1. What is access_token?
access_token is the globally unique ticket of the public account. The public account needs to use access_token when calling each interface. Under normal circumstances, the access_token is valid for 7200 seconds. Repeated acquisition will cause the last access_token to become invalid. Since the number of API calls to obtain access_token is very limited, it is recommended that developers store and update access_token globally. Frequent refresh of access_token will limit API calls and affect their own business.
2. Problems to be solved
1. How to obtain access_token.
2. Since the validity period of access_token is 7200 seconds, that is, 2 hours, and repeated acquisition will cause the last access_token to become invalid, the number of api calls to obtain access_token is very limited, so it is necessary to solve how to globally store and update access_token. .
3. Ideas
1. Store access_token in the database.
2. When will the access_token be updated? Update when access_token expires, so how to determine whether access_token has expired? Use the current access_token to request the WeChat interface to obtain the custom menu. If the returned errcode is 42001, it means that the access_token has expired. At this time, obtain the access_token again.
Database design (table name SWX_Config):
4. Code:
1. Http request code (HttpRequestUtil class):
#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
2. Auxiliary method (Tools class):
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 } }
3. Determine whether access_token has expired (WXApi class):
#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
4. Request the WeChat interface to obtain access_token (WXApi Class):
#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
5. Global storage and update access_token (AdminUtil class):
#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
The above is the entire content of this article. I hope it will be helpful to everyone in the development of WeChat public platform.
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