HTML5WebSocket实例（三）-文件上传处理

一、后台处理：

        public void ProcessRequest(HttpContext context)
        {
            //处理WebSocket 请求
            context.AcceptWebSocketRequest(DoWork);
        }
        /// 

        /// 委托处理函数定义
        /// 

        /// 当前WebSocket上下文
        /// 
        public async Task DoWork(AspNetWebSocketContext context)
        {
            //1.获取当前WebSocket 对象
            WebSocket socket = context.WebSocket;
            string filename = "";
            //2.监视相应
            while (true)
            {
                /*
                 * 此处缓存数组指定读取客户端数据的长度
                 * 如果客户端发送数据超过当前缓存区，则会读取多次
                 */
                ArraySegment buffer = new ArraySegment(new byte[1024 * 256]);
                //接收客户端信息
                CancellationToken token;
                WebSocketReceiveResult result = await socket.ReceiveAsync(buffer, token);
                if (socket.State == WebSocketState.Open)
                {
                    //判断是否已经到了最后
                    int curLength = Math.Min(buffer.Array.Length, result.Count);
                    //判断用户传入的类型进行处理
                    if (result.MessageType == WebSocketMessageType.Text)
                    {
                        string msg = Encoding.UTF8.GetString(buffer.Array, 0, curLength);
                        filename = msg;
                        buffer = new ArraySegment(Encoding.UTF8.GetBytes("接收文件名成功:" + filename));
                        await socket.SendAsync(buffer, WebSocketMessageType.Text, true, CancellationToken.None);
                    }
                    else if (result.MessageType == WebSocketMessageType.Binary)
                    {
                        //创建并保存文件,如果上传成功，返回当前接收到的文件大小
                        string msg = SaveFile(filename, buffer, curLength);
                        buffer = new ArraySegment(Encoding.UTF8.GetBytes(curLength.ToString()));
                        await socket.SendAsync(buffer, WebSocketMessageType.Text, true, CancellationToken.None);
                    }
                }
                else { break; }
            }
        }
        /// 

        /// 追加二进制数据到文件
        /// 

        public string SaveFile(string file, ArraySegment buffer, int Length)
        {
            //去除文件名中的前后空格
            file = file.Trim();
            string fullname = @"F:\Javascript_Solution\H5Solition\UploadWebForm\content\" + file;
            try
            {
                FileStream fs = new FileStream(fullname, FileMode.Append, FileAccess.Write);
                try
                {
                    byte[] result = buffer.ToArray();
                    fs.Write(result, 0, Length);
                }
                finally
                {
                    fs.Close();
                }
                return "保存文件成功";
            }
            catch (Exception ex)
            {
                return ex.Message;
            }
        }

HTML：

    

        
分段读取文件：

        

            

            ∅
            
            
            

        

    

/*
    * 测试WebSocket上传
    * 本地浏览器上传速度测试单个文件，上传速度IE>FF>Google(Google浏览器慢相当多，原因：点击查看)
    */
var fileBox = document.getElementById('file');
var reader = null;  //读取操作对象
var step = 1024 * 256;  //每次读取文件大小 ,字节数
var cuLoaded = 0; //当前已经读取总数
var file = null; //当前读取的文件对象
var enableRead = true;//标识是否可以读取文件
var total = 0;        //记录当前文件总字节数
var startTime = null; //标识开始上传时间
fileBox.Onchange= function () {
    //获取文件对象
    file = this.files[0];
    total = file.size;
    console.info("文件大小：" + file.size);
    if (ws == null) {
        if (window.confirm('建立与服务器链接失败,确定重试链接吗')) {
            createSocket(function () {
                bindReader();
            });
        }
        return;
    }
    bindReader();
}
//绑定reader
function bindReader() {
    cuLoaded = 0;
    startTime = new Date();
    enableRead = true;
    reader = new FileReader();
    //读取一段成功
    reader.Onload= function (e) {
        console.info('读取总数：' + e.loaded);
        if (enableRead == false)
            return false;
        //根据当前缓冲区来控制客户端读取速度
        if (ws.bufferedAmount > step * 10) {
            setTimeout(function () {
                //继续读取
                console.log('--------------》进入等待');
                loadSuccess(e.loaded);
            }, 3);
        } else {
            //继续读取
            loadSuccess(e.loaded);
        }
    }
    //开始读取
    readBlob();
}
//读取文件成功处理
function loadSuccess(loaded) {
    //将分段数据上传到服务器
    var blob = reader.result;
    //使用WebSocket 服务器发送数据
    if (cuLoaded == 0) //发送文件名
        ws.send(file.name);
    ws.send(blob);
    //如果没有读完，继续
    cuLoaded += loaded;
    if (cuLoaded         readBlob();
    } else {
        console.log('总共上传：' + cuLoaded + ',总共用时：' + (new Date().getTime() - startTime.getTime()) / 1000);
    }
    //显示结果进度
    var percent = (cuLoaded / total) * 100;
    document.getElementById('Status').innerText = percent;
    document.getElementById('progressOne').value = percent;
}
//指定开始位置，分块读取文件
function readBlob() {
    //指定开始位置和结束位置读取文件
    var blob = file.slice(cuLoaded, cuLoaded + step);
    reader.readAsArrayBuffer(blob);
}
//中止
function stop() {
    //中止读取操作
    console.info('中止，cuLoaded：' + cuLoaded);
    enableRead = false;
    reader.abort();
}
//继续
function containue() {
    console.info('继续，cuLoaded：' + cuLoaded);
    enableRead = true;
    readBlob();
}
var ws = null;
//创建和服务器的WebSocket 链接
function createSocket(onSuccess) {
    var url = 'ws://localhost:55373/ashx/upload3.ashx';
    ws = new WebSocket(url);
    ws.Onopen= function () {
        console.log('connected成功');
        if (onSuccess)
            onSuccess();
    }
    ws.Onmessage= function (e) {
        var data = e.data;
        if (isNaN(data) == false) {
            //console.log('当前上传成功：' + data);
        } else {
            console.info(data);
        }
    }
    ws.Onclose= function (e) {
        //中止客户端读取
        stop();
        console.log('链接断开');
    }
    ws.Onerror= function (e) {
        //中止客户端读取
        stop();
        console.info(e);
        console.log('传输中发生异常');
    }
}
//页面加载完建立链接
createSocket();

更多实例：

分段上传七：http://www.cnblogs.com/tianma3798/p/5852475.html

分段上传八：http://www.cnblogs.com/tianma3798/p/5852527.html

更多Demo源代码：http://git.oschina.net/tiama3798/HTML5Demo/tree/WebSocket/