C#微信公眾平臺開發—高階群發介面

秋荷雨翔的部落格發表於2014-11-19
C#

涉及access_token的獲取請參考《C#微信公眾平臺開發—access_token的獲取儲存與更新》

一、為了實現高階群發功能，需要解決的問題

1、通過微信介面上傳圖文訊息素材時，Json中的圖片不是url而是media_id，如何通過微信介面上傳圖片並獲取圖片的media_id？

2、圖片儲存在什麼地方，如何獲取？

二、實現步驟，以根據OpenID列表群發圖文訊息為例

1、準備資料

我把資料儲存在資料庫中，ImgUrl欄位是圖片在伺服器上的相對路徑(這裡的伺服器是自己的伺服器，不是微信的哦)。

從資料庫中獲取資料放到DataTable中：

DataTable dt = ImgItemDal.GetImgItemTable(loginUser.OrgID, data);

2、通過微信介面上傳圖片，返回圖片的media_id

取ImgUrl欄位資料，通過MapPath方法獲取圖片在伺服器上的實體地址，用FileStream類讀取圖片，並上傳給微信

HTTP上傳檔案程式碼(HttpRequestUtil類)：

/// <summary>
/// Http上傳檔案
/// </summary>
public static string HttpUploadFile(string url, string path)
{
    // 設定引數
    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);

    //請求頭部資訊 
    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();

    //傳送請求並獲取相應回應資料
    HttpWebResponse response = request.GetResponse() as HttpWebResponse;
    //直到request.GetResponse()程式才開始向目標網頁傳送Post請求
    Stream instream = response.GetResponseStream();
    StreamReader sr = new StreamReader(instream, Encoding.UTF8);
    //返回結果網頁（html）程式碼
    string content = sr.ReadToEnd();
    return content;
}

請求微信介面，上傳圖片，返回media_id(WXApi類)：

/// <summary>
/// 上傳媒體返回媒體ID
/// </summary>
public static string UploadMedia(string access_token, string type, string path)
{
    // 設定引數
    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);
}
string msg = WXApi.UploadMedia(access_token, "image", path); // 上圖片返回媒體ID
string media_id = Tools.GetJsonValue(msg, "media_id");

傳入的path(aspx.cs檔案中的程式碼)：

string path = MapPath(data);

一個圖文訊息由若干條圖文組成，每條圖文有標題、內容、連結、圖片等

遍歷每條圖文資料，分別請求微信介面，上傳圖片，獲取media_id

3、上傳圖文訊息素材

拼接圖文訊息素材Json字串(ImgItemDal類(操作圖文訊息表的類))：

/// <summary>
/// 拼接圖文訊息素材Json字串
/// </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\":\"要傳送的圖片不存在\"}";
        }
        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();
}

上傳圖文訊息素材，獲取圖文訊息的media_id：

/// <summary>
/// 請求Url，傳送資料
/// </summary>
public static string PostUrl(string url, string postData)
{
    byte[] data = Encoding.UTF8.GetBytes(postData);

    // 設定引數
    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();

    //傳送請求並獲取相應回應資料
    HttpWebResponse response = request.GetResponse() as HttpWebResponse;
    //直到request.GetResponse()程式才開始向目標網頁傳送Post請求
    Stream instream = response.GetResponseStream();
    StreamReader sr = new StreamReader(instream, Encoding.UTF8);
    //返回結果網頁（html）程式碼
    string content = sr.ReadToEnd();
    return content;
}
/// <summary>
/// 上傳圖文訊息素材返回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、群發圖文訊息

獲取全部關注者OpenID集合(WXApi類)：

/// <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)
{
    // 設定引數
    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>();
    }
}
List<string> openidList = WXApi.GetOpenIDs(access_token); //獲取關注者OpenID列表

拼接圖文訊息Json(WXMsgUtil類)：

/// <summary>
/// 圖文訊息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();
}

群發程式碼：

resultMsg = WXApi.Send(access_token, WXMsgUtil.CreateNewsJson(newsid, openidList));
/// <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);
}

供群發按鈕呼叫的方法(data是傳到頁面的id，根據它從資料庫中取資料)：

/// <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); //當前登入使用者 

    string resultMsg = null;

    //傳送文字
    if (type == "1")
    {
        resultMsg = WXApi.Send(access_token, WXMsgUtil.CreateTextJson(data, openidList));
    }

    //傳送圖片
    if (type == "2")
    {
        string path = MapPath(data);
        if (!File.Exists(path))
        {
            return "{\"code\":0,\"msg\":\"要傳送的圖片不存在\"}";
        }
        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));
    }

    //傳送圖文訊息
    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引數錯誤\"}";
    }
}

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