微信公眾平台向特定用戶推送消息

最近研究微信公眾平台，這里整理了一下向特定用戶推送消息的思路

一、首先需要將微信的openid與系統用戶綁定。

在用戶關注公眾平台的時候，回復一個鏈接，要求用戶綁定，可以設計如下消息進行回復，（openid最好進行加密處理，后者還需要用這個字段綁定fakeid）。

歡迎關注有問必答平台,<a href='http://myweixin123.duapp.com/bind.html?openid=@openid'>點擊此處進行用戶綁定</a>! 

在bind.html頁面將openid與系統的usercode進行綁定，這個綁定過程非常簡單，這里不詳敘述。

二、將openid與fakeid進行綁定

微信公眾平台是一回一答的模式；但是在微信公眾平台后台，可以向特定用戶進行消息發送。我們利用這個機制使用代碼去模擬這個過程來實現消息推送。

首先需要模擬登錄：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Security.Cryptography;
using System.Text;
using System.Net;
using System.IO;
using System.Security.Authentication;
using System.Security.Cryptography.X509Certificates;
/// <summary>
///WeiXinLogin 的摘要說明
/// </summary>
public class WeiXinLogin
{
   
    /// <summary>
    /// MD5　32位加密
    /// </summary>
    /// <param name="str"></param>
    /// <returns></returns>
    static string GetMd5Str32(string str)
    {
        MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider();
        // Convert the input string to a byte array and compute the hash.  
        char[] temp = str.ToCharArray();
        byte[] buf = new byte[temp.Length];
        for (int i = 0; i < temp.Length; i++)
        {
            buf[i] = (byte)temp[i];
        }
        byte[] data = md5Hasher.ComputeHash(buf);
        // Create a new Stringbuilder to collect the bytes  
        // and create a string.  
        StringBuilder sBuilder = new StringBuilder();
        // Loop through each byte of the hashed data   
        // and format each one as a hexadecimal string.  
        for (int i = 0; i < data.Length; i++)
        {
            sBuilder.Append(data[i].ToString("x2"));
        }
        // Return the hexadecimal string.  
        return sBuilder.ToString();
    }

    public static bool ExecLogin(string name,string pass)
    {
        bool result = false;
        string password = GetMd5Str32(pass).ToUpper(); 
        string padata = "username=" + name + "&pwd=" + password + "&imgcode=&f=json";
        string url = "https://mp.weixin.qq.com/cgi-bin/login?lang=zh_CN ";//請求登錄的URL
        try
        {
            CookieContainer cc = new CookieContainer();//接收緩存
            byte[] byteArray = Encoding.UTF8.GetBytes(padata); // 轉化
            HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(url);  //新建一個WebRequest對象用來請求或者響應url
            ServicePointManager.CertificatePolicy = new AcceptAllCertificatePolicy(); 

            webRequest2.CookieContainer = cc;                                      //保存cookie  
            webRequest2.Method = "POST";                                          //請求方式是POST
            webRequest2.UserAgent = "Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/30.0.1599.69 Safari/537.36";
            webRequest2.Referer = "https://mp.weixin.qq.com/";
            webRequest2.ContentType = "application/x-www-form-urlencoded";       //請求的內容格式為application/x-www-form-urlencoded
            webRequest2.ContentLength = byteArray.Length;
            Stream newStream = webRequest2.GetRequestStream();           //返回用於將數據寫入 Internet 資源的 Stream。
            // Send the data.
            newStream.Write(byteArray, 0, byteArray.Length);    //寫入參數
            newStream.Close();
            HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();
            StreamReader sr2 = new StreamReader(response2.GetResponseStream(), Encoding.Default);
            string text2 = sr2.ReadToEnd();

            //此處用到了newtonsoft來序列化
            WeiXinRetInfo retinfo = Newtonsoft.Json.JsonConvert.DeserializeObject<WeiXinRetInfo>(text2);
            string token = string.Empty;
            if (retinfo.ErrMsg.Length > 0)
            {
                token = retinfo.ErrMsg.Split(new char[] { '&' })[2].Split(new char[] { '=' })[1].ToString();//取得令牌
                LoginInfo.LoginCookie = cc;
                LoginInfo.CreateDate = DateTime.Now;
                LoginInfo.Token = token;
                result = true;
            }
        }
        catch (Exception ex)
        {
          
            throw new Exception(ex.StackTrace);
        }
        return result;
    }

    public static class LoginInfo
    {
        /// <summary>
        /// 登錄后得到的令牌
        /// </summary>        
        public static string Token { get; set; }
        /// <summary>
        /// 登錄后得到的cookie
        /// </summary>
        public static CookieContainer LoginCookie { get; set; }
        /// <summary>
        /// 創建時間
        /// </summary>
        public static DateTime CreateDate { get; set; }

    }
    internal class AcceptAllCertificatePolicy : ICertificatePolicy
    {
        public AcceptAllCertificatePolicy()
        {
        }

        public bool CheckValidationResult(ServicePoint sPoint,
           X509Certificate cert, WebRequest wRequest, int certProb)
        {
            // Always accept  
            return true;
        }
    }  
}

獲取fakeid

    public static ArrayList SubscribeMP()
    {

        try
        {
            CookieContainer cookie = null;
            string token = null;


            cookie = WeiXinLogin.LoginInfo.LoginCookie;//取得cookie
            token = WeiXinLogin.LoginInfo.Token;//取得token

