涉及access_token的获取请参考《c#微信公众平台开发之access_token的获取存储与更新》
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)：
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/// <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("\r\n--" + boundary + "\r\n"); byte[] endboundarybytes = encoding.utf8.getbytes("\r\n--" + boundary + "--\r\n"); 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}\"\r\ncontent-type:application/octet-stream\r\n\r\n", 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)：
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/// <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);} |
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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))：
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/// <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id string 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：
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/// <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;} |
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/// <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);} |
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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)：
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/// <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>(); }} |
list<string> openidlist = wxapi.getopenids(access_token); //获取关注者openid列表
拼接图文消息json(wxmsgutil类)：
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/// <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：
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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)：
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/// <summary>/// 群发/// </summary>public string send(){ string type = request["type"]; string data = request["data"]; string access_token = adminutil.getaccesstoken(this); //获取access_token list<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\"}"; }} |
以上就是本文的全部内容，希望对大家的学习有所帮助。
