C#微信公众平台开发—高级群发接口

一、为了实现高级群发功能，需要解决的问题

1、通过微信接口上传图文消息素材时，Json中的图片不是url而是media_id，如何通过微信接口上传图片并获取图片的media_id？

2、图片存储在什么地方，如何获取？

二、实现步骤，以根据OpenID列表群发图文消息为例

1、准备数据

我把数据存储在数据库中，ImgUrl字段是图片在服务器上的相对路径(这里的服务器是自己的服务器，不是微信的哦)。

从数据库中获取数据放到DataTable中：DataTable dt = ImgItemDal.GetImgItemTable(loginUser.OrgID, data);2、通过微信接口上传图片，返回图片的media_id

取ImgUrl字段数据，通过MapPath方法获取图片在服务器上的物理地址，用FileStream类读取图片，并上传给微信

HTTP上传文件代码(HttpRequestUtil类)：/// <summary>/// Http上传文件/// </summary>public static string HttpUploadFile(string url, string path){// 设置参数HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;CookieContainer cookieContainer = new CookieContainer();request.CookieContainer = cookieContainer;request.AllowAutoRedirect = true;request.Method = "POST";string boundary = DateTime.Now.Ticks.ToString("X"); // 随机分隔线request.ContentType = "multipart/form-data;charset=utf-8;boundary=" + boundary;byte[] itemBoundaryBytes = Encoding.UTF8.GetBytes("rn--" + boundary + "rn");byte[] endBoundaryBytes = Encoding.UTF8.GetBytes("rn--" + boundary + "--rn");int pos = path.LastIndexOf("\");string fileName = path.Substring(pos + 1);//请求头部信息StringBuilder sbHeader = new StringBuilder(string.Format("Content-Disposition:form-data;name="file";filename="{0}"rnContent-Type:application/octet-streamrnrn", fileName));byte[] postHeaderBytes = Encoding.UTF8.GetBytes(sbHeader.ToString());FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read);byte[] bArr = new byte[fs.Length];fs.Read(bArr, 0, bArr.Length);fs.Close();Stream postStream = request.GetRequestStream();postStream.Write(itemBoundaryBytes, 0, itemBoundaryBytes.Length);postStream.Write(postHeaderBytes, 0, postHeaderBytes.Length);postStream.Write(bArr, 0, bArr.Length);postStream.Write(endBoundaryBytes, 0, endBoundaryBytes.Length);postStream.Close();//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 instream = response.GetResponseStream();StreamReader sr = new StreamReader(instream, Encoding.UTF8);//返回结果网页（html）代码string content = sr.ReadToEnd();return content;}请求微信接口，上传图片，返回media_id(WXApi类)：/// <summary>/// 上传媒体返回媒体ID/// </summary>public static string UploadMedia(string access_token, string type, string path){// 设置参数string url = string.Format("http://file.api.weixin.qq.com/cgi-bin/media/upload?access_token={0}&type={1}", access_token, type);return HttpRequestUtil.HttpUploadFile(url, path);}string msg = WXApi.UploadMedia(access_token, "image", path); // 上图片返回媒体IDstring media_id = Tools.GetJsonValue(msg, "media_id");传入的path(aspx.cs文件中的代码)：string path = MapPath(data);一个图文消息由若干条图文组成，每条图文有标题、内容、链接、图片等

遍历每条图文数据，分别请求微信接口，上传图片，获取media_id

3、上传图文消息素材

拼接图文消息素材Json字符串(ImgItemDal类(操作图文消息表的类))：/// <summary>/// 拼接图文消息素材Json字符串/// </summary>public static string GetArticlesJsonStr(PageBase page, string access_token, DataTable dt){StringBuilder sbArticlesJson = new StringBuilder();sbArticlesJson.Append("{"articles":[");int i = 0;foreach (DataRow dr in dt.Rows){string path = page.MapPath(dr["ImgUrl"].ToString());if (!File.Exists(path)){return "{"code":0,"msg":"要发送的图片不存在"}";}string msg = WXApi.UploadMedia(access_token, "image", path); // 上图片返回媒体IDstring media_id = Tools.GetJsonValue(msg, "media_id");sbArticlesJson.Append("{");sbArticlesJson.Append(""thumb_media_id":"" + media_id + "",");sbArticlesJson.Append(""author":"" + dr["Author"].ToString() + "",");sbArticlesJson.Append(""title":"" + dr["Title"].ToString() + "",");sbArticlesJson.Append(""content_source_url":"" + dr["TextUrl"].ToString() + "",");sbArticlesJson.Append(""content":"" + dr["Content"].ToString() + "",");sbArticlesJson.Append(""digest":"" + dr["Content"].ToString() + "",");if (i == dt.Rows.Count - 1){sbArticlesJson.Append(""show_cover_pic":"1"}");}else{sbArticlesJson.Append(""show_cover_pic":"1"},");}i++;}sbArticlesJson.Append("]}");return sbArticlesJson.ToString();}上传图文消息素材，获取图文消息的media_id：/// <summary>/// 请求Url，发送数据/// </summary>public static string PostUrl(string url, string postData){byte[] data = Encoding.UTF8.GetBytes(postData);// 设置参数HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;CookieContainer cookieContainer = new CookieContainer();request.CookieContainer = cookieContainer;request.AllowAutoRedirect = true;request.Method = "POST";request.ContentType = "application/x-www-form-urlencoded";request.ContentLength = data.Length;Stream outstream = request.GetRequestStream();outstream.Write(data, 0, data.Length);outstream.Close();//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 instream = response.GetResponseStream();StreamReader sr = new StreamReader(instream, Encoding.UTF8);//返回结果网页（html）代码string content = sr.ReadToEnd();return content;}/// <summary>/// 上传图文消息素材返回media_id/// </summary>public static string UploadNews(string access_token, string postData){return HttpRequestUtil.PostUrl(string.Format("https://api.weixin.qq.com/cgi-bin/media/uploadnews?access_token={0}", access_token), postData);}string articlesJson = ImgItemDal.GetArticlesJsonStr(this, access_token, dt);string newsMsg = WXApi.UploadNews(access_token, articlesJson);string newsid = Tools.GetJsonValue(newsMsg, "media_id"); 4、群发图文消息

