HTML5 WebSocket实例（三）-文件上传处理

public void ProcessRequest(HttpContext context)
{
//处理WebSocket 请求
context.AcceptWebSocketRequest(DoWork);
}
/// <summary>
/// 委托处理函数定义
/// </summary>
/// <param name="context">当前WebSocket上下文</param>
/// <returns></returns>
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<byte> buffer = new ArraySegment<byte>(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<byte>(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<byte>(Encoding.UTF8.GetBytes(curLength.ToString()));
await socket.SendAsync(buffer, WebSocketMessageType.Text, true, CancellationToken.None);
}
}
else { break; }
}
}
/// <summary>
/// 追加二进制数据到文件
/// </summary>
public string SaveFile(string file, ArraySegment<byte> 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;
}
}

<div class="container">
<div class="panel panel-default">
<div class="panel-heading">分段读取文件：</div>
<div class="panel-body">
<input type="file" id="file" /><br />
<input type="button" value="中止" onclick="stop();" />∅
<input type="button" value="继续" onclick="containue();" />
<progress id="progressOne" style="width:400px;" max="100" value="0"></progress>
<blockquote id="Status" style="word-break:break-all;"></blockquote>
</div>
</div>
</div>

/*
* 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：<a target=_blank href="http://www.cnblogs.com/tianma3798/p/5852475.html" target="_blank">点击查看</a>)
*/
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 < total) {
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();