婚慶現場或年會上有在大屏上一直滾動的視訊，來賓關注公眾號後就可以直接傳送留言上牆了，看起來貌似好好玩的樣子
彈幕一般利用websocket和後臺server建立連線然後傳送/接收資料，這裡使用H5來做前臺頁面，只是一個demo沒有做過多的美化和優化，特別是server端程式碼，一旦資訊多了會撐爆記憶體，如果需要在實際中使用還需進一步處理。
前臺展示主要用到了websocket，基本上看原始碼就能明白，核心程式碼如下：

<script>
    //WebSocket
    var wsServer = 'ws://172.17.154.228:7181';
    var websocket=
 
 new WebSocket(wsServer);

    websocket.onopen = function (evt) {
        console.log("Connected to WebSocket server.");
        /*websocket.send("gaga");*/
        //連上之後就開啟彈幕
        $('#danmu').danmu('danmuResume');
    };

    websocket.onclose = function (evt) {
        console.log("Disconnected")
 
;
    };

    websocket.onmessage = function (evt) {
        console.log('Retrieved data from server: ' + evt.data);
        var time = $('#danmu').data("nowTime")+1;
        var text_obj = evt.data.indexOf("time") == -1 ? evt.data + ',"time":' + time + '}' : evt.data;//獲取加上當前時間
        console.log(text_obj)
 
;
        var new_obj = eval('(' + text_obj + ')');
        $('#danmu').danmu("addDanmu",new_obj);//新增彈幕
    };

    websocket.onerror = function (evt, e) {
            console.log('Error occured: ' + evt.data);
    };



  //初始化
  $("#danmu").danmu({
    left:0,
    top:0,
    height:"100%",
    width:"100%",
    speed:20000,
    opacity:1,
    font_size_small:16,
    font_size_big:24,
    top_botton_danmu_time:6000
  });
    //一個定時器，監視彈幕時間並更新到頁面上
  function timedCount(){
    $("#time").text($('#danmu').data("nowTime"));

    t=setTimeout("timedCount()",50)

  }
  timedCount();


  function starter(){
    $('#danmu').danmu('danmuStart');
  }
  function pauser(){
    $('#danmu').danmu('danmuPause');
  }
  function resumer(){
    $('#danmu').danmu('danmuResume');
  }
  function stoper(){
    $('#danmu').danmu('danmuStop');
  }
  function getime(){
    alert($('#danmu').data("nowTime"));
  }
  function getpaused(){
    alert($('#danmu').data("paused"));
  }

  //傳送彈幕，使用了文件README.md第7節中推薦的方法
  function send(){
    var text = document.getElementById('text').value;
    var color = document.getElementById('color').value;
    var position = document.getElementById('position').value;
    var time = $('#danmu').data("nowTime")+1;
    var size =document.getElementById('text_size').value;
    var text_obj='{ "text":"'+text+'","color":"'+color+'","size":"'+size+'","position":"'+position+'","time":'+time+'}';
    //為了處理簡單，方便後續加time，和isnew，就先醬紫發一半吧。
    //注：time為彈幕出來的時間，isnew為是否加邊框，自己發的彈幕，常理上來說是有邊框的。
    //var text_obj='{ "text":"'+text+'","color":"'+color+'","size":"'+size+'","position":"'+position+'"';
    //利用websocket傳送
    websocket.send(text_obj);
    //清空相應的內容
    document.getElementById('text').value='';
  }
  //調整透明度函式
  function op(){
    var op=document.getElementById('op').value;
    $('#danmu').danmu("setOpacity",op/100);
  }

  //調隱藏 顯示
  function changehide() {
    var op = document.getElementById('op').value;
    op = op / 100;
    if (document.getElementById("ishide").checked) {
      $("#danmu").danmu("setOpacity",1)
    } else {
      $("#danmu").danmu("setOpacity",0)

    }
  }

  //設定彈幕時間
  function settime(){
    var t=document.getElementById("set_time").value;
    t=parseInt(t)
    $('#danmu').danmu("setTime",t);
  }
</script>

在服務端儲存每個進來的連線，然後將接收到的訊息分發出去

server.Start(socket =>
{
    socket.OnOpen = () =>
    {
        Console.WriteLine("Open!");
        foreach(string msg in readBuffer)
        {
            socket.Send(msg);
        }
        allSockets.Add(socket);
    };
    socket.OnClose = () =>
    {
        Console.WriteLine("Close!");
        allSockets.Remove(socket);
        if (allSockets.Count == 0)
        {
            StreamWriter sw = new StreamWriter(recordPath);
            foreach (string msg in readBuffer)
                sw.WriteLine(msg);
            sw.Close();
        }
    };
    socket.OnMessage = message =>
    {
        Console.WriteLine(message);
        readBuffer.Add(message);
        allSockets.ToList().ForEach(s => s.Send(message.Substring(0,message.LastIndexOf(','))));                    
    };
    socket.OnBinary = file => {
        string path = ("D:\\test.txt");
        //建立一個檔案流
        FileStream fs = new FileStream(path, FileMode.Create);
        //將byte陣列寫入檔案中
        fs.Write(file, 0, file.Length);        
        fs.Close();
    };
});


var input = Console.ReadLine();
while (input != "exit")
{
    foreach (var socket in allSockets.ToList())
    {
        socket.Send(input);
    }
    input = Console.ReadLine();
}

附加：原始碼傳送門