我花了最近两天的时间自己研究这个问题。除非您指定 "access_type=offline"，否则该库不会自动刷新令牌。
https://developers.google.com/api-client-library/dotnet/guide/aaa_oauth
我将贴出我正在使用的代码，如果有什么不明白的，请问一下。我已经阅读了很多帖子，现在它确实可以工作了，所以有一些注释的代码，还没有重构。我希望这能帮助到某些人。我正在使用的NuGet包是这些：
Google.Apis.Auth.MVC
Google.Apis.Calendar.v3
代码：
认证回调控制器：
[AuthorizationCodeActionFilter]
public class AuthCallbackController : Google.Apis.Auth.OAuth2.Mvc.Controllers.AuthCallbackController
{
protected static readonly ILogger Logger = ApplicationContext.Logger.ForType<AuthCallbackController>();
protected IAuthorizationCodeFlow Flow { get { return FlowData.Flow; } }
protected string UserId { get { return FlowData.GetUserId(this); } }
[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);
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);
}
}
控制器调用Google API的方法
public async Task<ActionResult> GoogleCalendarAsync(CancellationToken cancellationToken)
{
var result = await new AuthorizationCodeMvcApp(this, new AppFlowMetadata()).
AuthorizeAsync(cancellationToken);
if (result.Credential != null)
{
var service = new CalendarService(new BaseClientService.Initializer()
{
HttpClientInitializer = result.Credential,
ApplicationName = "GoogleApplication",
});
var t = service.Calendars;
var tt = service.CalendarList.List();
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;
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.");
}
return View();
}
else
{
return new RedirectResult(result.RedirectUri);
}
}
FlowMetadata的派生类
public class AppFlowMetadata : FlowMetadata
{
private static readonly IAuthorizationCodeFlow flow =
new ForceOfflineGoogleAuthorizationCodeFlow(new GoogleAuthorizationCodeFlow.Initializer
{
ClientSecrets = new ClientSecrets
{
ClientId = "yourClientId",
ClientSecret = "yourClientSecret"
},
Scopes = new[]
{
CalendarService.Scope.Calendar,
},
DataStore = new EFDataStore(),
});
public override string GetUserId(Controller controller)
{
return controller.User.Identity.GetUserId();
}
public override IAuthorizationCodeFlow Flow
{
get { return flow; }
}
public override string AuthCallback
{
get { return @"/GoogleApplication/AuthCallback/IndexAsync"; }
}
}
实体框架 6 数据存储类
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);
}
}
继承自GoogleAuthorizationCodeFlow的派生类。启用长期有效的刷新令牌，自动"刷新"令牌，即获取新的访问令牌。请保留HTML标签。
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与EFDataStore一起使用
public class GoogleAuthItem
{
[Key]
[MaxLength(100)]
public string Key { get; set; }
[MaxLength(500)]
public string Value { get; set; }
}
public DbSet<GoogleAuthItem> GoogleAuthItems { get; set; }
