Spent the last two days figuring this out myself. The library does not refresh the tokens automatically unless you specify “access_type=offline”.
https://developers.google.com/api-client-library/dotnet/guide/aaa_oauth
I’m gonna paste the code I’m using and if there is anything you don’t understand, just ask. I have read so many posts and I litteraly got this working right now so there is some commented code and it has not been refactored yet. I hope this will help someone. The NuGet packages I’m using are these:
Google.Apis.Auth.MVC
Google.Apis.Calendar.v3
Code:
AuthCallbackController:
[AuthorizationCodeActionFilter]
public class AuthCallbackController : Google.Apis.Auth.OAuth2.Mvc.Controllers.AuthCallbackController
{
protected static readonly ILogger Logger = ApplicationContext.Logger.ForType<AuthCallbackController>();
/// <summary>Gets the authorization code flow.</summary>
protected IAuthorizationCodeFlow Flow { get { return FlowData.Flow; } }
/// <summary>
/// Gets the user identifier. Potential logic is to use session variables to retrieve that information.
/// </summary>
protected string UserId { get { return FlowData.GetUserId(this); } }
/// <summary>
/// The authorization callback which receives an authorization code which contains an error or a code.
/// If a code is available the method exchange the coed with an access token and redirect back to the original
/// page which initialized the auth process (using the state parameter).
/// <para>
/// The current timeout is set to 10 seconds. You can change the default behavior by setting
/// <see cref="System.Web.Mvc.AsyncTimeoutAttribute"/> with a different value on your controller.
/// </para>
/// </summary>
/// <param name="authorizationCode">Authorization code response which contains the code or an error.</param>
/// <param name="taskCancellationToken">Cancellation token to cancel operation.</param>
/// <returns>
/// Redirect action to the state parameter or <see cref="OnTokenError"/> in case of an error.
/// </returns>
[AsyncTimeout(60000)]
public async override Task<ActionResult> IndexAsync(AuthorizationCodeResponseUrl authorizationCode,
CancellationToken taskCancellationToken)
{
if (string.IsNullOrEmpty(authorizationCode.Code))
{
var errorResponse = new TokenErrorResponse(authorizationCode);
Logger.Info("Received an error. The response is: {0}", errorResponse);
Debug.WriteLine("Received an error. The response is: {0}", errorResponse);
return OnTokenError(errorResponse);
}
Logger.Debug("Received \"{0}\" code", authorizationCode.Code);
Debug.WriteLine("Received \"{0}\" code", authorizationCode.Code);
var returnUrl = Request.Url.ToString();
returnUrl = returnUrl.Substring(0, returnUrl.IndexOf("?"));
var token = await Flow.ExchangeCodeForTokenAsync(UserId, authorizationCode.Code, returnUrl,
taskCancellationToken).ConfigureAwait(false);
// Extract the right state.
var oauthState = await AuthWebUtility.ExtracRedirectFromState(Flow.DataStore, UserId,
authorizationCode.State).ConfigureAwait(false);
return new RedirectResult(oauthState);
}
protected override Google.Apis.Auth.OAuth2.Mvc.FlowMetadata FlowData
{
get { return new AppFlowMetadata(); }
}
protected override ActionResult OnTokenError(TokenErrorResponse errorResponse)
{
throw new TokenResponseException(errorResponse);
}
//public class AuthCallbackController : Google.Apis.Auth.OAuth2.Mvc.Controllers.AuthCallbackController
//{
// protected override Google.Apis.Auth.OAuth2.Mvc.FlowMetadata FlowData
// {
// get { return new AppFlowMetadata(); }
// }
//}
}
Method for Controller calling Google API
public async Task<ActionResult> GoogleCalendarAsync(CancellationToken cancellationToken)
{
var result = await new AuthorizationCodeMvcApp(this, new AppFlowMetadata()).
AuthorizeAsync(cancellationToken);
if (result.Credential != null)
{
//var ttt = await result.Credential.RevokeTokenAsync(cancellationToken);
//bool x = await result.Credential.RefreshTokenAsync(cancellationToken);
var service = new CalendarService(new BaseClientService.Initializer()
{
HttpClientInitializer = result.Credential,
ApplicationName = "GoogleApplication",
});
var t = service.Calendars;
var tt = service.CalendarList.List();
// Define parameters of request.
EventsResource.ListRequest request = service.Events.List("primary");
request.TimeMin = DateTime.Now;
request.ShowDeleted = false;
request.SingleEvents = true;
request.MaxResults = 10;
request.OrderBy = EventsResource.ListRequest.OrderByEnum.StartTime;
// List events.
