Click here to Skip to main content
15,867,568 members
Articles / Web Development / ASP.NET

File Download in ASP.NET and Tracking the Status of Success/Failure of Download

Rate me:
Please Sign up or sign in to vote.
4.86/5 (133 votes)
27 Apr 2010CPOL3 min read 239.9K   10.9K   176   48
File download in ASP.NET and tracking the status of success/failure of download

Introduction

This article demonstrates how to provide download of a file in ASP.NET along with tracking its success and failure. It will be useful especially in an e-commerce system that offers downloadable product option. In an e-commerce system, it is very important to keep track of status of download. For a download option, there can be two scenarios:

  1. Complete/success download
  2. Failure download

In an e-commerce system, the user may have a limited number of downloads allowed which is one in most of the cases. If a download is successful, it should update the record which will indicate to the user that he has already downloaded the file or increment the download count by 1. But for failure download, the user should be able to download it again or the download count should remain the same. So this article will help in tracking such status of download.

While working on an e-commerce project, I had a requirement to implement such a functionality where the success/failure of the download can be tracked. After searching for the solution, I found that there is no such article related to a similar problem. Then I came up with this solution after reading an article on transferring file in small packets. I hope this solution will help others struggling with a similar problem.

Background

When the function provided is called on the click of a download button, a similar window as shown below opens asking the user to Open, Save or Cancel.

Download_Track

Clicking Open or Save will result in start of download whereas Cancel will stop/fail the download.

Download_Track2.jpg

A user can Cancel the Download even after Open or Save click, which needs to be tracked.

Using the Code

The code contains the basic logic of File Download in ASP.NET, which will not give end-user any hint of the location of the file. First we create System.IO.FileInfo object providing the complete file path, which will give us the file length. We also create a FileStream object which will be passed to BinaryReader object which in turn will help reading the data into bytes. Then we use the Response object to transfer the data.

C#
//File Path and File Name
string filePath = Server.MapPath("~/ApplicationData/DownloadableProducts");
string _DownloadableProductFileName = "DownloadableProduct_FileName.pdf";

System.IO.FileInfo FileName = new System.IO.FileInfo(filePath + "\\" + 
	_DownloadableProductFileName);
FileStream myFile = new FileStream(filePath + "\\" + 
	_DownloadableProductFileName, FileMode.Open, 
	FileAccess.Read, FileShare.ReadWrite);

//Reads file as binary values
BinaryReader _BinaryReader = new BinaryReader(myFile);

long startBytes = 0;
string lastUpdateTiemStamp = File.GetLastWriteTimeUtc(filePath).ToString("r");
string _EncodedData = HttpUtility.UrlEncode
	(_DownloadableProductFileName, Encoding.UTF8) + lastUpdateTiemStamp; 

//Clear the content of the response
Response.Clear();
Response.Buffer = false;
Response.AddHeader("Accept-Ranges", "bytes");
Response.AppendHeader("ETag", "\"" + _EncodedData +"\"");
Response.AppendHeader("Last-Modified", lastUpdateTiemStamp);

//Set the ContentType
Response.ContentType = "application/octet-stream";

//Add the file name and attachment, 
//which will force the open/cancel/save dialog to show, to the header
Response.AddHeader("Content-Disposition", "attachment;filename="+ FileName.Name);

//Add the file size into the response header
Response.AddHeader("Content-Length", (FileName.Length - startBytes).ToString());
Response.AddHeader("Connection", "Keep-Alive");

//Set the Content Encoding type
Response.ContentEncoding = Encoding.UTF8; 

//Send data
_BinaryReader.BaseStream.Seek(startBytes, SeekOrigin.Begin);

There is no response coming back from the download window whether download is completed or aborted in between, so it becomes more difficult to know the status of download. The basic logic behind tracking the download status is transferring the file into smaller packets(size of packets can be kept as per convenience) and checking whether all the packets have been transferred. If there will be any failure in between the transfer of file, the total number of packets will be compared with the number of packets transferred. This comparison will decide the status (Success/Failure) of download. For a very small file, it is difficult to track failure of download as the number of packets will be very few. So more effective tracking will happen if the file size will be greater than 10 KB.

