关于PayPal第三方登录的接口问题

按照官网上面的方法试了几次都会出现各种问题，于是稍作改动：

　　首先，找到官网的SDK，注意版本，可能会出现NewTonSoft.Json版本不对的问题。

        public ActionResult Button() 
        {
            string redirectURI = "https://www.sandbox.paypal.com/webapps/auth/protocol/openidconnect/v1/authorize?client_id= aaa &response_type=code&scope=openid email&redirect_uri=http://xxx";
            return Redirect(redirectURI);
        }

　　将aaa换成自己的client_id,xxx换成自己需要返回的方法，不需要加返回值；

        public void Receive(String code)
        {
            //填写自己的Client_ID
            var oAuthClientId = "aaa";
            //对应的Client_Secret
            var oAuthClientSecret = "bbb";
            var oAuthUrl = "https://api.sandbox.paypal.com/v1/identity/openidconnect/tokenservice";

            var authHeader = string.Format("Basic {0}",
                                           Convert.ToBase64String(
                                               Encoding.UTF8.GetBytes(Uri.EscapeDataString(oAuthClientId) + ":" +
                                                                      Uri.EscapeDataString((oAuthClientSecret)))
                                               ));

            //passing code here
            var postBody = string.Format("grant_type=authorization_code&code={0}", code);
var authRequest = (HttpWebRequest)WebRequest.Create(oAuthUrl);
            authRequest.Headers.Add("Authorization", authHeader);
            authRequest.Method = "POST";
            byte[] postcontentsArray = Encoding.UTF8.GetBytes(postBody);
            authRequest.ContentType = "application/x-www-form-urlencoded;charset=UTF-8";
            authRequest.ContentLength = postcontentsArray.Length;

            try
            {
                using (Stream stream = authRequest.GetRequestStream())
                {
                    stream.Write(postcontentsArray, 0, postcontentsArray.Length);
                    stream.Close();

                    WebResponse response = authRequest.GetResponse();
                    using (Stream responseStream = response.GetResponseStream())
                        if (responseStream != null)
                        {
                            using (var reader = new StreamReader(responseStream))
                            {
                                string responseFromServer = reader.ReadToEnd();
                                reader.Close();
                                responseStream.Close();
                                response.Close();
                                //this will return you access token which you can use to get user information
                                //使用JsonSerializer读写对象(基于JsonWriter与JsonReader)
                                var responseResult =
                                    (JObject)JsonConvert.DeserializeObject(responseFromServer);
                                //var a1 = responseResult["access_token"].ToString();
                                Dictionary<string, string> configurationMap = new Dictionary<string, string>();
                                configurationMap.Add("mode", "sandbox");

                                APIContext apiContext = new APIContext();
                                apiContext.Config = configurationMap;

                                UserinfoParameters userinfoParams = new UserinfoParameters();
                                //传入参数access_token
                                userinfoParams.SetAccessToken(responseResult["access_token"].ToString());
                                //得到用户信息
                                Userinfo userinfo = Userinfo.GetUserinfo(apiContext, userinfoParams);
                            }
                        }
                }
            }
            catch (Exception e)
            {
                //log error
            }
        }

    此时可能会出现：“请求被中止：未能创建SSL/TLS安全通道"的问题，在new HttpWebRequest之前加入以下代码可以解决此问题。
　　 System.Net.ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
　　默认状态下，得到的用户信息包含email和一个用户ID