IIS Compression Enabled, downloads fail

Hi, I have enabled HTTP compression in IIS6 and set the compression
level to 9 and it works a treat!! My site has sped up by 55%!!!

One problem though. It is a ASP.NET application that created dynamic
reports etc etc which a client can donwload then. We use the
conventional way of popping up a form called frmDownload.aspx which
will receive the memstream and binarywrite it out. This has always
worked until now.

Now what we get is the following. It still pops the window up and you
get the download file dialog, but it wants to download frmDownload.aspx
and even if you say yes, it comes back with an error saying internet
explorer cant donwload the document and it contains no data. As soon as
we disable compression, it works again.

Any ideas please?

Thank you,
Ryk

David
Mon Dec 12 17:54:33 CST 2005

Make sure that frmDownload.aspx sets the correct Content-Type for the
resource being sent. IE does some content-sniffing and extension matching,
and you may be confusing it.

By default, ASPX pages "claim" that its content is text/html, and if you
send a binary stream it is definitely wrong. Add to that compression
encoding and IE's content-sniffing, and something usually goes awry in
there.

It all starts when the user does not set the Content-Type correctly because
that is when all the other "automatic" corrections kick in.

--
//David
IIS
http://blogs.msdn.com/David.Wang
This posting is provided "AS IS" with no warranties, and confers no rights.
//
"Rykie" <rykneethling@gmail.com> wrote in message
news:1134430209.637971.291290@g43g2000cwa.googlegroups.com...
Hi, I have enabled HTTP compression in IIS6 and set the compression
level to 9 and it works a treat!! My site has sped up by 55%!!!

One problem though. It is a ASP.NET application that created dynamic
reports etc etc which a client can donwload then. We use the
conventional way of popping up a form called frmDownload.aspx which
will receive the memstream and binarywrite it out. This has always
worked until now.

Now what we get is the following. It still pops the window up and you
get the download file dialog, but it wants to download frmDownload.aspx
and even if you say yes, it comes back with an error saying internet
explorer cant donwload the document and it contains no data. As soon as
we disable compression, it works again.

Any ideas please?

Thank you,
Ryk

David
Tue Dec 13 01:40:28 CST 2005

Sounds like the problem is still with client-side interpretation of the
response generated by your ASPX page.

I would use Network Monitor or Ethereal to capture the output sent by your
ASPX page and make sure it is correct.

I really cannot comment on client-side behavior. I would only recommend that
you verify that you server-side code sends the correct HTTP response... at
which point you can go to a support group for the client and continue your
questions there.

--
//David
IIS
http://blogs.msdn.com/David.Wang
This posting is provided "AS IS" with no warranties, and confers no rights.
//
"Rykie" <rykneethling@gmail.com> wrote in message
news:1134442554.804165.196350@f14g2000cwb.googlegroups.com...
David,

Thank you for your reply.

Well, I checked the code and I do set the content type everytime. Funny
thing is that when I use http it works, but the moment I use SSL
(https) it fails.

Any ideas?

Ryk

Rykie
Mon Dec 12 21:00:34 CST 2005

The code:

Response.ContentType = Session.Item("ContentType")
Response.AddHeader("Content-Disposition",
Session.Item("Content-Disposition"))

where the Session.Item("ContentType") = "application/pdf"
and Session.Item("Content-Disposition")) = "filename=whatever.pdf"

Ryk

Rykie
Mon Dec 12 20:55:54 CST 2005

David,

Thank you for your reply.

Well, I checked the code and I do set the content type everytime. Funny
thing is that when I use http it works, but the moment I use SSL
(https) it fails.

Any ideas?

Ryk

greg
Wed Dec 14 01:38:05 CST 2005

I had a problem like this when using http compression.
Solved it by turning Compression off on the file that gets called for
download (ie your aspx file) in the metabase.
DoDynamicCompression

http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/d85ae418-e96e-4da1-aaee-5da1dd3e96d8.mspx


"David Wang [Msft]" <someone@online.microsoft.com> wrote in message
news:ew0Hhj7$FHA.1312@TK2MSFTNGP09.phx.gbl...
> Sounds like the problem is still with client-side interpretation of the
> response generated by your ASPX page.
>
> I would use Network Monitor or Ethereal to capture the output sent by your
> ASPX page and make sure it is correct.
>
> I really cannot comment on client-side behavior. I would only recommend
> that
> you verify that you server-side code sends the correct HTTP response... at
> which point you can go to a support group for the client and continue your
> questions there.
>
> --
> //David
> IIS
> http://blogs.msdn.com/David.Wang
> This posting is provided "AS IS" with no warranties, and confers no
> rights.
> //
> "Rykie" <rykneethling@gmail.com> wrote in message
> news:1134442554.804165.196350@f14g2000cwb.googlegroups.com...
> David,
>
> Thank you for your reply.
>
> Well, I checked the code and I do set the content type everytime. Funny
> thing is that when I use http it works, but the moment I use SSL
> (https) it fails.
>
> Any ideas?
>
> Ryk
>
>