How to deliver big files in ASP.NET Response?

Question

I am not looking for any alternative of streaming file contents from database, indeed I am looking for root of the problem, this was running file till IIS

Answer 1

When you have set the content length with the bufferOutput to false then the possible reason of the fails is because IIS try to gzip the file you send, and by set the Content-Length IIS can not change it back to the compressed one, and the errors starts (*).

So keep the BufferOutput to false, and second disable the gzip from iis for the files you send - or disable the iis gzip for all files and you handle the gzip part programmatically, keeping out of gzip the files you send.

Some similar questions for the same reason: ASP.NET site sometimes freezing up and/or showing odd text at top of the page while loading, on load balanced servers

HTTP Compression: Some external scripts/CSS not decompressing properly some of the time

(*) why not change it again ? because from the moment you set a header you can not take it back, except if you have enable this option on IIS and take care that the header have not all ready send to the browser.

Follow up

If not gziped, the next thing it came to my mind is that the file is sent and for some reason the connection got delayed, and got a timeout and closed. So you get the "Remote Host Closed The Connection".

This can be solved depending on the cause:

1. Client really closed the connection
2. The timeout is from the page itself, if you use handler (again, probably, the message must be "Page Timed Out" ).
3. The timeout is coming from the idle waiting, the page take more than the execution time, gets a timeout and close the connection. Maybe in this case the message was the Page Timed Out.
4. The pool make a recycle the moment you send the file. Disable all pool recycles! This is the most possible cases that I can think of right now.

If it is coming from the IIS, go to the web site properties and make sure you set the biggest "Connection Timeout", and "Enable HTTP Keep-Alives".

The page timeout by changing the web.config (you can change it programmatically only for one specific page)

Also have a look at : http://weblogs.asp.net/aghausman/archive/2009/02/20/prevent-request-timeout-in-asp-net.aspx

Session lock

One more thing that you need to examine is to not use session on the handler that you use to send the file, because the session locks the action until finish out and if a user take longer time to download a file, a second one may get time out.

some relative:

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Replacing ASP.Net's session entirely

Response.WriteFile function fails and gives 504 gateway time-out