微信公众平台向特定用户推送消息

最近研究微信公众平台，这里整理了一下向特定用户推送消息的思路

一、首先需要将微信的openid与系统用户绑定。

在用户关注公众平台的时候，回复一个链接，要求用户绑定，可以设计如下消息进行回复，（openid最好进行加密处理，后者还需要用这个字段绑定fakeid）。

欢迎关注有问必答平台,<a href='http://myweixin123.duapp.com/bind.html?openid=@openid'>点击此处进行用户绑定</a>! 

在bind.html页面将openid与系统的usercode进行绑定，这个绑定过程非常简单，这里不详叙述。

二、将openid与fakeid进行绑定

微信公众平台是一回一答的模式；但是在微信公众平台后台，可以向特定用户进行消息发送。我们利用这个机制使用代码去模拟这个过程来实现消息推送。

首先需要模拟登录：

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 的摘要说明
/// </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 ";//请求登录的URL
        try
        {
            CookieContainer cc = new CookieContainer();//接收缓存
            byte[] byteArray = Encoding.UTF8.GetBytes(padata); // 转化
            HttpWebRequest webRequest2 = (HttpWebRequest)WebRequest.Create(url);  //新建一个WebRequest对象用来请求或者响应url
            ServicePointManager.CertificatePolicy = new AcceptAllCertificatePolicy(); 

            webRequest2.CookieContainer = cc;                                      //保存cookie  
            webRequest2.Method = "POST";                                          //请求方式是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";       //请求的内容格式为application/x-www-form-urlencoded
            webRequest2.ContentLength = byteArray.Length;
            Stream newStream = webRequest2.GetRequestStream();           //返回用于将数据写入 Internet 资源的 Stream。
            // Send the data.
            newStream.Write(byteArray, 0, byteArray.Length);    //写入参数
            newStream.Close();
            HttpWebResponse response2 = (HttpWebResponse)webRequest2.GetResponse();
            StreamReader sr2 = new StreamReader(response2.GetResponseStream(), Encoding.Default);
            string text2 = sr2.ReadToEnd();

            //此处用到了newtonsoft来序列化
            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>
        /// 登录后得到的令牌
        /// </summary>        
        public static string Token { get; set; }
        /// <summary>
        /// 登录后得到的cookie
        /// </summary>
        public static CookieContainer LoginCookie { get; set; }
        /// <summary>
        /// 创建时间
        /// </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;
        }
    }  
}

获取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

            /*获取用户信息的url，这里有几个参数给大家讲一下，1.token此参数为上面的token 2.pagesize此参数为每一页显示的记录条数

            3.pageid为当前的页数，4.groupid为微信公众平台的用户分组的组id，当然这也是我的猜想不一定正确*/
            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;

            //由于此方法获取过来的信息是一个html网页所以此处使用了正则表达式，注意：（此正则表达式只是获取了fakeid的信息如果想获得一些其他的信息修改此处的正则表达式就可以了。）
            Regex r = new Regex("\"id\"\\:\\d+,\"nick_name\""); //定义一个Regex对象实例
            mc = r.Matches(text2);
            Int32 friendSum = mc.Count;          //好友总数

            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);
        }
    }

根据fakeid获取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 "";
        }
  
    }

 

由于之前有建立openid与usercode的关系，所以可以根据usercode找到openid，又可以根据openid找到fakeid。使用下面代码进行推送：

    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);  //对传递过来的信息进行url编码
        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); // 转化

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

        webRequest2.CookieContainer = cookie; //登录时得到的缓存

        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);    //写入参数    

        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;
    }

　　

可以写一个长期运行的windows服务用于建立fakeid和openid的关系，这里不再详诉。