微信第三方平台处理授权公众号的网页授权接口

写一OAuthController的MVC控制器，用来接收公众号的网页授权请求

public async Task<ActionResult> RedirectCallback(string state, string code = "", string appid = "", string clienturl = "")
        {
            if (code.Length == 0)
            {
                if (clienturl.IndexOf("?") != -1)
                    return Redirect(OAuthCallback + clienturl + "&errcode=-1&errmsg=" + HttpUtility.UrlEncode("用户禁止授权"));
                else
                    return Redirect(OAuthCallback + clienturl + "?errcode=-1&errmsg=" + HttpUtility.UrlEncode("用户禁止授权"));
            }

            var ticketValue = "";
            string path = AppDomain.CurrentDomain.SetupInformation.ApplicationBase + @"configsWeChat.ThirdpartyPlatform.ComponentVerifyTicket.xml";
            using (StreamReader sr = new StreamReader(path, Encoding.UTF8))
            {
                string txt = sr.ReadToEnd();
                string[] lines = txt.Split("
".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                if (lines.Length == 4)
                    ticketValue = lines[3];
            }
            var accessTokenValue = await Authentication.GetComponentAccessToken(AppId, AppSecret, ticketValue);
            var jsonStr = await Util.HttpGetAsync("https://api.weixin.qq.com/sns/oauth2/component/access_token?appid=" + appid + "&code=" + code + "&grant_type=authorization_code&component_appid=" + AppId + "&component_access_token=" + accessTokenValue);
            //if (jsonStr.Contains("errcode"))
            //{
            //    response.Content = new StringContent(jsonStr, Encoding.UTF8, "text/html");
            //    return response;
            //}
            JObject result = Newtonsoft.Json.JsonConvert.DeserializeObject<JObject>(jsonStr);
            string openid = result["openid"].Value<string>();
            if (clienturl.IndexOf("?") != -1)
                return Redirect(OAuthCallback + clienturl + "&errcode=0&openid=" + openid);
            else
                return Redirect(OAuthCallback + clienturl + "?errcode=0&openid=" + openid);
        }

 注意：由第三方平台授权的网页授权，不需要将“公众号设置->功能设置->网页授权域名”特地设置为返回url对应的域名。