更新：正如马特约翰逊在下面提到的那样，他已经打包了一个解决方案，您可以从 GitHub 获得该解决方案：https://github.com/mj1856/DotNetOpenAuth.GoogleOAuth2
正如他所说：
用于 ASP.Net MVC 4 的 DNOA 和 OAuthWebSecurity 仅附带 Google 的 OpenId 提供程序。这是您可以使用的 OAuth2 客户端。
重要 - 如果您使用的是 ASP.Net MVC 5，则此包不适用。您应该改用 Microsoft.Owin.Security.Google。 （它还附带 VS 2013 中的 MVC 5 入门模板。）
我最终解决了这个问题，方法是在请求进入时捕获它，并自己检查它来自哪个提供商。 Google 允许您向 OAuth 请求发送一个名为“state”的参数，当他们进行回调时，他们只是将其直接传回给您，所以我使用它来传递 google 的提供程序名称，并在没有"__provider__"。
类似这样的：
public String GetProviderNameFromQueryString(NameValueCollection queryString)
{
var result = queryString["__provider__"];
if (String.IsNullOrWhiteSpace(result))
{
result = queryString["state"];
}
return result;
}
然后我为 Google 实现了一个自定义 OAuth2Client，我自己手动调用了 VerifyAuthentication 方法，绕过了 Microsoft 包装器。
if (provider is GoogleCustomClient)
{
authenticationResult = ((GoogleCustomClient)provider).VerifyAuthentication(context, new Uri(String.Format("{0}/oauth/ExternalLoginCallback", context.Request.Url.GetLeftPart(UriPartial.Authority).ToString())));
}
else
{
authenticationResult = OAuthWebSecurity.VerifyAuthentication(returnUrl);
}
这使我可以使用 Microsoft 包装器为其他提供商保留我已经拥有的东西。
根据@1010100 1001010 的要求，这是我为 Google 定制的 OAuth2Client（注意：它需要一些整理！我还没有准备好整理代码。它确实有效）：
public class GoogleCustomClient : OAuth2Client
{
ILogger _logger;
#region Constants and Fields
/// <summary>
/// The authorization endpoint.
/// </summary>
private const string AuthorizationEndpoint = "https://accounts.google.com/o/oauth2/auth";
/// <summary>
/// The token endpoint.
/// </summary>
private const string TokenEndpoint = "https://accounts.google.com/o/oauth2/token";
/// <summary>
/// The _app id.
/// </summary>
private readonly string _clientId;
/// <summary>
/// The _app secret.
/// </summary>
private readonly string _clientSecret;
#endregion
public GoogleCustomClient(string clientId, string clientSecret)
: base("Google")
{
if (string.IsNullOrWhiteSpace(clientId)) throw new ArgumentNullException("clientId");
if (string.IsNullOrWhiteSpace(clientSecret)) throw new ArgumentNullException("clientSecret");
_logger = ObjectFactory.GetInstance<ILogger>();
this._clientId = clientId;
this._clientSecret = clientSecret;
}
protected override Uri GetServiceLoginUrl(Uri returnUrl)
{
StringBuilder serviceUrl = new StringBuilder();
serviceUrl.AppendFormat("{0}?scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.email+https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fuserinfo.profile", AuthorizationEndpoint);
serviceUrl.Append("&state=google");
serviceUrl.AppendFormat("&redirect_uri={0}", returnUrl.ToString());
serviceUrl.Append("&response_type=code");
serviceUrl.AppendFormat("&client_id={0}", _clientId);
return new Uri(serviceUrl.ToString());
}
protected override IDictionary<string, string> GetUserData(string accessToken)
{
RestClient client = new RestClient("https://www.googleapis.com");
var request = new RestRequest(String.Format("/oauth2/v1/userinfo?access_token={0}", accessToken), Method.GET);
IDictionary<String, String> extraData = new Dictionary<String, String>();
var response = client.Execute(request);
if (null != response.ErrorException)
{
return null;
}
else
{
try
{
var json = JObject.Parse(response.Content);
string firstName = (string)json["given_name"];
string lastName = (string)json["family_name"];
string emailAddress = (string)json["email"];
string id = (string)json["id"];
extraData = new Dictionary<String, String>
{
{"accesstoken", accessToken},
{"name", String.Format("{0} {1}", firstName, lastName)},
{"firstname", firstName},
{"lastname", lastName},
{"email", emailAddress},
{"id", id}
};
}
catch(Exception ex)
{
_logger.Error("Error requesting OAuth user data from Google", ex);
return null;
}
return extraData;
}
}
protected override string QueryAccessToken(Uri returnUrl, string authorizationCode)
{
StringBuilder postData = new StringBuilder();
postData.AppendFormat("client_id={0}", this._clientId);
postData.AppendFormat("&redirect_uri={0}", HttpUtility.UrlEncode(returnUrl.ToString()));
postData.AppendFormat("&client_secret={0}", this._clientSecret);
postData.AppendFormat("&grant_type={0}", "authorization_code");
postData.AppendFormat("&code={0}", authorizationCode);
string response = "";
string accessToken = "";
var webRequest = (HttpWebRequest)WebRequest.Create(TokenEndpoint);
webRequest.Method = "POST";
webRequest.ContentType = "application/x-www-form-urlencoded";
try
{
using (Stream s = webRequest.GetRequestStream())
{
using (StreamWriter sw = new StreamWriter(s))
sw.Write(postData.ToString());
}
using (WebResponse webResponse = webRequest.GetResponse())
{
using (StreamReader reader = new StreamReader(webResponse.GetResponseStream()))
{
response = reader.ReadToEnd();
}
}
var json = JObject.Parse(response);
accessToken = (string)json["access_token"];
}
catch(Exception ex)
{
_logger.Error("Error requesting OAuth access token from Google", ex);
return null;
}
return accessToken;
}
public override AuthenticationResult VerifyAuthentication(HttpContextBase context, Uri returnPageUrl)
{
string code = context.Request.QueryString["code"];
if (string.IsNullOrEmpty(code))
{
return AuthenticationResult.Failed;
}
string accessToken = this.QueryAccessToken(returnPageUrl, code);
if (accessToken == null)
{
return AuthenticationResult.Failed;
}
IDictionary<string, string> userData = this.GetUserData(accessToken);
if (userData == null)
{
return AuthenticationResult.Failed;
}
string id = userData["id"];
string name;
// Some oAuth providers do not return value for the 'username' attribute.
// In that case, try the 'name' attribute. If it's still unavailable, fall back to 'id'
if (!userData.TryGetValue("username", out name) && !userData.TryGetValue("name", out name))
{
name = id;
}
// add the access token to the user data dictionary just in case page developers want to use it
userData["accesstoken"] = accessToken;
return new AuthenticationResult(
isSuccessful: true, provider: this.ProviderName, providerUserId: id, userName: name, extraData: userData);
}