C#制作简单的多人在线即时交流聊天室


实现网页版的在线聊天室的方法有很多,在没有来到HTML5之前,常见的有:定时轮询、长连接+长轮询、基于第三方插件(如FLASH的Socket),而如果是HTML5,则比较简单,可以直接使用WebSocket,当然HTML5目前在PC端并没有被所有浏览器支持,所以我的这个聊天室仍是基于长连接+长轮询+原生的JS及AJAX实现的多人在线即时交流聊天室,这个聊天室其实是我上周周末完成的,功能简单,可能有些不足,但可以满足在线即时聊天需求,分享也是给大家提供一个思路,大家可以基于此来实现更好的在线即时聊天工具。

聊天室功能简介:

1。支持多人进入同一个聊天室聊天;

2。进入即离线均会自动生成通知信息显示在聊天室中,这样聊天的人们就知道谁进来了谁离开了;

3。实时显示在线人员表列;

4。无需数据库支持,全部存在内存中,当然有条件的可以采用分布式缓存或加一个数据库来存,这里演示就是用内存来存了。

下面就开始分享我的代码,由于采用原生的JS及AJAX,所以简单易懂,代码分别WEB前端及服务端(有点废话了)

WEB前端源代码如下:(ChatPage.html)

<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title></title>
  <style type="text/css">
    html, body {
      margin: 0px;
      padding: 0px;
      width: 100%;
      height: 100%;
      background-color: #f8f7f7;
      font-family: arial,sans-serif;
    }
 
    #layouttable {
      margin:0px;
      padding:0px;
      width:100%;
      height:100%;
      border:2px solid green;
      border-collapse:collapse;
      min-width:800px;
    }
 
      #layouttable td {
        border: 1px solid green;
      }
 
    .h100p {
      height:100%;
    }
 
    .midtr{height:auto;}
      .midtr tr td {
        height: 100%;
      }
 
    #chatmsgbox, #chatonlinebox {
      background-color:white;
      overflow-x: hidden;
      overflow-y: auto;
      overflow-wrap: break-word;
      height: 100%;
    }
 
    #chatonlinebox {
      background-color:#f5d0a8;
    }
 
    .rc, .sd {
      overflow:hidden;
    }
 
     .rc p {
      float: left;
      color: green;
    }
      .sd p {
        float: right;
        color: orange;
      }
  </style>
 
</head>
<body>
  <table id="layouttable">
    <colgroup>
      <col style="width:auto" />
      <col style="width: 200px;" />
    </colgroup>
    <tr style="height:30px; background-color:lightblue;color:yellow;">
      <td>
        欢迎进入梦在旅途的网页即时在线大众聊天室 - www.zuowenjun.cn:
      </td>
      <td>
        当前在线人员
      </td>
    </tr>
    <tr style="height:auto;" id="midtr">
      <td>
        <div id="chatmsgbox">
        </div>
      </td>
      <td>
        <div id="chatonlinebox">
          <ul id="chatnames"></ul>
        </div>
      </td>
    </tr>
    <tr style="height:50px;">
      <td colspan="2">
        <label for="name">聊天妮称:</label>
        <input type="text" id="name" style="width:80px;" />
        <input type="button" id="btnsavename" value="确认进入" />
        <label for="msg">输入内容:</label>
        <input type="text" id="msg" style="width:400px;" />
        <input type="button" id="btnSend" value="发送消息" disabled="disabled" />
      </td>
    </tr>
  </table>
  <script type="text/javascript">
    var chatName = null;
    var oChatmsgbox, oMsg, oChatnames;
    var ajaxforSend, ajaxforRecv;
 
    //页面加载初始化
    window.onload = function () {
      document.getElementById("btnsavename").onclick = function () {
        this.disabled = true;
        var oName = document.getElementById("name");
        oName.readOnly = true;
        document.getElementById("btnSend").disabled = false;
        //receiveMsg();
        setChatStatus(oName.value,"on");
      }
 
      document.getElementById("btnSend").onclick = function () {
        sendMsg(oMsg.value);
      };
 
      //init
      oChatmsgbox = document.getElementById("chatmsgbox");
      oMsg = document.getElementById("msg");
      oChatnames = document.getElementById("chatnames");
      ajaxforSend = getAjaxObject();
      ajaxforRecv = getAjaxObject();
    }
 
