【转】让asp.net默认的上传组件支持进度条反映
对于web下的上传，实际上更多的时候不用上传太大东西，asp.net默认的上传组件足够用了，美中不足就是没有上传进度反映，所以现在要做的就是在asp.net默认的上传基础上加上进度反映。
关于web上传的原理，曾在以前有深入分析过《asp无组件上传进度条解决方案》《Asp无组件上传带进度条(续) 》，并有写过asp版的无组件上传进度条，在这里就不多赘述。相信很多人都看过思归发的《用ASP.NET上传大文件》，解决的方法是利用隐含的HttpWorkerRequest，用它的GetPreloadedEntityBody 和 ReadEntityBody方法从IIS为ASP.NET建立的pipe里分块读取数据，对于每块分块进行分析并存储为临时文件，相对比较复杂。
要实现进度条的实时反映，核心的技术就是对上传的数据进行“分块”读取，在读取每块数据时记录当前已上传的块数，根据分块的大小，即可知道已上传的大小，根据总大小，即可知道当前上传的进度。具体的技术还是利用隐含的HttpWorkerRequest，用它的GetPreloadedEntityBody 和 ReadEntityBody方法从IIS为ASP.NET建立的pipe里分块读取数据，只不过仅仅是分块和记录已上传块数而已，用不着对已上传的数据进行分析和处理，因为这部分复杂的工作已经由asp.net的上传组件给我们做了。
根据上面所述的原理，具体代码相对很简单，我写了一个例子，用一个专门的进度显示页面(Progress.aspx)，通过定时刷新(XmlHttp, FF支持)来获取当前上传的进度信息，并实时反映到上传页面上。
代码下载（解压后给web目录设置虚拟目录为“Upload”即可），其中进度条我是用脚本来实现的，单独的进度条脚本代码：
http://www.webuc.net/myproject/progressbar/progressinfo.htm
http://www.webuc.net/myproject/progressbar/progressbar.rar
using System;
using System.Collections;
using System.Collections.Specialized;
using System.Globalization;
using System.IO;
using System.Text;
using System.Web;
using System.Reflection;
namespace Openlab.Web.Upload
{
/// <summary>
/// 给asp.net默认的上传组件加上进度条反映
/// </summary>
/// <Author>宝玉 (http://www.webuc.net)</Author>
/// <Links>
/// http://www.cnforums.net
/// http://www.communtiyserver.cn
/// http://blog.joycode.com
/// </Links>
public class HttpUploadModule: IHttpModule
{
public HttpUploadModule()
{
}
public void Init(HttpApplication application)
{
application.BeginRequest += new EventHandler(this.Application_BeginRequest);
application.EndRequest += new EventHandler(this.Application_EndRequest);
application.Error += new EventHandler(this.Application_Error);
}
public void Dispose()
{
}
private void Application_BeginRequest(Object sender, EventArgs e)
{
HttpApplication app = sender as HttpApplication;
HttpWorkerRequest request = GetWorkerRequest(app.Context);
Encoding encoding = app.Context.Request.ContentEncoding;
int bytesRead = 0; // 已读数据大小
int read; // 当前读取的块的大小
int count = 8192; // 分块大小
byte[] buffer; // 保存所有上传的数据
string uploadId; // 唯一标志当前上传的ID
Progress progress; // 记录当前上传的进度信息
if (request != null)
{
// 返回 HTTP 请求正文已被读取的部分。
//
byte[] tempBuff = request.GetPreloadedEntityBody();
// 如果是附件上传
//
if (
tempBuff != null
&& IsUploadRequest(app.Request)
)
{
// 获取上传大小
//
long length = long.Parse(request.GetKnownRequestHeader(HttpWorkerRequest.HeaderContentLength));
// 当前上传的ID，用来唯一标志当前的上传
// 用此UploadID，可以通过其他页面获取当前上传的进度
//
uploadId = app.Context.Request.QueryString["UploadID"];
// 开始记录当前上传状态
//
progress = new Progress(length, uploadId);
progress.SetState(UploadState.ReceivingData);
buffer = new byte[length];
count = tempBuff.Length; // 分块大小
// 将已上传数据复制过去
//
Buffer.BlockCopy(tempBuff, 0, buffer, bytesRead, count);
// 开始记录已上传大小
//
bytesRead = tempBuff.Length;
progress.SetBytesRead(bytesRead);
SetProgress(uploadId, progress, app.Application);
// 循环分块读取，直到所有数据读取结束
//
while (request.IsClientConnected() &&
!request.IsEntireEntityBodyIsPreloaded() &&
bytesRead < length
)
{
// 如果最后一块大小小于分块大小，则重新分块
//
if (bytesRead + count > length)
{
count = (int)(length - bytesRead);
tempBuff = new byte[count];
}
// 分块读取
//
read = request.ReadEntityBody(tempBuff, count);
// 复制已读数据块
//
Buffer.BlockCopy(tempBuff, 0, buffer, bytesRead, read);
// 记录已上传大小
//
bytesRead += read;
progress.SetBytesRead(bytesRead);
SetProgress(uploadId, progress, app.Application);
}
if (
request.IsClientConnected() &&
!request.IsEntireEntityBodyIsPreloaded()
)
{
// 传入已上传完的数据
//
InjectTextParts(request, buffer);
// 表示上传已结束
//
progress.SetBytesRead(bytesRead);
progress.SetState(UploadState.Complete);
SetProgress(uploadId, progress, app.Application);
