WebAuthenticator.android.cs

using System;
using System.Threading.Tasks;
using Android.Content;
#if __ANDROID_29__
using AndroidX.Browser.CustomTabs;
#else
using Android.Support.CustomTabs;
#endif

namespace Xamarin.Essentials
{
    public partial class WebAuthenticator
    {
        static TaskCompletionSource<WebAuthenticatorResult> tcsResponse = null;
        static Uri currentRedirectUri = null;

        internal static bool OnResume(Intent intent)
        {
            // If we aren't waiting on a task, don't handle the url
            if (tcsResponse?.Task?.IsCompleted ?? true)
                return false;

            if (intent?.Data == null)
            {
                tcsResponse.TrySetCanceled();
                return false;
            }

            try
            {
                var intentUri = new Uri(intent.Data.ToString());

                // Only handle schemes we expect
                if (!WebUtils.CanHandleCallback(currentRedirectUri, intentUri))
                {
                    tcsResponse.TrySetException(new InvalidOperationException($"Invalid Redirect URI, detected `{intentUri}` but expected a URI in the format of `{currentRedirectUri}`"));
                    return false;
                }

                tcsResponse?.TrySetResult(new WebAuthenticatorResult(intentUri));
                return true;
            }
            catch (Exception ex)
            {
                tcsResponse.TrySetException(ex);
                return false;
            }
        }

        static async Task<WebAuthenticatorResult> PlatformAuthenticateAsync(WebAuthenticatorOptions webAuthenticatorOptions)
        {
            var url = webAuthenticatorOptions?.Url;
            var callbackUrl = webAuthenticatorOptions?.CallbackUrl;
            var packageName = Platform.AppContext.PackageName;

            // Create an intent to see if the app developer wired up the callback activity correctly
            var intent = new Intent(Intent.ActionView);
            intent.AddCategory(Intent.CategoryBrowsable);
            intent.AddCategory(Intent.CategoryDefault);
            intent.SetPackage(packageName);
            intent.SetData(global::Android.Net.Uri.Parse(callbackUrl.OriginalString));

            // Try to find the activity for the callback intent
            if (!Platform.IsIntentSupported(intent, packageName))
                throw new InvalidOperationException($"You must subclass the `{nameof(WebAuthenticatorCallbackActivity)}` and create an IntentFilter for it which matches your `{nameof(callbackUrl)}`.");

            // Cancel any previous task that's still pending
            if (tcsResponse?.Task != null && !tcsResponse.Task.IsCompleted)
                tcsResponse.TrySetCanceled();

            tcsResponse = new TaskCompletionSource<WebAuthenticatorResult>();
            currentRedirectUri = callbackUrl;

            if (!(await StartCustomTabsActivity(url)))
            {
                // Fall back to opening the system-registered browser if necessary
                var urlOriginalString = url.OriginalString;
                var browserIntent = new Intent(Intent.ActionView, global::Android.Net.Uri.Parse(urlOriginalString));
                Platform.CurrentActivity.StartActivity(browserIntent);
            }

            return await tcsResponse.Task;
        }

        static async Task<bool> StartCustomTabsActivity(Uri url)
        {
            // Is only set to true if BindServiceAsync succeeds and no exceptions are thrown
            var success = false;
            var parentActivity = Platform.GetCurrentActivity(true);

            var customTabsActivityManager = CustomTabsActivityManager.From(parentActivity);
            try
            {
                if (await BindServiceAsync(customTabsActivityManager))
                {
                    var customTabsIntent = new CustomTabsIntent.Builder(customTabsActivityManager.Session)
                        .SetShowTitle(true)
                        .Build();

                    customTabsIntent.Intent.SetData(global::Android.Net.Uri.Parse(url.OriginalString));

                    if (customTabsIntent.Intent.ResolveActivity(parentActivity.PackageManager) != null)
                    {
                        WebAuthenticatorIntermediateActivity.StartActivity(parentActivity, customTabsIntent.Intent);
                        success = true;
                    }
                }
            }
            finally
            {
                try
                {
                    customTabsActivityManager.Client?.Dispose();
                }
                finally
                {
                }
            }

            return success;
        }

        static Task<bool> BindServiceAsync(CustomTabsActivityManager manager)
        {
            var tcs = new TaskCompletionSource<bool>();

            manager.CustomTabsServiceConnected += OnCustomTabsServiceConnected;

            if (!manager.BindService())
            {
                manager.CustomTabsServiceConnected -= OnCustomTabsServiceConnected;
                tcs.TrySetResult(false);
            }

            return tcs.Task;

            void OnCustomTabsServiceConnected(ComponentName name, CustomTabsClient client)
            {
                manager.CustomTabsServiceConnected -= OnCustomTabsServiceConnected;
                tcs.TrySetResult(true);
            }
        }
    }
}