C#微信公眾平台開發—高級群發接口，
涉及access_token的獲取請參考《C#微信公眾平台開發—access_token的獲取存儲與更新》
一、為了實現高級群發功能，需要解決的問題
1、通過微信接口上傳圖文消息素材時，Json中的圖片不是url而是media_id，如何通過微信接口上傳圖片並獲取圖片的media_id？
2、圖片存儲在什麼地方，如何獲取？
二、實現步驟，以根據OpenID列表群發圖文消息為例
1、准備數據
我把數據存儲在數據庫中，ImgUrl字段是圖片在服務器上的相對路徑(這裡的服務器是自己的服務器，不是微信的哦)。
從數據庫中獲取數據放到DataTable中：
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DataTable dt = ImgItemDal.GetImgItemTable(loginUser.OrgID, data);
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2、通過微信接口上傳圖片，返回圖片的media_id
取ImgUrl字段數據，通過MapPath方法獲取圖片在服務器上的物理地址，用FileStream類讀取圖片，並上傳給微信
HTTP上傳文件代碼(HttpRequestUtil類)：
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/// <summary>
/// Http上傳文件
/// </summary>
public static string HttpUploadFile(string url, string path)
{
// 設置參數
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"); // 隨機分隔線
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);
//請求頭部信息
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();
//發送請求並獲取相應回應數據
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
//直到request.GetResponse()程序才開始向目標網頁發送Post請求
Stream instream = response.GetResponseStream();
StreamReader sr = new StreamReader(instream, Encoding.UTF8);
//返回結果網頁（html）代碼
string content = sr.ReadToEnd();
return content;
}
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請求微信接口，上傳圖片，返回media_id(WXApi類)：
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/// <summary>
/// 上傳媒體返回媒體ID
/// </summary>
public static string UploadMedia(string access_token, string type, string path)
{
// 設置參數
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); // 上圖片返回媒體ID
string media_id = Tools.GetJsonValue(msg, "media_id");
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傳入的path(aspx.cs文件中的代碼)：
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string path = MapPath(data);
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一個圖文消息由若干條圖文組成，每條圖文有標題、內容、鏈接、圖片等
遍歷每條圖文數據，分別請求微信接口，上傳圖片，獲取media_id
3、上傳圖文消息素材
拼接圖文消息素材Json字符串(ImgItemDal類(操作圖文消息表的類))：
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/// <summary>
/// 拼接圖文消息素材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\":\"要發送的圖片不存在\"}";
}
string msg = WXApi.UploadMedia(access_token, "image", path); // 上圖片返回媒體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();
}
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上傳圖文消息素材，獲取圖文消息的media_id：
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/// <summary>
/// 請求Url，發送數據
/// </summary>
public static string PostUrl(string url, string postData)
{
byte[] data = Encoding.UTF8.GetBytes(postData);
// 設置參數
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();
//發送請求並獲取相應回應數據
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
//直到request.GetResponse()程序才開始向目標網頁發送Post請求
Stream instream = response.GetResponseStream();
StreamReader sr = new StreamReader(instream, Encoding.UTF8);
//返回結果網頁（html）代碼
string content = sr.ReadToEnd();
return content;
}
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/// <summary>
/// 上傳圖文消息素材返回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");
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4、群發圖文消息
獲取全部關注者OpenID集合(WXApi類)：
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/// <summary>
/// 獲取關注者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>
/// 獲取關注者OpenID集合
/// </summary>
public static List<string> GetOpenIDs(string access_token, string next_openid)
{
// 設置參數
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>();
}
}
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List<string> openidList = WXApi.GetOpenIDs(access_token); //獲取關注者OpenID列表
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拼接圖文消息Json(WXMsgUtil類)：
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/// <summary>
/// 圖文消息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();
}
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群發代碼：
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resultMsg = WXApi.Send(access_token, WXMsgUtil.CreateNewsJson(newsid, openidList));
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/// <summary>
/// 根據OpenID列表群發
/// </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);
}
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供群發按鈕調用的方法(data是傳到頁面的id，根據它從數據庫中取數據)：
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/// <summary>
/// 群發
/// </summary>
public string Send()
{
string type = Request["type"];
string data = Request["data"];
string access_token = AdminUtil.GetAccessToken(this); //獲取access_token
List<string> openidList = WXApi.GetOpenIDs(access_token); //獲取關注者OpenID列表
UserInfo loginUser = AdminUtil.GetLoginUser(this); //當前登錄用戶
string resultMsg = null;
//發送文本
if (type == "1")
{
resultMsg = WXApi.Send(access_token, WXMsgUtil.CreateTextJson(data, openidList));
}
//發送圖片
if (type == "2")
{
string path = MapPath(data);
if (!File.Exists(path))
{
return "{\"code\":0,\"msg\":\"要發送的圖片不存在\"}";
}
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));
}
//發送圖文消息
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));
}
//結果處理
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參數錯誤\"}";
}
}
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C#微信公眾平台開發源碼在我的博客首頁左側下面
