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。