为什么我无法从谷歌的OAuth请求接收RefreshToken？ [英] Why am I not receiving a RefreshToken from a Google OAuth request?

问题描述

我试图谷歌日历集成到我的应用程序，我有一些问题OAuth授权假冒一个RefreshToken。我收到的accessToken没有问题，但RefreshToken属性为null。请参见标行错误的位置：对于那些我遇到的问题

I am attempting to integrate Google Calendar into my application and I am having some problems with the OAuth authorization passing off a RefreshToken. I receive an AccessToken with no issue, but the RefreshToken property is null. See the line marked "ERROR HERE:" for where I am having the issue

我的Asp.Net MVC控制器（名为 OAuthController ），如下所示：

My Asp.Net MVC controller (named OAuthController) looks like the following:

    public ActionResult Index()
    {
        var client = CreateClient();
        client.RequestUserAuthorization(new[] { "https://www.googleapis.com/auth/calendar" }, new Uri("http://localhost/FL.Evaluation.Web/OAuth/CallBack"));

        return View();
    }

    public ActionResult CallBack()
    {

        if (string.IsNullOrEmpty(Request.QueryString["code"])) return null;

        var client = CreateClient();

        // Now getting a 400 Bad Request here
        var state = client.ProcessUserAuthorization();

        // ERROR HERE:  The RefreshToken is NULL
        HttpContext.Session["REFRESH_TOKEN"] = Convert.ToBase64String(Encoding.Unicode.GetBytes(state.RefreshToken));

        return JavaScript("Completed!");
    }

    private static WebServerClient CreateClient()
    {
        return
            new WebServerClient(
                new AuthorizationServerDescription()
                    {
                        TokenEndpoint = new Uri("https://accounts.google.com/o/oauth2/token"),
                        AuthorizationEndpoint = new Uri("https://accounts.google.com/o/oauth2/auth"),
                        ProtocolVersion = ProtocolVersion.V20
                    }
                , _GoogleClientId, _GoogleSecret);
    }

我看到了谷歌的API文档，我需要确保 ACCESS_TYPE 请设置为离线的要发送一个RefreshToken。我如何设置我的身份验证请求，这个值？

I see in Google's API documents, that I need to ensure that the access_type requested is set to offline for a RefreshToken to be sent. How do I set this value in my Authenticator request?

推荐答案

在与 DotNetOpenAuth 和的谷歌API的的发表对于.NET，我无处快。我决定绕过图书馆去直接与当地的谷歌REST API 的Htt prequest和$的Htt p $ psponse对象。我的消毒code为我的MVC控制器如下：

After hours of fiddling with DotNetOpenAuth and the Google APIs published for .Net, I got nowhere fast. I decided to circumvent the libraries and went directly at the Google REST API with native HttpRequest and HttpResponse objects. My sanitized code for my MVC controller follows:

    private static string _GoogleClientId = "CLIENT_ID";
    private static string _GoogleSecret = "SECRET";
    private static string _ReturnUrl = "http://localhost/OAuth/CallBack";

    public ActionResult Index()
    {
        return Redirect(GenerateGoogleOAuthUrl());
    }

    private string GenerateGoogleOAuthUrl()
    {

        //NOTE: Key piece here, from Andrew's reply -> access_type=offline forces a refresh token to be issued
        string Url = "https://accounts.google.com/o/oauth2/auth?scope={0}&redirect_uri={1}&response_type={2}&client_id={3}&state={4}&access_type=offline&approval_prompt=force";
        string scope = UrlEncodeForGoogle("https://www.googleapis.com/auth/calendar https://www.googleapis.com/auth/calendar.readonly").Replace("%20", "+");
        string redirect_uri_encode = UrlEncodeForGoogle(_ReturnUrl);
        string response_type = "code";
        string state = "";

        return string.Format(Url, scope, redirect_uri_encode, response_type, _GoogleClientId, state);

    }

    private static string UrlEncodeForGoogle(string url)
    {
        string UnReservedChars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789-_.~";
        var result = new StringBuilder();

        foreach (char symbol in url)
        {
            if (UnReservedChars.IndexOf(symbol) != -1)
            {
                result.Append(symbol);
            }
            else
            {
                result.Append('%' + String.Format("{0:X2}", (int)symbol));
            }
        }

        return result.ToString();
    }

    class GoogleTokenData
    {
        public string Access_Token { get; set; }
        public string Refresh_Token { get; set; }
        public string Expires_In { get; set; }
        public string Token_Type { get; set; }
    }

    public ActionResult CallBack(string code, bool? remove)
    {

        if (remove.HasValue && remove.Value)
        {
            Session["GoogleAPIToken"] = null;
            return HttpNotFound();
        }

        if (string.IsNullOrEmpty(code)) return Content("Missing code");

        string Url = "https://accounts.google.com/o/oauth2/token";
        string grant_type = "authorization_code";
        string redirect_uri_encode = UrlEncodeForGoogle(_ReturnUrl);
        string data = "code={0}&client_id={1}&client_secret={2}&redirect_uri={3}&grant_type={4}";

        HttpWebRequest request = HttpWebRequest.Create(Url) as HttpWebRequest;
        string result = null;
        request.Method = "POST";
        request.KeepAlive = true;
        request.ContentType = "application/x-www-form-urlencoded";
        string param = string.Format(data, code, _GoogleClientId, _GoogleSecret, redirect_uri_encode, grant_type);
        var bs = Encoding.UTF8.GetBytes(param);
        using (Stream reqStream = request.GetRequestStream())
        {
            reqStream.Write(bs, 0, bs.Length);
        }

        using (WebResponse response = request.GetResponse())
        {
            var sr = new StreamReader(response.GetResponseStream());
            result = sr.ReadToEnd();
            sr.Close();
        }

        var jsonSerializer = new JavaScriptSerializer();
        var tokenData = jsonSerializer.Deserialize<GoogleTokenData>(result);
        Session["GoogleAPIToken"] = tokenData.Access_Token;

        return JavaScript("Refresh Token: " + tokenData.Refresh_Token);

    }

非常感谢海带了一下的code在这个片段。

Big thanks to Kelp for a bit of the code in this snippet.

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