How to inetrnet conection disconnet then pause file upload

Here is a solution I had found in MSDN but not able to get the correct link now.

Create a class called "Downloader.cs" with the following content:

using System;
using System.IO;
using System.Text;
using System.Web;
namespace CSASPNETResumeDownload
{
public class Downloader
{
public static void DownloadFile(HttpContext httpContext, string filePath)
{
if (!IsFileExists(filePath))
{
httpContext.Response.StatusCode = 404;
return;
}
FileInfo fileInfo = new FileInfo(filePath);
if (fileInfo.Length > Int32.MaxValue)
{
httpContext.Response.StatusCode = 413;
return;
}
// Get the response header information by the http request.
HttpResponseHeader responseHeader = GetResponseHeader(httpContext.Request, fileInfo);
if (responseHeader == null)
{
return;
}
FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
try
{
SendDownloadFile(httpContext.Response, responseHeader, fileStream);
}
catch (HttpException ex)
{
httpContext.Response.StatusCode = ex.GetHttpCode();
}
finally
{
fileStream.Close();
}
}
///
/// Check whether the file exists.
///
///
///
private static bool IsFileExists(string filePath)
{
bool fileExists = false;
if (!string.IsNullOrEmpty(filePath))
{
if (File.Exists(filePath))
{
fileExists = true;
}
}
return fileExists;
}
///
/// Get the response header by the http request.
///
///
///
///
private static HttpResponseHeader GetResponseHeader(HttpRequest httpRequest, FileInfo fileInfo)
{
if (httpRequest == null)
{
return null;
}
if (fileInfo == null)
{
return null;
}
long startPosition = 0;
string contentRange = "";
string fileName = fileInfo.Name;
long fileLength = fileInfo.Length;
string lastUpdateTimeStr = fileInfo.LastWriteTimeUtc.ToString();
string eTag = HttpUtility.UrlEncode(fileName, Encoding.UTF8) + " " + lastUpdateTimeStr;
string contentDisposition = "attachment;filename=" + HttpUtility.UrlEncode(fileName, Encoding.UTF8).Replace("+", "%20");
if (httpRequest.Headers["Range"] != null)
{
string[] range = httpRequest.Headers["Range"].Split(new char[] { '=', '-' });
startPosition = Convert.ToInt64(range[1]);
if (startPosition < 0 || startPosition >= fileLength)
{
return null;
}
}
if (httpRequest.Headers["If-Range"] != null)
{
if (httpRequest.Headers["If-Range"].Replace("\"", "") != eTag)
{
startPosition = 0;
}
}
string contentLength = (fileLength - startPosition).ToString();
if (startPosition > 0)
{
contentRange = string.Format(" bytes {0}-{1}/{2}", startPosition, fileLength - 1, fileLength);
}
HttpResponseHeader responseHeader = new HttpResponseHeader();
responseHeader.AcceptRanges = "bytes";
responseHeader.Connection = "Keep-Alive";
responseHeader.ContentDisposition = contentDisposition;
responseHeader.ContentEncoding = Encoding.UTF8;
responseHeader.ContentLength = contentLength;
responseHeader.ContentRange = contentRange;
responseHeader.ContentType = "application/octet-stream";
responseHeader.Etag = eTag;
responseHeader.LastModified = lastUpdateTimeStr;
return responseHeader;
}
///
/// Send the download file to the client.
///
///
///
///
private static void SendDownloadFile(HttpResponse httpResponse, HttpResponseHeader responseHeader, Stream fileStream)
{
if (httpResponse == null || responseHeader == null)
{
return;
}
if (!string.IsNullOrEmpty(responseHeader.ContentRange))
{
httpResponse.StatusCode = 206;
// Set the start position of the reading files.
string[] range = responseHeader.ContentRange.Split(new char[] { ' ','=', '-' });
fileStream.Position = Convert.ToInt64(range[2]);
}
httpResponse.Clear();
httpResponse.Buffer = false;
httpResponse.AppendHeader("Accept-Ranges", responseHeader.AcceptRanges);
httpResponse.AppendHeader("Connection", responseHeader.Connection);
httpResponse.AppendHeader("Content-Disposition", responseHeader.ContentDisposition);
httpResponse.ContentEncoding = responseHeader.ContentEncoding;
httpResponse.AppendHeader("Content-Length", responseHeader.ContentLength);
if (!string.IsNullOrEmpty(responseHeader.ContentRange))
{
httpResponse.AppendHeader("Content-Range", responseHeader.ContentRange);
}
httpResponse.ContentType = responseHeader.ContentType;
httpResponse.AppendHeader("Etag", "\"" + responseHeader.Etag + "\"");
httpResponse.AppendHeader("Last-Modified", responseHeader.LastModified);
Byte[] buffer = new Byte[10240];
long fileLength = Convert.ToInt64(responseHeader.ContentLength);
// Send file to client.
while (fileLength > 0)
{
if (httpResponse.IsClientConnected)
{
int length = fileStream.Read(buffer, 0, 10240);
httpResponse.OutputStream.Write(buffer, 0, length);
httpResponse.Flush();
fileLength = fileLength - length;
}
else
{
fileLength = -1;
}
}
}
}
///
/// Respresent the HttpResponse header information.
///
class HttpResponseHeader
{
public string AcceptRanges { get; set;}
public string Connection { get; set; }
public string ContentDisposition { get; set; }
public Encoding ContentEncoding { get; set; }
public string ContentLength { get; set; }
public string ContentRange { get; set; }
public string ContentType { get; set; }
public string Etag { get; set; }
public string LastModified { get; set; }
}
}