    //离开时提醒
    window.onbeforeunload = function () {
      event.returnValue = "您确定要退出聊天室吗?";
    }
 
    //关闭时离线
    window.onunload = function () {
      setChatStatus(chatName, "off");
    }
 
    //设置聊天状态:在线 OR 离线
    function setChatStatus(name, status) {
      callAjax(getAjaxObject(), "action=" + status + "&name=" + name, function (rs) {
        if (!rs.success) {
          alert(rs.info);
          return;
        }
        if (status == "on") {
          chatName = document.getElementById("name").value;
          setTimeout("receiveMsg()",500);
        }
        loadOnlineChatNames();
      });
    }
 
    //加载在线人员名称列表
    function loadOnlineChatNames(){
      callAjax(getAjaxObject(), "action=onlines", function (rs) {
        var lis = "";
        for(var i=0;i<rs.length;i++)
        {
          lis += "<li>"+ rs[i] +"</li>";
        }
        oChatnames.innerHTML = lis;
      });
    }
 
    //接收消息列表
    function receiveMsg() {
      callAjax(ajaxforRecv, "action=receive&name=" + chatName, function (rs) {
        if (rs.success) {
          showChatMsgs(rs.msgs, "rc");
        }
        setTimeout("receiveMsg()", 500);
      });
    }
    //发送消息
    function sendMsg(msg) {
      callAjax(ajaxforSend, "action=send&name=" + chatName + "&msg=" + escape(msg), function (rs) {
        if (rs.success) {
          showChatMsgs(rs.msgs, "sd");
          oMsg.value = null;
          //alert("发送成功!");
        }
      });
    }
 
    //显示消息
    function showChatMsgs(msgs, cssClass) {
      var loadonline = false;
      for (var i = 0; i < msgs.length; i++) {
        var msg = msgs[i];
        oChatmsgbox.innerHTML += "<div class='" + cssClass + "'><p>[" + msg.name + "] - " + msg.sendtime + " 说:<br/>" + msg.content + "</p></div>";
        if (msg.type == "on" || msg.type == "off")
        {
          loadonline = true;
        }
      }
      if (loadonline)
      {
        loadOnlineChatNames();
      }
    }
 
    //调用AJAX
    function callAjax(ajax, param, callback) {
 
      ajax.open("post", "ChatHandler.ashx", true);
      ajax.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
      ajax.onreadystatechange = function () {
        if (ajax.readyState == 4 && ajax.status == 200) {
          var json = eval("(" + ajax.responseText + ")");
          callback(json);
        }
      };
      ajax.send(param);
    }
 
    //获取AJAX对象(XMLHttpRequest)
    function getAjaxObject() {
      var xmlhttp;
      if (window.XMLHttpRequest) {// code for IE7+, Firefox, Chrome, Opera, Safari
        xmlhttp = new XMLHttpRequest();
      }
      else {// code for IE6, IE5
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
      }
      return xmlhttp;
    }
 
  </script>
</body>
</html>

代码很简单,并都有注释,在此就不作说明了,如果有疑问欢迎在下方评论。

服务端(ChatHandler.ashx) 

<%@ WebHandler Language="C#" Class="ChatHandler" %>
 
using System;
using System.Web;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Web.Script.Serialization;
using System.Threading;
using System.Collections.Concurrent;
 
public class ChatHandler : IHttpHandler
{
 
  private class Msg
  {
    public string name { get; set; }
    public string sendtime { get; set; }
    public string content { get; set; }
    public string readednams { get; set; }
    public int readedCount { get; set; }
    public string type { get; set; }
  }
 
  private static List<Msg> msgs = new List<Msg>();
  private static ReaderWriterLockSlim rwLock = new ReaderWriterLockSlim();
  private static object syncObject = new object(),syncObject1 = new object();
  private static List<string> onLineNames = new List<string>();
 
  public void ProcessRequest(HttpContext context)
  {
    string chatName = context.Request.Form["name"];
    string msg = context.Request.Form["msg"];
    string actionName = context.Request.Form["action"];
    JavaScriptSerializer jsSerializer = new JavaScriptSerializer();
 
    object responseObject = null;
 
    switch (actionName)
    {
      case "receive":
        {
          responseObject = GetNewMessages(chatName);
          break;
        }
      case "send":
        {
          responseObject = SendMessage(chatName, msg, "normal");
          break;
        }
      case "on":
      case "off":
        {
          responseObject = SetChatStatus(chatName, actionName);
          break;
        }
      case "onlines":
        {
          responseObject = onLineNames;
          break;
        }
    }
 
    context.Response.ContentType = "text/json";
    context.Response.Write(jsSerializer.Serialize(responseObject));
 