In the below code, we are getting the total number of packets by dividing the total bytes of data by 1024 to keep the packet size as 1 KB. To send the data packets one by one, we are using for loop. Using Response.BinaryWrite, we are sending the 1024 bytes of data at a time which is read using BinaryReader.

C#
//Dividing the data in 1024 bytes package
int maxCount = (int)Math.Ceiling((FileName.Length - startBytes + 0.0) / 1024); 
C#
//Download in block of 1024 bytes
int i;
for(i=0; i < maxCount && Response.IsClientConnected; i++)
{
    Response.BinaryWrite(_BinaryReader.ReadBytes(1024));
    Respons.Flush(); 
}

Then we compare the number of data packets transferred with the total number of data packets which we calculated by dividing file length by 1024. If both the parameters are equal, that means that file transfer is successful and all the packets got transferred. If number of data packets transferred are less than the total number of data packets, that indicates there is some problem and the transfer was not complete.

C#
//compare packets transferred with total number of packets
if (i < maxCount) return false;
return true;  

Close the Binary reader and File stream in final block.

C#
//Close Binary reader and File stream
_BinaryReader.Close();
myFile.Close(); 

History

  • 27th April, 2010: Initial post

About Proteans Software Solutions

Proteans Software Solutions is an outsourcing company focusing on software product development and business application development on Microsoft Technology Platform. Committed to consistently deliver high-quality software products and services through continual improvement of our knowledge and practices focused on increased customer satisfaction.

License

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


Written By
Software Developer Proteans Software Solutions Pvt. Ltd.
India India
I am working as a software engineer in Proteans Software Solutions.

Comments and Discussions

 
GeneralAwesome work man, I was in need of such solution. Pin
shriti.nisha@gmail.com29-Apr-10 7:49
shriti.nisha@gmail.com29-Apr-10 7:49 
GeneralRe: Awesome work man, I was in need of such solution. Pin
Anil Meharia29-Apr-10 8:09
Anil Meharia29-Apr-10 8:09 
GeneralGreat one Pin
Brij28-Apr-10 19:06
mentorBrij28-Apr-10 19:06 
GeneralGood Article dude Pin
avi5128-Apr-10 1:44
avi5128-Apr-10 1:44 
JokeWorking Hard Pin
pun2et28-Apr-10 0:01
pun2et28-Apr-10 0:01 
Questionwhat about downloadmanagers? Pin
PeaceTiger27-Apr-10 23:28
PeaceTiger27-Apr-10 23:28 
AnswerRe: what about downloadmanagers? Pin
Anil Meharia27-Apr-10 23:33
Anil Meharia27-Apr-10 23:33 
GeneralRe: what about downloadmanagers? Pin
Pete O'Hanlon28-Apr-10 10:19
subeditorPete O'Hanlon28-Apr-10 10:19 
Please, make sure that you dispose of resources like the FileStream. If you wrap it into a using block, that should take care of it.

"WPF has many lovers. It's a veritable porn star!" - Josh Smith

As Braveheart once said, "You can take our freedom but you'll never take our Hobnobs!" - Martin Hughes.


My blog | My articles | MoXAML PowerToys | Onyx



GeneralGood job Anil.. Pin
SureshGubba27-Apr-10 21:08
SureshGubba27-Apr-10 21:08 
GeneralGood one -- Its nice way to keep track the status of download .. User friendly :) Pin
san_vetakari27-Apr-10 20:51
san_vetakari27-Apr-10 20:51 
General[My vote of 1] Question Pin
sasha winston27-Apr-10 5:40
sasha winston27-Apr-10 5:40 
GeneralRe: [My vote of 1] Question Pin
Diamonddrake27-Apr-10 10:26
Diamonddrake27-Apr-10 10:26 
GeneralRe: [My vote of 1] Question Pin
Anil Meharia27-Apr-10 18:30
Anil Meharia27-Apr-10 18:30 
GeneralRe: [My vote of 1] Question Pin
Pete O'Hanlon28-Apr-10 10:18
subeditorPete O'Hanlon28-Apr-10 10:18 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.