.Net之微信小程序获取用户UnionID的实现

// 用户已经授权
wx.getUserInfo({
success: function(res) {
console.log(res);
var userInfo = res.userInfo //用户基本信息
let sessionKey = wx.getStorageSync("session_key");//临时会话密钥，通过小程序登录流程获取到的
//请求.net webapi解密接口
wx.request({
 url: 'https://www.xxxtest.com/api/User_oAuth/DecryptSensitiveData',
data: {
sessionKey:sessionKey,
encryptedData:res.encryptedData,
iv:res.iv
},
 header: {
'content-type': 'application/json' // 默认值
},
success (res) {
//解密返回过来的UnionID
console.log(res.data)
}
})
}
})
})

/// <summary>
  /// 解密微信对称加密数据，获取用户联合运营编号
  /// </summary>
  /// <param name="sessionKey">临时会话秘钥</param>
  /// <param name="encryptedData">微信用户敏感加密数据</param>
  /// <param name="iv">解密初始向量</param>
  /// <returns></returns>
  [HttpGet]
  public IHttpActionResult DecryptSensitiveData(string sessionKey,string encryptedData,string iv)
  {
   try
   {
    var getUnionId=DecryptByAesBytes(encryptedData, sessionKey, iv);

    return Json(new { code =1, msg="解密成功",result= getUnionId });
   }
   catch (Exception ex)
   {
    return Json(new { code = 0, msg = "解密失败,原因："+ex.Message });
   }
  }

  #region AES对称解密
  /// <summary>
  /// AES解密
  /// </summary>
  /// <param name="encryptedData">待解密的字节数组</param>
  /// <param name="sessionKey">解密密钥字节数组</param>
  /// <param name="iv">IV初始化向量字节数组</param>
  /// <param name="cipher">运算模式</param>
  /// <param name="padding">填充模式</param>
  /// <returns></returns>
  private static string DecryptByAesBytes(string encryptedData, string sessionKey, string iv)
  {
   try
   {
    //非空验证
    if (!string.IsNullOrWhiteSpace(encryptedData) && !string.IsNullOrWhiteSpace(sessionKey) && !string.IsNullOrWhiteSpace(iv))
    {
     var decryptBytes = Convert.FromBase64String(encryptedData.Replace(' ', '+'));
     var keyBytes = Convert.FromBase64String(sessionKey.Replace(' ', '+'));
     var ivBytes = Convert.FromBase64String(iv.Replace(' ', '+'));

     var aes = new AesCryptoServiceProvider
     {
      Key = keyBytes,
      IV = ivBytes,
      Mode = CipherMode.CBC,
      Padding = PaddingMode.PKCS7
     };

     var outputBytes = aes.CreateDecryptor().TransformFinalBlock(decryptBytes, 0, decryptBytes.Length);

     var decryptResult = Encoding.UTF8.GetString(outputBytes);
     dynamic decryptData = JsonConvert.DeserializeObject(decryptResult, new { unionid = "" }.GetType());
     JJHL.Utility.Loghelper.WriteLog("AES对称解密结果为：" + decryptResult);
     return decryptData.unionid;
    }
    else
    {
     return "";
    }
   }
   catch (Exception e)
   {
    JJHL.Utility.Loghelper.WriteLog("AES对称解密失败原因：" + e.Message);
    return "";
   }
  }

  #endregion

 代码如下:
/***封装用户promise登录，通过code凭证获取用户信息（UnionID,openid,session_key会话密钥）*/userLogin: function() {var that = this;//定义promise方法return new Promise(function(resolve, reject) {//调用登录接口wx.login({success: function(res) {if (res.code) {console.log("用户登录授权code为：" + res.code);//调用wx.request请求传递code凭证换取用户openid，并获取后台用户信息wx.request({url: 'https://www.xxxx.xxx.api/User_oAuth/GetUserInfo',//后台请求用户信息方法data: {code: res.code //code凭证},header: {'content-type':'application/json' // 默认值},success(res) {console.log(res.data)if (res.data.errcode == 0) {//存入session缓存中console.log(res.data.openid);//微信用户唯一标识console.log(res.data.UnionID);//微信开发平台联合IDconsole.log(res.data.session_key);//会话密钥
//***注意****
//注意：这里是直接把session_key缓存起来，在上面wx.getUserInfo会使用到
wx.setStorageSync("session_key",res.data.session_key);
[code]//promise机制放回成功数据 
resolve(res.data); 
} else 
{ reject('error'); } 
}, fail: function(res) 
{ 
reject(res); 
wx.showToast({ title: '系统错误' }) 
}, complete: () => { } //complete接口执行后的回调函数，无论成功失败都会调用 
}) } else 
{ 
reject("error"); 
}}
})})}[/code

/// <summary>
  /// 获取用户信息
  /// </summary>
  /// <param name="code">信息数据code凭证</param>
  /// <returns></returns>
  [HttpGet]
  public IHttpActionResult GetUserInfo(string code)
  {
   string AppSecret = "小程序秘钥";
   string AppId = "应用程序标识";

   try
   {
    //请求目标地址和参数（authorization_code授权类型，此处只需填写 authorization_code）
    string OauthUrl = "https://api.weixin.qq.com/sns/jscode2session?appid=" + AppId + "&secret=" + AppSecret + "&js_code=" + code + "&grant_type=authorization_code";//序列化解析数据
    var Result = HttpGet(OauthUrl);

    return Json(new { openid = Result.openid, errcode = Result.errcode, UnionID = Result.unionid, session_key = Result.session_key });
   }
   catch (Exception ex)
   {

    return Json(new { errcode = 1, msg = "获取用户信息失败" + ex.Message });
   }
  }

  /// <summary>
  /// 请求code2Session接口获取用户信息
  /// </summary>
  /// <param name="requestDataAndUrl">目标地址和参数</param>
  /// <returns></returns>
  public WxOauthModle HttpGet(string requestDataAndUrl)
  {
   HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestDataAndUrl);
   request.Method = "GET";
   request.ContentType = "text/html;charset=UTF-8";
   HttpWebResponse response = (HttpWebResponse)request.GetResponse();
   Stream myResponseStream = response.GetResponseStream();
   StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.UTF8);
   string retString = myStreamReader.ReadToEnd();
   myStreamReader.Close();
   myResponseStream.Close();

   return JsonConvert.DeserializeObject<WxOauthModle>(retString);
  }

  public class WxOauthModle
  {
   /// <summary>
   /// 用户唯一标识
   /// </summary>
   public string openid { get; set; }

   /// <summary>
   /// 会话秘钥
   /// </summary>
   public string session_key { get; set; }

   /// <summary>
   /// 联立编号
   /// </summary>
   public string unionid { get; set; }

   /// <summary>
   /// 错误码
   /// </summary>
   public int errcode { get; set; }

   /// <summary>
   /// 错误信息
   /// </summary>
   public string errmsg { get; set; }
  }