  }
 
  private object SetChatStatus(string chatName, string status)
  {
    if (status == "on")
    {
      if (onLineNames.Exists(s => s == chatName))
      {
        return new { success = false, info = "该聊天妮称已经存在,请更换一个名称吧!" };
      }
      lock (syncObject1)
      {
        onLineNames.Add(chatName);
      }
      SendMessage(chatName, "大家好,我进入聊天室了!", status);
      return new { success = true, info = string.Empty };
    }
    else
    {
      lock (syncObject1)
      {
        onLineNames.Remove(chatName);
      }
      SendMessage(chatName, "再见,我离开聊天室了!", status);
      return new { success = true, info = string.Empty };
    }
  }
 
  /// <summary>
  /// 获取未读的新消息
  /// </summary>
  /// <param name="chatName"></param>
  /// <returns></returns>
  private object GetNewMessages(string chatName)
  {
    //第一种:循环处理
    while (true)
    {
 
      var newMsgs = msgs.Where(m => m.name != chatName && !(m.readednams ?? "").Contains(chatName)).OrderBy(m => m.sendtime).ToList();
      if (newMsgs != null && newMsgs.Count() > 0)
      {
        lock (syncObject)
        {
          newMsgs.ForEach((m) =>
          {
            m.readednams += chatName + ",";
            m.readedCount++;
          });
          int chatNameCount = onLineNames.Count();
          msgs.RemoveAll(m => m.readedCount >= chatNameCount);
        }
 
        return new { success = true, msgs = newMsgs };
      }
 
      Thread.Sleep(1000);
    }
 
 
    //第二种方法,采用自旋锁
    //List<Msg> newMsgs = null;
    //SpinWait.SpinUntil(() =>
    //{
    //  newMsgs = msgs.Where(m => m.name != chatName && !(m.readednams ?? "").Contains(chatName)).OrderBy(m => m.sendtime).ToList();
    //  return newMsgs.Count() > 0;
    //}, -1);
 
    //rwLock.EnterWriteLock();
    //newMsgs.ForEach(m =>
    //{
    //  m.readednams += chatName + ",";
    //  m.readedCount++;
    //});
    //rwLock.ExitWriteLock();
    //return new { success = true, msgs = newMsgs };
  }
 
  /// <summary>
  ///
  /// </summary>
  /// <param name="chatName"></param>
  /// <param name="msg"></param>
  /// <returns></returns>
  private object SendMessage(string chatName, string msg, string type)
  {
    var newMsg = new Msg() { name = chatName, sendtime = DateTime.Now.ToString("yyyy/MM/dd HH:mm"), content =HttpContext.Current.Server.HtmlEncode(msg), readednams = null, type = type };
    //rwLock.EnterWriteLock();
    lock (syncObject)
    {
      msgs.Add(newMsg);
    }
    //rwLock.ExitWriteLock();
    return new { success = true, msgs = new[] { newMsg } };
  }
 
 
 
  public bool IsReusable
  {
    get
    {
      return false;
    }
  }
 
}

代码也相对简单,实现原理主要是:

1。聊天消息:循环获取未读的消息,在取出读的消息同时,将其标识为已读,全部已读的消息则删除;--我这里采用了两种方法,第二种方法被注释掉了,大家可以取消注释试试,也是不错的,比第一种更直观,建议使用;

2。发送消息:实例化一个消息实例并加入到聊天消息集合中;

3。状态切换:上线则加入到在线人员集合中,并生成一条上线消息放入到聊天消息集合中,离线则从在线人员集合中移除该人员信息,并生成一条离线消息放入聊天消息集合中;

注意事项,由于采用了全局静态集合,所以线程同步比较重要。

最终的实现效果展示如下:

 张三:

李四:

小美:

如果觉得不错的话,给个推荐吧,你的支持是推动我不断前进的动力及写作的源泉,我一直坚持:知识在于分享,分享的同时自己也在成长,希望与大家共同成长,谢谢!


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