如何使用服务帐户对Google v3 api进行身份验证

Question

下面是示例代码:https://code.google.com/p/google-api-dotnet-client/wiki/oauth2#service_accounts

授权失败：dotnetOpenAuth.Messaging.ProtocolException：发送直接消息或获取响应时出错。

内部异常是System.net.WebException：远程服务器返回错误：（400）Bad Request。响应正文为空，响应URI为https://accounts.google.com/o/oauth2/token。

在下面的响应中，您将看到特定的错误是invalid_grant。

var certificate = new X509Certificate2(CertificatePath, "notasecret", X509KeyStorageFlags.Exportable);
var provider = new AssertionFlowClient(GoogleAuthenticationServer.Description, certificate)
    {
        ServiceAccountId = "<...>@developer.gserviceaccount.com",
        Scope = CalendarService.Scopes.Calendar.GetStringValue()
    };

var authenticator = new OAuth2Authenticator<AssertionFlowClient>(provider, AssertionFlowClient.GetState);

var calendarService =
    new CalendarService(new BaseClientService.Initializer()
        {
            Authenticator = authenticator
        });

var eventList = calendarService.Events.List("<id of the calendar>").Execute();

null

null

POST https://accounts.google.com/o/oauth2/token HTTP/1.1
Content-Type: application/x-www-form-urlencoded; charset=utf-8
User-Agent: DotNetOpenAuth/4.0.0.11165
Host: accounts.google.com
Cache-Control: no-store,no-cache
Pragma: no-cache
Content-Length: 606
Connection: Keep-Alive

grant_type=assertion&assertion_type=http%3A%2F%2Foauth.net%2Fgrant_type%2Fjwt%2F1.0%2Fbearer&assertion=eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiI5NzUzOTk3NzMyNi01NHFvMXY4OW5iZTk4dGNlbGIycWY0cDdjNThzYjhmMkBkZXZlbG9wZXIuZ3NlcnZpY2VhY2NvdW50LmNvbSIsInNjb3BlIjoiaHR0cHM6Ly93d3cuZ29vZ2xlYXBpcy5jb20vYXV0aC9jYWxlbmRhciIsImF1ZCI6Imh0dHBzOi8vYWNjb3VudHMuZ29vZ2xlLmNvbS9vL29hdXRoMi90b2tlbiIsImV4cCI6MTM3OTU5MTA4MywiaWF0IjoxMzc5NTg3NDgzfQ.Ls_sv40MfB8MAD92JFcFiW5YYoRytQ3e2PA8RV_hn4FJfVHDo6uCSunN7950H2boO6LfX9EMrpjaf8ZyNyHyrQucQaWwfIFD6F2FpnqlcNkzXoqWMCwkt-k-8ypGMSZfFCEkhw8QOrlIPFZb6qx61689n08G9tZMTzHGYc2b8Gk

{"alg":"RS256","typ":"JWT"}{"iss":"[e-mail]","scope":"https://www.googleapis.com/auth/calendar","aud":"https://accounts.google.com/o/oauth2/token","exp":1379591083,"iat":1379587483}

HTTP/1.1 400 Bad Request
Cache-Control: no-cache, no-store, max-age=0, must-revalidate
Pragma: no-cache
Expires: Fri, 01 Jan 1990 00:00:00 GMT
Date: Thu, 19 Sep 2013 10:44:42 GMT
Content-Type: application/json
X-Content-Type-Options: nosniff
X-Frame-Options: SAMEORIGIN
X-XSS-Protection: 1; mode=block
Server: GSE
Alternate-Protocol: 443:quic
Content-Length: 31

{
  "error" : "invalid_grant"
}

为了确认设置正确，我使用google-oauth-jwt手动创建了一个令牌（这里是：https://github.com/extrabacon/google-oauth-jwt）。我能够使用与上面代码相同的属性成功地创建一个令牌。一旦我创建了令牌并在自定义IAuthenticator中使用它，我就可以成功地从目标Google Apps域中的用户日历中检索事件。因此，如果您想知道，日历访问是可能的服务帐户！

下面是IAuthenticator实现，它只需添加授权标头：

public class Authenticator : IAuthenticator
{
  public void ApplyAuthenticationToRequest(System.Net.HttpWebRequest request)
  {
    request.Headers.Add(HttpRequestHeader.Authorization, "Bearer <token here>");
  }
}

Answer 1

我不确定自从这个问题被问到之后是否有什么变化，但谷歌日历实际上支持服务帐户。

当设置一个服务帐户使用谷歌日历API时，您只需要采取服务帐户的电子邮件地址。去谷歌日历网站。找到日历设置，然后转到日历选项卡，找到要访问的日历，然后单击“共享：编辑设置”，添加服务帐户电子邮件地址，就像添加个人电子邮件地址一样。这将赋予服务帐户相同的访问权限，就像您在哪里与任何其他用户共享它一样。

string[] scopes = new string[] {
    CalendarService.Scope.Calendar, // Manage your calendars
    CalendarService.Scope.CalendarReadonly // View your Calendars
 };

 var certificate = new X509Certificate2(keyFilePath, "notasecret", X509KeyStorageFlags.Exportable);

ServiceAccountCredential credential = new ServiceAccountCredential(
    new ServiceAccountCredential.Initializer(serviceAccountEmail) {
        Scopes = scopes
    }.FromCertificate(certificate));

// Create the service.
    CalendarService service = new CalendarService(new BaseClientService.Initializer() {
        HttpClientInitializer = credential,
        ApplicationName = "Calendar API Sample",
    });

从Google Calendar API身份验证C#中提取的代码