我正在根据以下内容通过 Google+ 进行身份验证： https ://developers.google.com/+/mobile/android/sign-in
这个过程的大部分似乎都很好。我遇到的问题是我们需要获得一个“一次性授权码”，以便我们的后端服务器可以在用户许可的情况下代表用户执行某些请求。这在“为您的应用启用服务器端 api 访问”部分中进行了介绍。但是，由于多种原因，即使授权码有效，我们的服务器也可能导致登录失败（例如，用户在我们的服务器上还没有与 google+ 帐户对应的帐户，在这种情况下，他们可以一）。
如果发生这种情况，我们可能需要他们稍后再次登录。不过，我发现，当我使用 google+ 执行第二次登录时，它给了我相同的授权码，即使它已经被我们的服务器使用。我已经尝试断开并重新连接到谷歌客户端 api，然后调用GoogleApiClient.clearDefaultAccountAndReconnect()，但无论我做什么，我似乎最终都会得到相同的授权码。当然，当它尝试使用它时，它会被服务器拒绝，因为它已经被使用过。
我想知道我在这里做错了什么。我有以下方法，在初始认证过程中调用，然后如果500从我们的服务器检测到响应状态（表明之前的调用失败，可能是因为代码已经被使用）：
private void dispatchGooglePlusAuthCodeAcquisition() {
AsyncTask<Void, Void, String> authAcquisition = new AsyncTask<Void, Void, String>() {
@Override
protected String doInBackground(Void... params) {
Bundle authPreferences = new Bundle();
mUserPermissionNeededForAuthCode = false;
authPreferences.putString(GoogleAuthUtil.KEY_REQUEST_VISIBLE_ACTIVITIES,
"");
String scopesString = Scopes.PROFILE;
WhenIWorkApplication app = (WhenIWorkApplication)WhenIWorkApplication.getInstance();
String serverClientID = app.getGoogleOAuthClientIDForPersonalServer();
String scope = "oauth2:server:client_id:" + serverClientID + ":api_scope:" + scopesString;
String code = null;
authPreferences.putBoolean(GoogleAuthUtil.KEY_SUPPRESS_PROGRESS_SCREEN, true);
try {
code = GoogleAuthUtil.getToken(
mActivity,
Plus.AccountApi.getAccountName(mGoogleApiClient),
scope,
authPreferences
);
} catch (IOException transientEx) {
// network or server error, the call is expected to succeed if you try again later.
// Don't attempt to call again immediately - the request is likely to
// fail, you'll hit quotas or back-off.
Log.d(LOGTAG, "Encountered an IOException while trying to login to Google+."
+ " We'll need to try again at a later time.");
} catch (UserRecoverableAuthException e) {
mUserPermissionNeededForAuthCode = true;
// Requesting an authorization code will always throw
// UserRecoverableAuthException on the first call to GoogleAuthUtil.getToken
// because the user must consent to offline access to their data. After
// consent is granted control is returned to your activity in onActivityResult
// and the second call to GoogleAuthUtil.getToken will succeed.
if (!mGooglePlusPermissionActivityStarted) {
mGooglePlusPermissionActivityStarted = true;
mActivity.startActivityForResult(e.getIntent(), RESULT_CODE_AUTH_CODE);
}
} catch (GoogleAuthException authEx) {
// Failure. The call is not expected to ever succeed so it should not be
// retried.
Log.e(LOGTAG, "Unable to authenticate to Google+. Call will likely never"
+ " succeed, so bailing.", authEx);
}
return code;
}
@Override
protected void onPostExecute(String aResult) {
if (aResult != null) {
// We retrieved an authorization code successfully.
if (mAPIAccessListener != null) {
mAPIAccessListener.onAuthorizationCodeGranted(aResult);
}
} else if (!mUserPermissionNeededForAuthCode) {
// If this is the case, then we didn't get authorization from the user, or something
// else happened.
if (mAPIAccessListener != null) {
mAPIAccessListener.onAuthorizationFailed();
}
Log.d(LOGTAG, "Unable to login because authorization code retrieved was null");
}
}
};
authAcquisition.execute();