and then replace following content in "DownloadHttpHandler.ashx.cs file

using System;
using System.Configuration;
using System.Web;
namespace CSASPNETResumeDownload
{
public class DownloadHttpHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
string filePath = ConfigurationManager.AppSettings["FilePath"];
Downloader.DownloadFile(context, filePath);
}
public bool IsReusable
{
get { return false; }
}
}
}

See if it still works, else let me know.

1 Reply

Know the answer? Post it — somebody with the same question will find it here.

Suvendu Shekhar Giri6y ago
Here is a solution I had found in MSDN but not able to get the correct link now.

Create a class called "Downloader.cs" with the following content:
using System;
using System.IO;
using System.Text;
using System.Web;

namespace CSASPNETResumeDownload
{
    public class Downloader
    {
        public static void DownloadFile(HttpContext httpContext, string filePath)
        {
            if (!IsFileExists(filePath))
            {
                httpContext.Response.StatusCode = 404;
                return;
            }

            FileInfo fileInfo = new FileInfo(filePath);

            if (fileInfo.Length > Int32.MaxValue)
            {
                httpContext.Response.StatusCode = 413;
                return;
            }

            // Get the response header information by the http request.
            HttpResponseHeader responseHeader = GetResponseHeader(httpContext.Request, fileInfo);

            if (responseHeader == null)
            {
                return;
            }

            FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);

            try
            {
                SendDownloadFile(httpContext.Response, responseHeader, fileStream);
            }
            catch (HttpException ex)
            {
                httpContext.Response.StatusCode = ex.GetHttpCode();
            }
            finally
            {
                fileStream.Close();
            }
        }

        ///

        /// Check whether the file exists.
        ///
        ///
        ///
        private static bool IsFileExists(string filePath)
        {
            bool fileExists = false;

            if (!string.IsNullOrEmpty(filePath))
            {
                if (File.Exists(filePath))
                {
                    fileExists = true;
                }
            }

            return fileExists;
        }

        ///

        /// Get the response header by the http request.
        ///
        ///
        ///
        ///
        private static HttpResponseHeader GetResponseHeader(HttpRequest httpRequest, FileInfo fileInfo)
        {
            if (httpRequest == null)
            {
                return null;
            }

            if (fileInfo == null)
            {
                return null;
            }

            long startPosition = 0;
            string contentRange = "";

            string fileName = fileInfo.Name;
            long fileLength = fileInfo.Length;
            string lastUpdateTimeStr = fileInfo.LastWriteTimeUtc.ToString();

            string eTag = HttpUtility.UrlEncode(fileName, Encoding.UTF8) + " " + lastUpdateTimeStr;
            string contentDisposition = "attachment;filename=" + HttpUtility.UrlEncode(fileName, Encoding.UTF8).Replace("+", "%20");