}
}
}
}
/// <summary>
/// 结束请求后移除进度信息
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Application_EndRequest(Object sender, EventArgs e)
{
HttpApplication app = sender as HttpApplication;
if (IsUploadRequest(app.Request))
{
SetUploadState(app, UploadState.Complete);
RemoveFrom(app);
}
}
/// <summary>
/// 如果出错了设置进度信息中状态为“Error”
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void Application_Error(Object sender, EventArgs e)
{
HttpApplication app = sender as HttpApplication;
if (IsUploadRequest(app.Request))
{
SetUploadState(app, UploadState.Error);
}
}
/// <summary>
/// 设置当前上传进度信息的状态
/// </summary>
/// <param name="app"></param>
/// <param name="state"></param>
void SetUploadState(HttpApplication app, UploadState state)
{
string uploadId = app.Request.QueryString["UploadID"];
if (uploadId != null && uploadId.Length > 0)
{
Progress progress = GetProgress(uploadId, app.Application);
if (progress != null)
{
progress.SetState(state);
SetProgress(uploadId, progress, app.Application);
}
}
}
/// <summary>
/// 设置当前上传的进度信息
/// 根据UploadID记录在Application中
/// </summary>
/// <param name="uploadId"></param>
/// <param name="progress"></param>
/// <param name="application"></param>
void SetProgress(string uploadId, Progress progress, HttpApplicationState application)
{
if (uploadId == null || uploadId == string.Empty || progress == null)
return;
application.Lock();
application["OpenlabUpload_" + uploadId] = progress;
application.UnLock();
}
/// <summary>
/// 从Application中移出进度信息
/// </summary>
/// <param name="app"></param>
void RemoveFrom(HttpApplication app)
{
string uploadId = app.Request.QueryString["UploadID"];
HttpApplicationState application = app.Application;
if (uploadId != null && uploadId.Length > 0)
{
application.Remove("OpenlabUpload_" + uploadId);
}
}
/// <summary>
/// 根据UploadID获取上传进度信息
/// </summary>
/// <param name="uploadId"></param>
/// <param name="application"></param>
/// <returns></returns>
public static Progress GetProgress(string uploadId, HttpApplicationState application)
{
Progress progress = application["OpenlabUpload_" + uploadId] as Progress;
return progress;
}
HttpWorkerRequest GetWorkerRequest(HttpContext context)
{
IServiceProvider provider = (IServiceProvider)HttpContext.Current;
return (HttpWorkerRequest)provider.GetService(typeof(HttpWorkerRequest));
}
/// <summary>
/// 传入已上传完的数据
/// </summary>
/// <param name="request"></param>
/// <param name="textParts"></param>
void InjectTextParts(HttpWorkerRequest request, byte[] textParts)
{
BindingFlags bindingFlags = BindingFlags.Instance | BindingFlags.NonPublic;
Type type = request.GetType();
while ((type != null) && (type.FullName != "System.Web.Hosting.ISAPIWorkerRequest"))
{
type = type.BaseType;
}
if (type != null)
{
type.GetField("_contentAvailLength", bindingFlags).SetValue(request, textParts.Length);
type.GetField("_contentTotalLength", bindingFlags).SetValue(request, textParts.Length);
type.GetField("_preloadedContent", bindingFlags).SetValue(request, textParts);
type.GetField("_preloadedContentRead", bindingFlags).SetValue(request, true);
}
}
private static bool StringStartsWithAnotherIgnoreCase(string s1, string s2)
{
return (string.Compare(s1, 0, s2, 0, s2.Length, true, CultureInfo.InvariantCulture) == 0);
}
/// <summary>
/// 是否为附件上传
/// 判断的根据是ContentType中有无multipart/form-data
/// </summary>
/// <param name="request"></param>
/// <returns></returns>
bool IsUploadRequest(HttpRequest request)
{
return StringStartsWithAnotherIgnoreCase(request.ContentType, "multipart/form-data");
}
}
}
posted on 2008-07-12 04:08 LeeXiaoLiang 阅读(533) 评论(0) 编辑 收藏 举报
