asp.net core 微信获取用户openid

　　获取openid流程为首先根据微信开发参数构造AuthorizeUrl认证链接，用户跳转到该链接进行授权，授权完成将跳转到回调页（首次认证需要授权，后面将直接再跳转至回调页），此时回调页中带上一个GET参数code，使用该code请求微信接口得到用户的openid。话不多说，直接上代码。

1.编写认证类OAuth

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public class OAuth     {         public static HttpClient httpClient = new HttpClient();         public static string GetAuthorizeUrl(string appId, string redirectUrl, string state= "state", string scope = "snsapi_base", string responseType = "code")         {             if (!string.IsNullOrEmpty(redirectUrl))             {                 redirectUrl = HttpUtility.UrlEncode(redirectUrl, System.Text.Encoding.UTF8);             }             else             {                 redirectUrl = null;             }             object[] args = new object[] { appId, redirectUrl, responseType, scope, state };             return string.Format("https://open.weixin.qq.com/connect/oauth2/authorize?appid={0}&redirect_uri={1}&response_type={2}&scope={3}&state={4}#wechat_redirect", args);         }           public static string GetOpenIdUrl(string appId, string secret, string code, string grantType = "authorization_code")         {             object[] args = new object[] { appId, secret, code, grantType };             string requestUri = string.Format("https://api.weixin.qq.com/sns/oauth2/access_token?appid={0}&secret={1}&code={2}&grant_type={3}", args);             return requestUri;         }           /// <summary>         /// 获取openid         /// </summary>         /// <param name="appId"></param>         /// <param name="secret"></param>         /// <param name="code"></param>         /// <param name="grantType"></param>         /// <returns></returns>         public static string GetOpenid(string appId, string secret, string code, string grantType = "authorization_code")         {             string requestUri = GetOpenIdUrl(appId, secret, code, grantType);             var responseStr = httpClient.GetAsync(requestUri).Result.Content.ReadAsStringAsync().Result;             var obj = JsonConvert.DeserializeObject<Dictionary<string, string>>(responseStr);             string openid = string.Empty;             if (!obj.TryGetValue("openid", out openid))             {                 Log.Info($"获取openid失败appId={appId}，secret={secret}，code={code}");             }             return openid;         }     }

　　2.在控制器中使用认证类获取用户openid,注意：访问该控制器地址确保微信回调时候也能访问到该地址

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/// <summary>        /// 获取微信openid        /// </summary>        /// <param name="code"></param>        /// <returns></returns>        [HttpGet]         public IActionResult GetWxOpenid(string code)         {             WxPayConfig wxPayConfig = new WxPayConfig();             //首先构造微信请求授权url，重定向到该url中，其中redirectUrl是回调地址，必须保证该地址在公网上能访问，本例子构造的是返回到本控制器的方法。             //若是从微信授权返回进入该方法，则会带上一个参数，code就不为空，若code为空则跳转微信授权             if (string.IsNullOrEmpty(code))             {                 var redirectUrl = OAuth.GetAuthorizeUrl(wxPayConfig.appid, "回调地址到公网本Action");                 return Redirect(redirectUrl);             }             else             {                 //根据code和微信参数得到openid                 var openId = OAuth.GetOpenid(wxPayConfig.appid, wxPayConfig.appSecret, code);                 //业务处理                               }             return View();         }

　　通过使用OAuth类轻松的就能获取用户的Openid

附上写日志的一个老师傅写类库Sky.Logger，在项目中添加引用即可使用日志：链接: https://pan.baidu.com/s/1eHdNGZN0pmNHsO_yHzgE_g 密码: ta2x