Events events = request.Execute();
Debug.WriteLine("Upcoming events:");
if (events.Items != null && events.Items.Count > 0)
{
foreach (var eventItem in events.Items)
{
string when = eventItem.Start.DateTime.ToString();
if (String.IsNullOrEmpty(when))
{
when = eventItem.Start.Date;
}
Debug.WriteLine("{0} ({1})", eventItem.Summary, when);
}
}
else
{
Debug.WriteLine("No upcoming events found.");
}
//Event myEvent = new Event
//{
// Summary = "Appointment",
// Location = "Somewhere",
// Start = new EventDateTime()
// {
// DateTime = new DateTime(2014, 6, 2, 10, 0, 0),
// TimeZone = "America/Los_Angeles"
// },
// End = new EventDateTime()
// {
// DateTime = new DateTime(2014, 6, 2, 10, 30, 0),
// TimeZone = "America/Los_Angeles"
// },
// Recurrence = new String[] {
// "RRULE:FREQ=WEEKLY;BYDAY=MO"
// },
// Attendees = new List<EventAttendee>()
// {
// new EventAttendee() { Email = "[email protected]" }
// }
//};
//Event recurringEvent = service.Events.Insert(myEvent, "primary").Execute();
return View();
}
else
{
return new RedirectResult(result.RedirectUri);
}
}
Derived class of FlowMetadata
public class AppFlowMetadata : FlowMetadata
{
//static readonly string server = ConfigurationManager.AppSettings["DatabaseServer"];
//static readonly string serverUser = ConfigurationManager.AppSettings["DatabaseUser"];
//static readonly string serverPassword = ConfigurationManager.AppSettings["DatabaseUserPassword"];
//static readonly string serverDatabase = ConfigurationManager.AppSettings["DatabaseName"];
////new FileDataStore("Daimto.GoogleCalendar.Auth.Store")
////new FileDataStore("Drive.Api.Auth.Store")
//static DatabaseDataStore databaseDataStore = new DatabaseDataStore(server, serverUser, serverPassword, serverDatabase);
private static readonly IAuthorizationCodeFlow flow =
new ForceOfflineGoogleAuthorizationCodeFlow(new GoogleAuthorizationCodeFlow.Initializer
{
ClientSecrets = new ClientSecrets
{
ClientId = "yourClientId",
ClientSecret = "yourClientSecret"
},
Scopes = new[]
{
CalendarService.Scope.Calendar, // Manage your calendars
//CalendarService.Scope.CalendarReadonly // View your Calendars
},
DataStore = new EFDataStore(),
});
public override string GetUserId(Controller controller)
{
// In this sample we use the session to store the user identifiers.
// That's not the best practice, because you should have a logic to identify
// a user. You might want to use "OpenID Connect".
// You can read more about the protocol in the following link:
// https://developers.google.com/accounts/docs/OAuth2Login.
//var user = controller.Session["user"];
//if (user == null)
//{
// user = Guid.NewGuid();
// controller.Session["user"] = user;
//}
//return user.ToString();
//var store = new UserStore<ApplicationUser>(new ApplicationDbContext());
//var manager = new UserManager<ApplicationUser>(store);
//var currentUser = manager.FindById(controller.User.Identity.GetUserId());
return controller.User.Identity.GetUserId();
}
public override IAuthorizationCodeFlow Flow
{
get { return flow; }
}
public override string AuthCallback
{
get { return @"/GoogleApplication/AuthCallback/IndexAsync"; }
}
}
Entity framework 6 DataStore class
public class EFDataStore : IDataStore
{
public async Task ClearAsync()
{
using (var context = new ApplicationDbContext())
{
var objectContext = ((IObjectContextAdapter)context).ObjectContext;
await objectContext.ExecuteStoreCommandAsync("TRUNCATE TABLE [Items]");
}
}
public async Task DeleteAsync<T>(string key)
{
if (string.IsNullOrEmpty(key))
{
throw new ArgumentException("Key MUST have a value");
}
using (var context = new ApplicationDbContext())
{
var generatedKey = GenerateStoredKey(key, typeof(T));
var item = context.GoogleAuthItems.FirstOrDefault(x => x.Key == generatedKey);
if (item != null)
{
context.GoogleAuthItems.Remove(item);
await context.SaveChangesAsync();
}
}
}
public Task<T> GetAsync<T>(string key)
{
if (string.IsNullOrEmpty(key))
{
throw new ArgumentException("Key MUST have a value");
}
using (var context = new ApplicationDbContext())
{
var generatedKey = GenerateStoredKey(key, typeof(T));
var item = context.GoogleAuthItems.FirstOrDefault(x => x.Key == generatedKey);
T value = item == null ? default(T) : JsonConvert.DeserializeObject<T>(item.Value);
return Task.FromResult<T>(value);
}
}
public async Task StoreAsync<T>(string key, T value)
{
if (string.IsNullOrEmpty(key))
{
throw new ArgumentException("Key MUST have a value");
}
using (var context = new ApplicationDbContext())
{
var generatedKey = GenerateStoredKey(key, typeof(T));
string json = JsonConvert.SerializeObject(value);
var item = await context.GoogleAuthItems.SingleOrDefaultAsync(x => x.Key == generatedKey);
if (item == null)
{
context.GoogleAuthItems.Add(new GoogleAuthItem { Key = generatedKey, Value = json });
}
else
{
item.Value = json;
}
await context.SaveChangesAsync();
}
}
private static string GenerateStoredKey(string key, Type t)
{
return string.Format("{0}-{1}", t.FullName, key);
}
}
Derived class for GoogleAuthorizationCodeFlow. Enabling long-lived refresh token that take care of automatically “refreshing” the token, which simply means getting a new access token.
https://developers.google.com/api-client-library/dotnet/guide/aaa_oauth
internal class ForceOfflineGoogleAuthorizationCodeFlow : GoogleAuthorizationCodeFlow
{
public ForceOfflineGoogleAuthorizationCodeFlow(GoogleAuthorizationCodeFlow.Initializer initializer) : base (initializer) { }
public override AuthorizationCodeRequestUrl CreateAuthorizationCodeRequest(string redirectUri)
{
return new GoogleAuthorizationCodeRequestUrl(new Uri(AuthorizationServerUrl))
{
ClientId = ClientSecrets.ClientId,
Scope = string.Join(" ", Scopes),
RedirectUri = redirectUri,
AccessType = "offline",
ApprovalPrompt = "force"
};
}
}
GoogleAuthItem is used with EFDataStore
public class GoogleAuthItem
{
[Key]
[MaxLength(100)]
public string Key { get; set; }
[MaxLength(500)]
public string Value { get; set; }
}
public DbSet<GoogleAuthItem> GoogleAuthItems { get; set; }