File size on client side

vincentvdm · August 25th, 2003, 02:18 PM

Hi all,
I'm looking for a solution for the following problem.

A customer logs in to the webserver and see a list with requested file where he payed for. Once the download was sucesfull he cannot download the file a 2th time.

Any idea how to solve this practical ?

Thanks,
Vincent

Imar · August 25th, 2003, 03:16 PM

Hi there,

Can you please not double (or triple or quadra) post your messages? Posting them in one forum usually gives it enough exposure.

Secondly, is the subject incorrect, or the question? They don't seem to match.

Anyway, the easiest way to do this is to use a database. Give each customer a unique idea. As soon as they log in, store this name somewhere (cookie, session, whatever). Before you display the list with files, check whether they have already download the file before. If they have, block the access.

Now, to prevent users from directly requesting the same file again, without going through your file list page, here's the trick:

1. Don't allow direct files; that is, don't store files under your wwwroot folder, but under c:\Documents for example.
2. Provide a general download page (download.asp for example) that takes the ID of the download.
3. In download.asp, implement the following pseudo code:

Code:

If ID is valid
  If Customer has downloaded file before
     Response.Write ("Sorry")
  Else
     Get file from file system and stream it to the browser
  End If
End If

Check here or here for more info on how to push the file to the client.

HtH,

Imar

---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.

vincentvdm · August 26th, 2003, 01:26 PM

Hi Imar and all others,

the problem is not the download but the confirmation that the download has been done succesfull or not!

Thanks,
Vincent

Imar · August 26th, 2003, 02:27 PM

Hi Vincent,

I posted an answer about that here. Would that help?

In short, once the first line after BinaryWrite executes, the download is complete. Wouldn't it be possible to do a Response.Clear and then redirect the user to a confirmation page? Haven't checked it, and doubt that it works (the HTTP headers already being sent, etc). but it might be worth trying....

Imar

---------------------------------------
Imar Spaanjaars
Everyone is unique, except for me.