            if (httpRequest.Headers["Range"] != null)
            {
                string[] range = httpRequest.Headers["Range"].Split(new char[] { '=', '-' });
                startPosition = Convert.ToInt64(range[1]);
                if (startPosition < 0 || startPosition >= fileLength)
                {
                    return null;
                }
            }

            if (httpRequest.Headers["If-Range"] != null)
            {
                if (httpRequest.Headers["If-Range"].Replace("\"", "") != eTag)
                {
                    startPosition = 0;
                }
            }

            string contentLength = (fileLength - startPosition).ToString();

            if (startPosition > 0)
            {
                contentRange = string.Format(" bytes {0}-{1}/{2}", startPosition, fileLength - 1, fileLength);
            }

            HttpResponseHeader responseHeader = new HttpResponseHeader();

            responseHeader.AcceptRanges = "bytes";
            responseHeader.Connection = "Keep-Alive";
            responseHeader.ContentDisposition = contentDisposition;
            responseHeader.ContentEncoding = Encoding.UTF8;
            responseHeader.ContentLength = contentLength;
            responseHeader.ContentRange = contentRange;
            responseHeader.ContentType = "application/octet-stream";
            responseHeader.Etag = eTag;
            responseHeader.LastModified = lastUpdateTimeStr;

            return responseHeader;
        }

        ///

        /// Send the download file to the client.
        ///
        ///
        ///
        ///
        private static void SendDownloadFile(HttpResponse httpResponse, HttpResponseHeader responseHeader, Stream fileStream)
        {
            if (httpResponse == null || responseHeader == null)
            {
                return;
            }

            if (!string.IsNullOrEmpty(responseHeader.ContentRange))
            {
                httpResponse.StatusCode = 206;

                // Set the start position of the reading files.
                string[] range = responseHeader.ContentRange.Split(new char[] { ' ','=', '-' });
                fileStream.Position = Convert.ToInt64(range[2]);
            }
            httpResponse.Clear();
            httpResponse.Buffer = false;
            httpResponse.AppendHeader("Accept-Ranges", responseHeader.AcceptRanges);
            httpResponse.AppendHeader("Connection", responseHeader.Connection);
            httpResponse.AppendHeader("Content-Disposition", responseHeader.ContentDisposition);
            httpResponse.ContentEncoding = responseHeader.ContentEncoding;
            httpResponse.AppendHeader("Content-Length", responseHeader.ContentLength);
            if (!string.IsNullOrEmpty(responseHeader.ContentRange))
            {
                httpResponse.AppendHeader("Content-Range", responseHeader.ContentRange);
            }
            httpResponse.ContentType = responseHeader.ContentType;
            httpResponse.AppendHeader("Etag", "\"" + responseHeader.Etag + "\"");
            httpResponse.AppendHeader("Last-Modified", responseHeader.LastModified);

            Byte[] buffer = new Byte[10240];
            long fileLength = Convert.ToInt64(responseHeader.ContentLength);

            // Send file to client.
            while (fileLength > 0)
            {
                if (httpResponse.IsClientConnected)
                {
                    int length = fileStream.Read(buffer, 0, 10240);

                    httpResponse.OutputStream.Write(buffer, 0, length);

                    httpResponse.Flush();

                    fileLength = fileLength - length;
                }
                else
                {
                    fileLength = -1;
                }
            }
        }
    }

    ///

    /// Respresent the HttpResponse header information.
    ///
    class HttpResponseHeader
    {
        public string AcceptRanges { get; set;}
        public string Connection { get; set; }
        public string ContentDisposition { get; set; }
        public Encoding ContentEncoding { get; set; }
        public string ContentLength { get; set; }
        public string ContentRange { get; set; }
        public string ContentType { get; set; }
        public string Etag { get; set; }
        public string LastModified { get; set; }
    }
}
and then replace following content in "DownloadHttpHandler.ashx.cs file
using System;
using System.Configuration;
using System.Web;

namespace CSASPNETResumeDownload
{
    public class DownloadHttpHandler : IHttpHandler
    {
        public void ProcessRequest(HttpContext context)
        {
            string filePath = ConfigurationManager.AppSettings["FilePath"];
            Downloader.DownloadFile(context, filePath);
        }

        public bool IsReusable
        {
            get { return false; }
        }
    }
}
See if it still works, else let me know.