C#微信公众平台开发之access_token的获取存储与更新

#region 请求Url，不发送数据
/// <summary>
/// 请求Url，不发送数据
/// </summary>
public static string RequestUrl(string url)
{
 return RequestUrl(url, "POST");
}
#endregion

#region 请求Url，不发送数据
/// <summary>
/// 请求Url，不发送数据
/// </summary>
public static string RequestUrl(string url, string method)
{
 // 设置参数
 HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
 CookieContainer cookieContainer = new CookieContainer();
 request.CookieContainer = cookieContainer;
 request.AllowAutoRedirect = true;
 request.Method = method;
 request.ContentType = "text/html";
 request.Headers.Add("charset", "utf-8");

 //发送请求并获取相应回应数据
 HttpWebResponse response = request.GetResponse() as HttpWebResponse;
 //直到request.GetResponse()程序才开始向目标网页发送Post请求
 Stream responseStream = response.GetResponseStream();
 StreamReader sr = new StreamReader(responseStream, Encoding.UTF8);
 //返回结果网页（html）代码
 string content = sr.ReadToEnd();
 return content;
}
#endregion

namespace SWX.Utils
{
 /// <summary>
 /// 工具类
 /// </summary>
 public class Tools
 {
  #region 获取Json字符串某节点的值
  /// <summary>
  /// 获取Json字符串某节点的值
  /// </summary>
  public static string GetJsonValue(string jsonStr, string key)
  {
   string result = string.Empty;
   if (!string.IsNullOrEmpty(jsonStr))
   {
    key = "\"" + key.Trim('"') + "\"";
    int index = jsonStr.IndexOf(key) + key.Length + 1;
    if (index > key.Length + 1)
    {
     //先截逗号，若是最后一个，截“｝”号，取最小值
     int end = jsonStr.IndexOf(',', index);
     if (end == -1)
     {
      end = jsonStr.IndexOf('}', index);
     }

     result = jsonStr.Substring(index, end - index);
     result = result.Trim(new char[] { '"', ' ', '\'' }); //过滤引号或空格
    }
   }
   return result;
  }
  #endregion

 }
}

#region 验证Token是否过期
/// <summary>
/// 验证Token是否过期
/// </summary>
public static bool TokenExpired(string access_token)
{
 string jsonStr = HttpRequestUtil.RequestUrl(string.Format("https://api.weixin.qq.com/cgi-bin/menu/get?access_token={0}", access_token));
 if (Tools.GetJsonValue(jsonStr, "errcode") == "42001")
 {
  return true;
 }
 return false;
}
#endregion

#region 获取Token
/// <summary>
/// 获取Token
/// </summary>
public static string GetToken(string appid, string secret)
{
 string strJson = HttpRequestUtil.RequestUrl(string.Format("https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid={0}&secret={1}", appid, secret));
 return Tools.GetJsonValue(strJson, "access_token");
}
#endregion

#region 获取access_token
/// <summary>
/// 获取access_token
/// </summary>
public static string GetAccessToken(PageBase page)
{
 string access_token = string.Empty;

 UserInfo user = GetLoginUser(page);
 if (user != null)
 {
  if (string.IsNullOrWhiteSpace(user.access_token)) //尚未保存过access_token
  {
   access_token = WXApi.GetToken(user.AppID, user.AppSecret);
  }
  else
  {
   if (WXApi.TokenExpired(user.access_token)) //access_token过期
   {
    access_token = WXApi.GetToken(user.AppID, user.AppSecret);
   }
   else
   {
    return user.access_token;
   }
  }

  MSSQLHelper.ExecuteSql(string.Format("update SWX_Config set access_token='{0}' where UserName='{1}'", access_token, user.UserName));
 }

 return access_token;
}
#endregion