            /*獲取用戶信息的url，這里有幾個參數給大家講一下，1.token此參數為上面的token 2.pagesize此參數為每一頁顯示的記錄條數

            3.pageid為當前的頁數，4.groupid為微信公眾平台的用戶分組的組id，當然這也是我的猜想不一定正確*/
            string Url = "https://mp.weixin.qq.com/cgi-bin/contactmanage?t=user/index&pagesize=10&pageidx=0&type=0&groupid=0&token=" + token + "&lang=zh_CN";
            HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(Url);
            webRequest2.CookieContainer = cookie;
            webRequest2.ContentType = "text/html; charset=UTF-8";
            webRequest2.Method = "GET";
            webRequest2.UserAgent = "Mozilla/5.0 (Windows NT 5.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1";
            webRequest2.ContentType = "application/x-www-form-urlencoded";
            HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();
            StreamReader sr2 = new StreamReader(response2.GetResponseStream(), Encoding.Default);
            string text2 = sr2.ReadToEnd();


            MatchCollection mc;

            //由於此方法獲取過來的信息是一個html網頁所以此處使用了正則表達式，注意：（此正則表達式只是獲取了fakeid的信息如果想獲得一些其他的信息修改此處的正則表達式就可以了。）
            Regex r = new Regex("\"id\"\\:\\d+,\"nick_name\""); //定義一個Regex對象實例
            mc = r.Matches(text2);
            Int32 friendSum = mc.Count;          //好友總數

            string fackID = "";

            ArrayList fackID1 = new ArrayList();

            for (int i = 0; i < friendSum; i++)
            {
                //"id":208989515,"nick_name"
                fackID = mc[i].Value.Replace(",\"nick_name\"", "").Split(new char[] { ':' })[1];
                fackID = fackID.Replace("\"", "").Trim();
                fackID1.Add(fackID);
            }

            return fackID1;



        }
        catch (Exception ex)
        {
            throw new Exception(ex.StackTrace);
        }
    }

根據fakeid獲取openid

    public static string GetOpenidByFakeid(string fakeid)
    {
        try
        {
            CookieContainer cookie = null;
            string token = null;


            cookie = WeiXinLogin.LoginInfo.LoginCookie;//取得cookie
            token = WeiXinLogin.LoginInfo.Token;//取得token
            string Url = "https://mp.weixin.qq.com/cgi-bin/singlemsgpage?msgid=&source=&count=20&t=wxm-singlechat&fromfakeid=" + fakeid + "&token=" + token + "&lang=zh_CN";
            HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(Url);
            webRequest2.CookieContainer = cookie;
            webRequest2.ContentType = "text/html; charset=UTF-8";
            webRequest2.Method = "GET";
            webRequest2.UserAgent = "Mozilla/5.0 (Windows NT 5.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1";
            webRequest2.ContentType = "application/x-www-form-urlencoded";
            HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();
            StreamReader sr2 = new StreamReader(response2.GetResponseStream(), Encoding.UTF8);
            string text2 = sr2.ReadToEnd();
            HtmlDocument doc = new HtmlDocument();
            doc.LoadHtml(text2);
            var str = doc.GetElementbyId("json-msgList").InnerHtml;
            JArray messages = JArray.Parse(str);
            foreach (var message in messages)
            {
                string strContent = HttpUtility.HtmlDecode(message["content"].ToString());
                Regex reg = new Regex(@"(?is)<a[^>]*?href=(['""\s]?)(?<href>[^'""\s]*)\1[^>]*?>");
                MatchCollection match = reg.Matches(strContent);
                var href = "";
                foreach (Match m in match)
                {
                    href = m.Groups["href"].Value;
                }

                var openid = GetUrlParamValue(href, "openid");
                if (!string.IsNullOrEmpty(openid))
                 return openid;

            }
            return "";
        }
        catch (Exception ex)
        {
            return "";
        }
  
    }

 

由於之前有建立openid與usercode的關系，所以可以根據usercode找到openid，又可以根據openid找到fakeid。使用下面代碼進行推送：

    public static bool SendMessage(string Message, string fakeid)
    {
        bool result = false;
        CookieContainer cookie = null;
        string token = null;
        cookie = WeiXinLogin.LoginInfo.LoginCookie;//取得cookie
        token =  WeiXinLogin.LoginInfo.Token;//取得token

        string strMsg = System.Web.HttpUtility.UrlEncode(Message);  //對傳遞過來的信息進行url編碼
        string padate = "type=1&content=" + strMsg + "&error=false&tofakeid=" + fakeid + "&token=" + token + "&ajax=1";
        string url = "https://mp.weixin.qq.com/cgi-bin/singlesend?t=ajax-response&lang=zh_CN";

        byte[] byteArray = Encoding.UTF8.GetBytes(padate); // 轉化

        HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(url);

        webRequest2.CookieContainer = cookie; //登錄時得到的緩存

        webRequest2.Referer = "https://mp.weixin.qq.com/cgi-bin/singlemsgpage?token=" + token + "&fromfakeid=" + fakeid + "&msgid=&source=&count=20&t=wxm-singlechat&lang=zh_CN";

        webRequest2.Method = "POST";

        webRequest2.UserAgent = "Mozilla/5.0 (Windows NT 5.1; rv:2.0.1) Gecko/20100101 Firefox/4.0.1";

        webRequest2.ContentType = "application/x-www-form-urlencoded";

        webRequest2.ContentLength = byteArray.Length;

        Stream newStream = webRequest2.GetRequestStream();

        // Send the data.            
        newStream.Write(byteArray, 0, byteArray.Length);    //寫入參數    

        newStream.Close();

        HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();

        StreamReader sr2 = new StreamReader(response2.GetResponseStream(), Encoding.Default);

        string text2 = sr2.ReadToEnd();
        if (text2.Contains("ok"))
        {
            result = true;
        }
        return result;
    }

　　

可以寫一個長期運行的windows服務用於建立fakeid和openid的關系，這里不再詳訴。