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date: Thu, 3 Jul 2008 06:00:01 -0700,
group: microsoft.public.inetserver.asp.general
back
Re: Adodb.Stream - Problem download big files
Juan wrote on Thu, 3 Jul 2008 06:00:01 -0700:
> Hi!
> I want to use ASP to download big files using ADODB.STREAM. It works
> very fine with files smaller than 80 MB.
> On the Webserver I can see that memory allocation and the process w3wp
> is running. After some time (more or less 2 minutes) I get a response
> timeout.
> Here is the code:
> Server.ScriptTimeout = 30000
> Response.Buffer = True
> Response.Clear
> Response.Expires = 0
> Response.ContentType = "Download-File"
> Response.AddHeader "Content-Disposition","attachment; filename=" &
> sfile
> Set oStream = Server.CreateObject("ADODB.Stream")
> oStream.Type = adTypeBinary oStream.Open oStream.LoadFromFile(sfile)
> Response.AddHeader "Content-Length", oStream.Size ' -- Schönheit
> Response.CharSet = "UTF-8"
> For i = 0 To oStream.Size
> i = i + 128000
> Response.BinaryWrite(oStream.Read(128000))
> Response.Flush
> Next
This looks odd - you're looping from 0 to the size of the stream, yet you're
pushing out 128000 bytes at a time. I think you should be using
For i = 0 To oStream.Size Step 128000
Also, in your loop what happens when you reach the end of the stream?
This is how I handle download from one of my applications
Set oStream = Server.CreateObject("ADODB.Stream")
Call oStream.Open()
oStream.Type = 1
call oStream.LoadFromFile(strFilename)
iDownload = 1
If lcase(right(strfilename,4)) = ".pdf" then
Response.ContentType = "application/pdf"
else
Response.ContentType = "application/octet-stream"
end if
Response.AddHeader "Content-Disposition", "filename=" &
strfilename & ";"
Response.Buffer = False
'stream out the file in chunks
Do While Not (oStream.EOS)
Response.BinaryWrite oStream.Read(1024 * 256)
Loop
oStream.Close
Set oStream = Nothing
this reads the file into the stream (just like you already have), sets an
appropriate ContentType (as Anthony points out the one you use is not a
recognised MIME type), turns off buffering, and then writes out the stream
in 256kB chunks until there is nothing left to write to out (using
oStream.EOS to determine if the stream is at the end).
You really do need buffering turned off - it's entirely possible that the
80MB file is going over the defined ASP buffer limit and so you're getting
an ASP error thrown into the data, and that causes what appears to be a
timeout but is actually due to ASP terminating the script because it has
errored. So far with the above code I've had no trouble with files larger
than the defined ASP buffer limit, but I haven't tried it with anything as
large as your file.
--
Dan
date: Thu, 3 Jul 2008 17:22:58 +0100
author: Daniel Crichton
Re: Adodb.Stream - Problem download big files
Daniel wrote to Anthony Jones on Thu, 3 Jul 2008 17:14:31 +0100:
> Anthony wrote on Thu, 3 Jul 2008 14:33:27 +0100:
>> "Juan" wrote in message
>> news:719A642C-56CF-49D0-9453-B75FC406E666@microsoft.com...
>>> Hi!
>>> I want to use ASP to download big files using ADODB.STREAM. It works
>>> very fine with files smaller than 80 MB.
>>> On the Webserver I can see that memory allocation and the process
>>> w3wp is running. After some time (more or less 2 minutes) I get a
>>> response
>> timeout.
>>> Set oStream = Server.CreateObject("ADODB.Stream")
>>> oStream.Type = adTypeBinary oStream.Open oStream.LoadFromFile(sfile)
>>> Response.AddHeader "Content-Length", oStream.Size ' -- Schönheit
>> Don't add the Content-Length header its a duplication, ASP adds that
>> for you.
> If the stream is being written out in chunks (which it is in the For
> Next loop), how does the ASP engine know what the final size will be?
