ASP.NET 应用中大文件上传研究

HttpApplication application1 = sender as HttpApplication;
HttpWorkerRequest request1 = (HttpWorkerRequest) ((IServiceProvider) HttpContext.Current).GetService(typeof(HttpWorkerRequest));
try
{
　if (application1.Context.Request.ContentType.IndexOf("multipart/form-data") <= -1)
　{
　　return;
　}
　//Check The HasEntityBody
　if (!request1.HasEntityBody())
　{
　　return;
　}
　int num1 = 0;
　TimeSpan span1 = DateTime.Now.Subtract(this.beginTime);

　string text1 = application1.Context.Request.ContentType.ToLower();

　byte[] buffer1 = Encoding.ASCII.GetBytes(("\r\n--" + text1.Substring(text1.IndexOf("boundary=") + 9)).ToCharArray());
　int num2 = Convert.ToInt32(request1.GetKnownRequestHeader(11));
　Progress progress1 = new Progress();

　application1.Context.Items.Add("FileList", new Hashtable());

　byte[] buffer2 = request1.GetPreloadedEntityBody();
　num1 += buffer2.Length;

　string text2 = this.AnalysePreloadedEntityBody(buffer2, "UploadGUID");
　if (text2 != string.Empty)
　{
　　application1.Context.Items.Add("LionSky_UpLoadModule_UploadGUID", text2);
　}
　bool flag1 = true;
　if ((num2 > this.UpLoadFileLength()) && ((0 > span1.TotalHours) || (span1.TotalHours > 3)))
　{
　　flag1 = false;
　}
　if ((0 > span1.TotalHours) || (span1.TotalHours > 3))
　{
　　flag1 = false;
　}
　string text3 = this.AnalysePreloadedEntityBody(buffer2, "UploadFolder");
　ArrayList list1 = new ArrayList();
　RequestStream stream1 = new RequestStream(buffer2, buffer1, null, RequestStream.FileStatus.Close, RequestStream.ReadStatus.NoRead, text3, flag1, application1.Context, string.Empty);
　list1.AddRange(stream1.ReadBody);
　if (text2 != string.Empty)
　{
　　progress1.FileLength = num2;
　　progress1.ReceivedLength = num1;
　　progress1.FileName = stream1.OriginalFileName;
　　progress1.FileCount = ((Hashtable) application1.Context.Items["FileList"]).Count;
　　application1.Application["_UploadGUID_" + text2] = progress1;
　}
　if (!request1.IsEntireEntityBodyIsPreloaded())
　{
　　byte[] buffer4;
　　ArrayList list2;
　　int num3 = 204800;
　　byte[] buffer3 = new byte[num3];
　　while ((num2 - num1) >= num3)
　　{
　　　if (!application1.Context.Response.IsClientConnected)
　　　{
　　　　this.ClearApplication(application1);
　　　}
　　　num3 = request1.ReadEntityBody(buffer3, buffer3.Length);
　　　num1 += num3;
　　　list2 = stream1.ContentBody;
　　　if (list2.Count > 0)
　　　{
　　　　buffer4 = new byte[list2.Count + buffer3.Length];
　　　　list2.CopyTo(buffer4, 0);
　　　　buffer3.CopyTo(buffer4, list2.Count);
　　　　stream1 = new RequestStream(buffer4, buffer1, stream1.FileStream, stream1.FStatus, stream1.RStatus, text3, flag1, application1.Context, stream1.OriginalFileName);
　　　}
　　　else
　　　{
　　　　stream1 = new RequestStream(buffer3, buffer1, stream1.FileStream, stream1.FStatus, stream1.RStatus, text3, flag1, application1.Context, stream1.OriginalFileName);
　　　}
　　　list1.AddRange(stream1.ReadBody);
　　　if (text2 != string.Empty)
　　　{
　　　　progress1.ReceivedLength = num1;
　　　　progress1.FileName = stream1.OriginalFileName;
　　　　progress1.FileCount = ((Hashtable) application1.Context.Items["FileList"]).Count;
　　　　application1.Appl