    }
                },
                success: function(timestamp, latitude, longitude, altitude, accuracy, altitudeAccuracy, heading, speed) {
                    var position = {
                        timestamp: new Date(timestamp).getTime() || new Date().getTime(), // safari can not parse date format returned by swift e.g. 2019-12-27 15:46:59 +0000 (fallback used because we trust that safari will learn it in future because chrome knows that format)
                        coords: {
                            latitude: latitude,
                            longitude: longitude,
                            altitude: altitude,
                            accuracy: accuracy,
                            altitudeAccuracy: altitudeAccuracy,
                            heading: (heading > 0) ? heading : null,
                            speed: (speed > 0) ? speed : null
                        }
                    };
                    for (var id in this.listeners) {
                        this.listeners[id].success(position);
                    }
                    this.clear(false);
                },
                error: function(code, message) {
                    var error = {
                        PERMISSION_DENIED: 1,
                        POSITION_UNAVAILABLE: 2,
                        TIMEOUT: 3,
                        code: code,
                        message: message
                    };
                    for (var id in this.listeners) {
                        this.listeners[id].error(error);
                    }
                    this.clear(true);
                }
            };

            // @override getCurrentPosition()
            navigator.geolocation.getCurrentPosition = function(success, error, options) {
                var id = this.helper.id();
                this.helper.listeners[id] = { onetime: true, success: success || this.noop, error: error || this.noop };
                window.webkit.messageHandlers.listenerAdded.postMessage("");
            };

            // @override watchPosition()
            navigator.geolocation.watchPosition = function(success, error, options) {
                var id = this.helper.id();
                this.helper.listeners[id] = { onetime: false, success: success || this.noop, error: error || this.noop };
                window.webkit.messageHandlers.listenerAdded.postMessage("");
                return id;
            };

            // @override clearWatch()
            navigator.geolocation.clearWatch = function(id) {
                var idExists = (this.helper.listeners[id]) ? true : false;
                if (idExists) {
                    this.helper.listeners[id] = null;
                    delete this.helper.listeners[id];
                    window.webkit.messageHandlers.listenerRemoved.postMessage("");
                }
            };
        """;

        return javaScripToEvaluate;
    }

}