Actually, I've just realised that the code I use myself doesn't set the
Content-Length header either. ASP doesn't add the Content-Length header
itself either as it has no idea what the file size is when it starts
outputting it, here's an example of the ASP headers from a download from my application:
HTTP/1.1 200 OK
Cache-Control: private
Date: Thu, 03 Jul 2008 16:26:53 GMT
Transfer-Encoding: chunked
Content-Type: application/pdf
Server: Microsoft-IIS/6.0
Content-Disposition: filename=Certifications_at_a_Glance.pdf;
This just means that you don't get the status bar in IE, for instance,
showing the download progress because the final size is not known. Adding
the Content-Length header allows IE (and any other browser that will show a
status bar) to give a progress with a final size value. I tested adding the
content length header to my own application and the headers changed to:
HTTP/1.1 200 OK
Cache-Control: private
Date: Thu, 03 Jul 2008 16:29:46 GMT
Transfer-Encoding: chunked
Content-Length: 1890660
Content-Type: application/pdf
Server: Microsoft-IIS/6.0
Content-Disposition: filename=Certifications_at_a_Glance.pdf;
and appeared to have no detrimental effect on the download.
--
Dan
date: Thu, 3 Jul 2008 17:31:59 +0100
author: Daniel Crichton
Re: Adodb.Stream - Problem download big files
"Daniel Crichton" wrote in message
news:eJHPSpS3IHA.1428@TK2MSFTNGP06.phx.gbl...
> Daniel wrote to Anthony Jones on Thu, 3 Jul 2008 17:14:31 +0100:
>
> > Anthony wrote on Thu, 3 Jul 2008 14:33:27 +0100:
>
> >> "Juan" wrote in message
> >> news:719A642C-56CF-49D0-9453-B75FC406E666@microsoft.com...
> >>> Hi!
>
>
> >>> I want to use ASP to download big files using ADODB.STREAM. It works
> >>> very fine with files smaller than 80 MB.
> >>> On the Webserver I can see that memory allocation and the process
> >>> w3wp is running. After some time (more or less 2 minutes) I get a
> >>> response
> >> timeout.
>
>
> >>> Set oStream = Server.CreateObject("ADODB.Stream")
> >>> oStream.Type = adTypeBinary oStream.Open oStream.LoadFromFile(sfile)
> >>> Response.AddHeader "Content-Length", oStream.Size ' -- Schönheit
>
> >> Don't add the Content-Length header its a duplication, ASP adds that
> >> for you.
>
> > If the stream is being written out in chunks (which it is in the For
> > Next loop), how does the ASP engine know what the final size will be?
>
> Actually, I've just realised that the code I use myself doesn't set the
> Content-Length header either. ASP doesn't add the Content-Length header
> itself either as it has no idea what the file size is when it starts
> outputting it, here's an example of the ASP headers from a download from
my application:
>
> HTTP/1.1 200 OK
> Cache-Control: private
> Date: Thu, 03 Jul 2008 16:26:53 GMT
> Transfer-Encoding: chunked
> Content-Type: application/pdf
> Server: Microsoft-IIS/6.0
> Content-Disposition: filename=Certifications_at_a_Glance.pdf;
>
>
> This just means that you don't get the status bar in IE, for instance,
> showing the download progress because the final size is not known. Adding
> the Content-Length header allows IE (and any other browser that will show
a
> status bar) to give a progress with a final size value. I tested adding
the
> content length header to my own application and the headers changed to:
>
> HTTP/1.1 200 OK
> Cache-Control: private
> Date: Thu, 03 Jul 2008 16:29:46 GMT
> Transfer-Encoding: chunked
> Content-Length: 1890660
> Content-Type: application/pdf
> Server: Microsoft-IIS/6.0
> Content-Disposition: filename=Certifications_at_a_Glance.pdf;
>
> and appeared to have no detrimental effect on the download.
>
You're right it doesn't have any detrimental affect on IE in fact it serves
a useful purpose. However it is a strictly a breach of the protocol See
http://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.4 para 3.
However the protocol does then indicate that if it is Content-Length is
present it should be ignored in this case.
--
Anthony Jones - MVP ASP/ASP.NET
date: Thu, 3 Jul 2008 22:17:13 +0100
author: Anthony Jones
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