最近项目移动端需要实现微信自定义分享功能，包含分享自定义标题、描述等。
- 首先到公众号的后台，功能设置里面，添加将要被分享的域名，如图
- 后端签名算法实现 ，参考腾讯开发者文档https://mp.weixin.qq.com/wiki?t=resource/res_main&id=mp1421141115
jsapi_ticket
生成签名之前必须先了解一下jsapi_ticket，jsapi_ticket是公众号用于调用微信JS接口的临时票据。正常情况下，jsapi_ticket的有效期为7200秒，通过access_token来获取。由于获取jsapi_ticket的api调用次数非常有限，频繁刷新jsapi_ticket会导致api调用受限，影响自身业务，开发者必须在自己的服务全局缓存jsapi_ticket 。
生成签名步骤，获取AccessToken-》获取JsApiTicket-》生成签名
appsettings配置文件添加配置
"Api": {
"JSJDKBaseApi": "https://api.weixin.qq.com/cgi-bin"
},
"JSJDK": {
"AppId": "***",
"Secret": "****"
}
- 创建签名公用类
public class JSSDKSignHelper { private static AccessTokenResponse singleAccessToken; private string _tencentApi { get; set; } private string _appid { get; set; } private string _appSecret { get; set; } public JSSDKSignHelper(IConfiguration config) { _tencentApi = config["Api:JSJDKBaseApi"]; _appid = config["JSJDK:AppId"]; _appSecret = config["JSJDK:Secret"]; } public string GetAccessTokenSingle(out bool isNewObj) { isNewObj = false; if (singleAccessToken != null && (singleAccessToken.expire_out > DateTime.Now.AddHours(2))) { return singleAccessToken.access_token; } else { var response = GetAccessToken(); if (response.errcode == 0) { response.expire_out = DateTime.Now.AddHours(expireHour); singleAccessToken = response; isNewObj = true; return response?.access_token; } } return null; } /// <summary> /// 获取access_token /// </summary> /// <returns></returns> private AccessTokenResponse GetAccessToken() { string url = _tencentApi + "/token?grant_type=client_credential&appid=" + _appid + "&secret=" + _appSecret; var response = ApiClient.GetJson<AccessTokenResponse>(url); return response; } /// <summary> /// 获取JsApiTicket /// </summary> /// <param name="accessToken"></param> /// <returns></returns> public string GetJsApiTicket(string accessToken) { if (string.IsNullOrWhiteSpace(accessToken)) { return null; } string url = _tencentApi + $"/ticket/getticket?type=jsapi&access_token={accessToken}"; var response = ApiClient.GetJson<AccessTicketResponse>(url); return response?.ticket; } /// <summary> /// 获取签名 /// </summary> /// <param name="jsapi_ticket"></param> /// <param name="noncestr">随机字符串(必须与wx.config中的nonceStr相同)</param> /// <param name="timestamp">时间戳(必须与wx.config中的timestamp相同)</param> /// <param name="url">当前网页的URL，不包含#及其后面部分(必须是调用JS接口页面的完整URL)</param> /// <returns></returns> public string GetSignature(string jsapi_ticket, string noncestr, string timestamp, string url) { if (string.IsNullOrEmpty(jsapi_ticket) || string.IsNullOrEmpty(noncestr) || string.IsNullOrEmpty(timestamp) || string.IsNullOrEmpty(url)) return null; var string1Builder = new StringBuilder(); string1Builder.Append("jsapi_ticket=").Append(jsapi_ticket).Append("&") .Append("noncestr=").Append(noncestr).Append("&") .Append("timestamp=").Append(timestamp).Append("&") .Append("url=").Append(url.IndexOf("#") >= 0 ? url.Substring(0, url.IndexOf("#")) : url); return Sha1Sign(string1Builder.ToString()); } /// <summary> /// Sha1加密签名 /// </summary> /// <param name="str"></param> /// <returns></returns> public string Sha1Sign(string str) { SHA1 sha1 = new SHA1CryptoServiceProvider(); byte[] bytes_sha1_in = System.Text.UTF8Encoding.Default.GetBytes(str); byte[] bytes_sha1_out = sha1.ComputeHash(bytes_sha1_in); string signature = BitConverter.ToString(bytes_sha1_out); signature = signature.Replace("-", "").ToLower(); return signature; } }
- 签名定义的Model
public class AccessTokenResponse: BaseResponse { /// <summary> /// 返回access_token值，有效期7200秒 /// </summary> public string access_token { get; set; } /// <summary> /// 过期时间，单位小时 /// </summary> public DateTime expire_out { get; set; } } public class AccessTicketResponse : BaseResponse { /// <summary> /// 返回Ticket票据，有效期7200秒 /// </summary> public string ticket { get; set; } } public class BaseResponse { /// <summary> /// 过期时间，单位秒 /// </summary> public string expire_in { get; set; } /// <summary> /// 错误代码 /// </summary> public Int32 errcode { get; set; } /// <summary> /// 错误信息描述 /// </summary> public string errmsg { get; set; } }
- 创建生成签名的时间戳和随机串
/// <summary> /// 获取微信JS-JDK时间戳 /// </summary> /// <returns></returns> public static string GetTimeStamp() { TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0); return Convert.ToInt64(ts.TotalSeconds).ToString(); } /// <summary> /// JS-JDK 创建随机字符串 /// </summary> /// <returns></returns> public static string CreatenNonce_str() { Random r = new Random(); var sb = new StringBuilder(); var length = strs.Length; for (int i = 0; i < 15; i++) { sb.Append(strs[r.Next(length - 1)]); } return sb.ToString(); }
- Action中实际调用
[HttpPost] [Route("GetSignature")] public string GetSignature(string url= "http://www.sina.cn/") { try { if (string.IsNullOrEmpty(url)) return "url不能为空"; string _jsTicket = null, _signature = null; string _accessToken = _jsSignHelper.GetAccessTokenSingle(out bool isNewObj); WxConfigModel model = new WxConfigModel(); model.AppId = appId; model.TimeStamp = MyUtil.GetTimeStamp(); model.NonceStr = MyUtil.CreatenNonce_str(); if (isNewObj|| _wxConfigModel.Signature==null) { _jsTicket = _jsSignHelper.GetJsApiTicket(_accessToken); _signature = _jsSignHelper.GetSignature(_jsTicket, model.NonceStr, model.TimeStamp, url); model.jsTicket = _jsTicket; model.Signature = _signature; _wxConfigModel = model; } return JsonConvert.SerializeObject(model); } catch (Exception ex) { throw ex; } }
注意：
- 签名用的noncestr和timestamp必须与wx.config中的nonceStr和timestamp相同。
- 移动端分享时，不能本地测试，需要发布到外网测试，否则报签名错误
- 生成的签名，可以实用校验工具校验是否正确。https://mp.weixin.qq.com/debug/cgi-bin/sandbox?t=jsapisign