获取全部关注者OpenID集合(WXApi类)：/// <summary>/// 获取关注者OpenID集合/// </summary>public static List<string> GetOpenIDs(string access_token){List<string> result = new List<string>();List<string> openidList = GetOpenIDs(access_token, null);result.AddRange(openidList);while (openidList.Count > 0){openidList = GetOpenIDs(access_token, openidList[openidList.Count - 1]);result.AddRange(openidList);}return result;}/// <summary>/// 获取关注者OpenID集合/// </summary>public static List<string> GetOpenIDs(string access_token, string next_openid){// 设置参数string url = string.Format("https://api.weixin.qq.com/cgi-bin/user/get?access_token={0}&next_openid={1}", access_token, string.IsNullOrWhiteSpace(next_openid) ? "" : next_openid);string returnStr = HttpRequestUtil.RequestUrl(url);int count = int.Parse(Tools.GetJsonValue(returnStr, "count"));if (count > 0){string startFlg = ""openid":[";int start = returnStr.IndexOf(startFlg) + startFlg.Length;int end = returnStr.IndexOf("]", start);string openids = returnStr.Substring(start, end - start).Replace(""", "");return openids.Split(',').ToList<string>();}else{return new List<string>();}}拼接图文消息Json(WXMsgUtil类)：/// <summary>/// 图文消息json/// </summary>public static string CreateNewsJson(string media_id, List<string> openidList){StringBuilder sb = new StringBuilder();sb.Append("{"touser":[");sb.Append(string.Join(",", openidList.ConvertAll<string>(a => """ + a + """).ToArray()));sb.Append("],");sb.Append(""msgtype":"mpnews",");sb.Append(""mpnews":{"media_id":"" + media_id + ""}");sb.Append("}");return sb.ToString();}群发代码：resultMsg = WXApi.Send(access_token, WXMsgUtil.CreateNewsJson(newsid, openidList));/// <summary>/// 根据OpenID列表群发/// </summary>public static string Send(string access_token, string postData){return HttpRequestUtil.PostUrl(string.Format("https://api.weixin.qq.com/cgi-bin/message/mass/send?access_token={0}", access_token), postData);} 供群发按钮调用的方法(data是传到页面的id，根据它从数据库中取数据)：/// <summary>/// 群发/// </summary>public string Send(){string type = Request["type"];string data = Request["data"];string access_token = AdminUtil.GetAccessToken(this); //获取access_tokenList<string> openidList = WXApi.GetOpenIDs(access_token); //获取关注者OpenID列表UserInfo loginUser = AdminUtil.GetLoginUser(this); //当前登录用户string resultMsg = null;//发送文本if (type == "1"){resultMsg = WXApi.Send(access_token, WXMsgUtil.CreateTextJson(data, openidList));}//发送图片if (type == "2"){string path = MapPath(data);if (!File.Exists(path)){return "{"code":0,"msg":"要发送的图片不存在"}";}string msg = WXApi.UploadMedia(access_token, "image", path);string media_id = Tools.GetJsonValue(msg, "media_id");resultMsg = WXApi.Send(access_token, WXMsgUtil.CreateImageJson(media_id, openidList));}//发送图文消息if (type == "3"){DataTable dt = ImgItemDal.GetImgItemTable(loginUser.OrgID, data);string articlesJson = ImgItemDal.GetArticlesJsonStr(this, access_token, dt);string newsMsg = WXApi.UploadNews(access_token, articlesJson);string newsid = Tools.GetJsonValue(newsMsg, "media_id");resultMsg = WXApi.Send(access_token, WXMsgUtil.CreateNewsJson(newsid, openidList));}//结果处理if (!string.IsNullOrWhiteSpace(resultMsg)){string errcode = Tools.GetJsonValue(resultMsg, "errcode");string errmsg = Tools.GetJsonValue(resultMsg, "errmsg");if (errcode == "0"){return "{"code":1,"msg":""}";}else{return "{"code":0,"msg":"errcode:"+ errcode + ", errmsg:"+ errmsg + ""}";}}else{return "{"code":0,"msg":"type参数错误"}";}}更多C#微信公众平台开发—高级群发接口相关文章请关注PHP中文网！